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AD SLACPortal > Accelerator Research Division > FACET User Facility

Performance Metrics: User Time ("Pencil Beam")

 

Experiment: E-211 CERN BBA

Date: 3/11/2013

 

​Time beam delivered (hours): ​14.2 Time Promised (hours):​ ​12 ​
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​1.8 ​User off (hours): ​0 ​
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): ​16 ​ ​ ​ ​
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV​
​Delivered: 1.02e10 ​1.06e10 ​1.05e10 ​8.5e9 ​9.5e9
​Requested: ​1e10 1e10​ 1e10​ Not in request Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance  (mm mrad)

S2​ (x,y) S4 (x,y) S11​ (x,y) S18 (x,y)​ ​S20 (x,y)
Delivered: ​34, 2.7 ​25, 3.2 ​40, 6.4 ​42, 20
​Requested: Not in request Not in request ​Not in request ​Not in request Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​420 Bunch length requested (microns):​ ​ ​​Not in request ​
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available ​67 ​ ​ ​ ​

 

Summary from User:

Goals for the shift were achieved. Machine response matrix was identified and a reduction of eroneous dispersion by a factor 4 was obtained for the first half of the linac.

 

Experiment: E-211 CERN BBA

Date: 3/12/2013

 
 
​Time beam delivered (hours): ​8 Time Promised (hours):​ ​9 ​
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​0 ​User off (hours): ​0 ​
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): ​8 ​ ​ ​ ​
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 1.03e10 ​1.08e10 ​1.05e10 ​7.7e9 ​9.5e9
​Requested: ​1e10 ​1e10 ​1e10 ​Not in request ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: ​34, 2.7 ​27, 4.7 ​49, 5.5 ​63, 20
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​420 Bunch length requested (microns): ​​Not in request ​
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​50 ​ ​ ​ ​
 

Summary from User:

Goals for the shift were achieved. The global dispersion correction algorithm corrected the emittance after an intentional orbit distortion was introduced.
 
In the next shift we plan to verify that the algorithm can reduce the existing beam emittance in the second half of the linac.

 

Experiment: E-211 CERN BBA

Date: 3/16/2013

 
 
​Time beam delivered (hours): ​6 Time Promised (hours):​ ​8
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​0 ​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): ​6
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 9.3e9
​9.5e9 9.8e9
8.9e9
9e9
​Requested: ​1e10 ​1e10 ​1e10 ​Not in request ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 34, 3.1
26, 6.6
42, 12
45, 5.9
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​420 Bunch length requested (microns): ​​Not in request ​
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​0
 

Summary from User:

​Goals were partially achieved. We worked on the second half of the linac and corrected the dispersion that was present by a factor 3 in X and a factor 2 in Y. The accelerator operators could not make the measurement of the emittance in sector 18 so we have yet to prove the algorithm can reduce the emittance. We request a further shift to verify that the algorithm can reduce the existing beam emittance in the second half of the linac.

 

Experiment: E-211 CERN BBA

Date: 3/17/2013

 
 
​Time beam delivered (hours): ​8 Time Promised (hours):​ ​8
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​0 ​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): ​8
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 1.00e10
​1.04e10 1.02e9
9.4e9
9.3e9
​Requested: ​1e10 ​1e10 ​1e10 ​Not in request ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 34, 3.1
24, 6.2
39, 16
75, 16
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​420 Bunch length requested (microns): ​​Not in request ​
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​0
 

Summary from User:

​We identified and corrected the 2nd half of linac (LI11-LI18). We saw no improvement in the emittance that was present. Upstream oscillations could be flattened.

Results to be analyzed further in post processing.  We might request beam time with the low charge compressed optics pending analysis of our data.

 

Experiment: E-201 DIELECTRIC WAKEFIED ACCELERATION

Date: 3/20/2013

 

​Time beam delivered (hours): ​4 Time Promised (hours):​ ​4
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​User off (hours):
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): ​4
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV​
​Delivered: 9.9e9
1.02e10
​9.8e9 9.3e9
9.5e9​
​Requested: ​1e10 1e10
1e10
1e10
Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance  (mm mrad)

S2​ (x,y) S4 (x,y) S11​ (x,y) S18 (x,y)​ ​S20 (x,y)
Delivered: ​34, 3.0
​27,4.1
​39, 3.6
​62, 8.3
​147,10.6
​Requested: Not in request Not in request ​Not in request ​Not in request Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​420 Bunch length requested (microns):​ ​ ​​600
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available ​100

 

Summary from User:

The shift was dedicated to determine the golden orbit trajectory and align the laser to this orbit. The alignment laser provides a vector for precision alignment of the dielectric samples (~450um inner diameter). The laser alignment to beam orbit was achieved during this shift. 

We will align the dielectric samples using the results from this shift in the next access. In the next shift, we will measure the CTR spectra and the CCR spectra of the dielectric samples.


Experiment: E-202 ULTRAFAST MAGNETIC SWITCHING

Date: 3/20/2013

 
​Time beam delivered (hours): ​1 Time Promised (hours):​ ​2
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​User off (hours):
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 1
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 9.6e9 1.0e10 ​1e10 9.3e9​ 9.4e9
​Requested: ​1e10 1e10 1e10 1e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 28, 3.0​ ​27, 4.3 41, 3.5 63, 12.6 167, 9​
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​420 Bunch length requested (microns): ​​600
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​100
 

Summary from User:

  • The goal of the shift was to expose resistive film samples to long "pencil" beam
    to study the damage and possibly drive a metal to insulator transition in not so strong
    electric fields.
  • The goal was achieved. The same samples are scheduled to be exposed to compressed beam (10-20
    times shorter), where electric fields will be much higher.
 

Experiment: E-201 DIELECTRIC WAKEFIELD

Date: 3/22/2013

 
​Time beam delivered (hours): 4
Time Promised (hours):​ ​8
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​User off (hours):
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): ​4
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 9.6e9
​1e10 1e10
9.2e9
9.4e9
​Requested: 1e10​ ​1e10 ​1e10 1e10​
​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 38, 2.6
30, 5.8
45, 2.9
70, 5.6
Not measured​
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​420 Bunch length requested (microns): ​​600
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: 100​
 

Summary from User:

Not all goals were completed. The beam trajectory had changed since our last shift and the beam needed to be re-steered considerably. Once this was done, we successfully aligned our dielectric fibers to the beam. We expected to see coherent Cherenkov radiation from the beam interaction with the dielectric. However, we did not see meaningful signals on our detectors.
 
We have requested an access to FACET to exchange our detectors for more sensitive ones and we will repeat the measurement.

 

Experiment: E-201 DIELECTRIC WAKEFIELD ACCELERATION

Date: 3/23/2013

 
​Time beam delivered (hours): ​2.5 Time Promised (hours):​ ​8
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​User off (hours):
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): ​2.5
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 9.6e9
​9.9e9 9.8e9
9.1e9
9.4e9
​Requested: ​1e10 ​1e10 ​1e10 ​1e10
​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 39, 2.5
29, 1.8
47, 2.8
73, 7.5
​Not measured
​Requested: ​Not in request
Not in request
Not in request
Not in request
Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (microns): ​420 Bunch length requested (microns):  ​600
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​100
 

Summary from User:

 

This was a broadly successful shift. We accessed FACET to install a more sensitive detector. Signals were seen on the detectors that were correlated to the beam. Scanning the interferometer motor showed interference effects although a frequency spectrum has yet to be found in the data. We will analyse the data further.

We plan to take more data with the compressed bunch which is expected to result in much larger, clearer signals and interesting science as we enter a high field gradient regime.

 

Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 3/23/2013

 

​Time beam delivered (hours): ​12 Time Promised (hours):​ ​12
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​User off (hours): ​
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): ​12
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 9.6e9
​9.9e9 9.8e9
9.1e9
9.4e9
​Requested: ​1e10 ​1e10 ​1e10 ​1e10
​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 39, 2.5
29, 1.8
47, 2.8
73, 7.5
​Not measured
​Requested: ​Not in request
Not in request
Not in request
Not in request
Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (microns): ​420 Bunch length requested (microns):  ​600
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​30

Summary from User:

The goals for the shift were exceeded. The transverse deflecting cavity was brought online and the first bunch length measurement for FY13 was made. The notch collimator was used to divide the long bunch into two shorter bunches. This was imaged with the deflecting cavity clearly showing two separated bunches. This is a significant step towards delivering two bunches to the experimental area for plasma wakefield acceleration studies. The optics we require to collimate the more compressed bunch will be commissioned in April prior to delivery to the plasma wakefield acceleration experiment.





 

Performance Metrics: User Time ("Compressed Beam, Low Charge")

 

Experiment: E-202 ULTRAFAST MAGNETIC SWITCHING

Date: 4/2/2013

 
​Time beam delivered (hours): ​1 Time Promised (hours):​ ​2
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​0 ​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 1
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 9.5e9
1e10
8.7e9​ 7.5e9
9.5e9
​Requested: ​1e10 1e10 1e10 1e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 33, 3.4
​Not measured
37, 4.3
55, 11
​80, 23
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​30 Bunch length requested (microns): ​​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​100
 

Summary from User:

The goal of the shift was to expose resistive film samples to short compressed bunches to study the damage and possibly drive a metal to insulator transition in not so strong electric fields. The goal was achieved.

 

Experiment: E-201 DIELECTRIC WAKEFIELD

Date: 4/2/2013

 
​Time beam delivered (hours): 2
Time Promised (hours):​ ​2
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​User off (hours):
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): ​2
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 9.5e9
1e10​ 8.6e9
7.2e9
9e9
​Requested: 1e10​ ​1e10 ​1e10 1e10​
​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 31, 3.5
26, 2.8
38, 3.7
55, 12
75, 15​
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​38 Bunch length requested (microns): ​​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: 100​
 

Summary from User:

Marked location of beam centroid upstream and downstream of the Kraken chamber and aligned HeNe to these spots. Can now use HeNe to align dielectric structures to beam vector (N269) during the PAMM, use it to align the KOTR and align THz instrumentation. Exercised multi-screen IP TWISS cal routine with reasonable results but projected emittance is sensitive to residual dispersion.

 

Experiment: E-203 SMITH PURCELL LONGITUDINAL BUNCH MEASUREMENTS

Date: 4/2/2013

 

​Time beam delivered (hours): ​3.8 Time Promised (hours):​ ​4
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​User off (hours): ​
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): ​3.8
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 9.5e9
1e10
8.6e9
7.2e9
9.2e9
​Requested: ​1e10 ​1e10 ​1e10 ​1e10
​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 36, 3.1
Not measured
39, 4.5
58, 12
Not measured
​Requested: ​Not in request
Not in request
Not in request
Not in request
Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (microns): ​42 Bunch length requested (microns):  ​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​75

Summary from User:

The main objective of this run was to bring the gratings as close as possible to the beam (within 1 mm) to generate measurable signal (Smith Purcell Radiation) from the shortest period (50um) grating with amplitude at least 20 -30 ADC counts above the noise level ratio.

We struggled to bring the 50um grating close enough to observe such measurable signal (the measured signal was 10-20 counts above the noise level). We brought the grating to approximately 2mm range while simulations suggest we needed to be below 1 mm to see signal.

The longer period gratings gave stronger signals at 11 measured frequencies and via extrapolation and interpolation technique we performed a bunch profile reconstruction using Kramers-Kroning method .

We request additional beam time to address the issue of low signal with the 50um grating.

Experiment: E-201 DIELECTRIC WAKEFIELD

Date: 4/5/2013

 
​Time beam delivered (hours): 2
Time Promised (hours):​ 4
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​User off (hours):
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): ​2
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 9.2e9
9.7e9​ 7.5e9
7.3e9
7.3e9
​Requested: 1e10​ ​1e10 ​1e10 1e10​
​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 34, 3.3
28, 2.6
38, 4.5
55, 9.9
80, 23​
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​40 Bunch length requested (microns): ​​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: 100
 

Summary from User:

 

Beautifully produced a CTR interferogram of bunch length followed by CCR spectrum of cylindrical dielectric structure.This included a strong fundamental mode around 750 microns and smaller, but obvious 2nd order mode at 250 microns. Many thanks to the operators and everyone else who helped make this happen. 

Next shift we plan to send round beam through slab and repeat CCR scan.  Produce flat beam with (hopefully) 10:1 (sigma  x:y) ratio in transverse size to explore improved flat beam coupling in slab structures.


 

Experiment: E-201 DIELECTRIC WAKEFIELD

Date: 4/6/2013

 
​Time beam delivered (hours): 6.5
Time Promised (hours):​ 8
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​4.8 ​User off (hours): 0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): ​11.3
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 9.4e9
9.7e9
7.9e9
7.8e9
8.5e9
​Requested: 1e10​ ​1e10 ​1e10 1e10​
​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 33, 3.1
28, 2.8
37, 4.6
60, 12.4
80, 23​
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​30 Bunch length requested (microns): ​​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: 100
 

Summary from User:

Sending beam through slab structure and analyzing resultant CCR showed modes at ~800 micron and ~300 micron.  Also took data for 3:1 and 10:1 flat beams which may show improved coupling (i.e. more power) in those modes.  Increased beam CTR compared to tubes is indicator of reduced beam transport, which is believable considering reduced aperture to 240 from 450 microns.


Experiment: E-202 ULTRAFAST MAGNETIC SWITCHING

Date: 4/7/2013

 
​Time beam delivered (hours): ​1.1 Time Promised (hours):​ ​2
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​0 ​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 1.1
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 9.4e9
9.9e9
8.1e9
7.8e9
7.8e9
​Requested: ​1e10 1e10 1e10 1e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 27, 3.7
​28, 3.1
38, 5.1
55, 9.9
​61 (y not measured)
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​40 Bunch length requested (microns): ​​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​100
 

Summary from User:

The goal of the shift was to expose magnetic and resistive film samples to short compressed bunches to study switching (relevant to nonvolatile memory applications).The goal was achieved.

We request 2 hours of beamtime at full charge to expose thin iron film magnetic samples with compressed bunches. The useful magnetic pattern will be larger, while damage will be more localized in the center.


 

Experiment: E-203 SMITH PURCELL LONGITUDINAL BUNCH MEASUREMENTS

Date: 4/7/2013

 

​Time beam delivered (hours): ​7.0 Time Promised (hours):​ ​8
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​0.2 ​User off (hours): ​ ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): ​7.2
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 9.5e9
9.8e9
7.8e9
7.7e9
7.8e9
​Requested: ​1e10 ​1e10 ​1e10 ​1e10
​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 31, 2.9
25, 3.1
38, 6.2
58, 13
Not measured
​Requested: ​Not in request
Not in request
Not in request
Not in request
Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (microns): ​41 Bunch length requested (microns):  ​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​100

Summary from User:
We are happy to report that we achieved our the main goal of measuring a broad spectra ranging from 18um to 2200um. The main objective of this shift was to achieve reliable, measurable signals from all grating, including the 50um one, i.e. finding and bringing the gratings to the optimal distance to the beam thus avoiding detectors saturation and keeping Smith-Purcell signal above the noise level by least 20-30 counts. We managed to bring the 50um grating to close enough to the beam (in the range of 700um) and observed strong signal about ~100 counts above the noise level. During most of the shift the beam stability was exemplary except the last 1 hour when problems with klystrons were occurred.

If possible, we would like to ask for one more shift before the PAMM to see the effect of beam decompression, especially on the 50um grating signal.

 

Experiment: E-206 THz RADIATION MEASUREMENTS

Date: 4/8/2013

 

​Time beam delivered (hours): ​3.5 Time Promised (hours):​ ​2
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​0 ​User off (hours): ​ ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): ​3.5
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 9.1e9

8.5e9
7.3e9

​Requested: ​1e10 ​1e10 ​1e10 ​1e10
​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 28, 3.0
29, 4
38, 5
55, 12
Not measured
​Requested: ​Not in request
Not in request
Not in request
Not in request
Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (microns): ​34 Bunch length requested (microns):  ​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​100

Summary from User:
New beam optics is implemented for smaller transverse spot size on the USTHz foil (DSTHz profile: 140um x 140um before, 120um x 50um after). Pulse total energy, focal spot size, and power spectrum of THz radiation are measured with this new ebeam optics and the original ebeam optics for a direct comparison.


Experiment: E-203 SMITH PURCELL LONGITUDINAL BUNCH MEASUREMENTS

Date: 4/9/2013

 

​Time beam delivered (hours): ​4.5 Time Promised (hours):​ ​4
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​0 ​User off (hours): ​ ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): ​4.5
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 9.1e9
9.7e9
8.0e9
7.8e9
7.8e9
​Requested: ​1e10 ​1e10 ​1e10 ​1e10
​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 34, 3.2
31, 2.9
41, 6.0
57, 12
80, 23
​Requested: ​Not in request
Not in request
Not in request
Not in request
Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (microns): ​37, 87, 133 Bunch length requested (microns):  ​30 and longer
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​100

Summary from User:
The third run of E203 was successful. The goal of the run was to take measurements of electron bunch with different compressions:  1/ high compression sigma_z=36.9um (TCAV); 2/ intermediate compression sigma_z= 87um (TCAV) and 3/ low compression above 100um. The measurements (using 50um, 250um and 1500um gratings to cover wavelength region from 18um to 2200um) were done in conjunction with TCAV and THz measurements, allowing comparison of three different techniques. This is an important step to establish accurate understanding of pulse reconstruction using coherent Smith-Purcell radiation.  Pending the final analysis of our data, we are satisfied that the main goal of measuring bunches of different compressions in conjunction with TCAV and THz measurements was achieved. On the basis of these results, we would like to apply for beam time with the R56 10 mm configuration using collimation to produce more complex electron beam distribution (two bunches).


Performance Metrics: User Time ("Compressed Beam, High Charge")

 

Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 4/22/2013

 
​Time beam delivered (hours): ​7.5 Time Promised (hours):​ ​8
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​User off (hours):
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 7.5
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10
2.1e10
2.2e10
2.0e10
2.1e10
​Requested: ​2e10 2e10 2e10 2e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 12,3
32,5
44,6
71,9
​148,14
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured Bunch length requested (microns): ​​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​25
 

Summary from User:

This was a very successful first shift! With the high-charge compressed beam we observed the first beam-plasma interactions for this run with a Rb plasma. Preliminary findings are the following: We measured significantly stronger interaction than the last run (11 GeV in 28cm) with the ionization starting earlier in the bunch, as evidenced by the amount of charge participating in the wake, and a large amount of trapped charge (1E10 electrons/pulse) from the plasma. The higher beam intensity also produced significant ionization and wakefields in the Ar buffer gas in the bypass line. The symmetry of the betatron x-rays was correlated with incoming beam emittance (changed through spoiler foils) and incoming beam tilt introduced with the transverse deflecting cavity.



Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 4/23/2013

 
​Time beam delivered (hours): ​6 Time Promised (hours):​ ​8
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): ​User off (hours):
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 6
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10
2.0e10
2.1e10
1.9e10
2.0e10
​Requested: ​2e10 2e10 2e10 2e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 31,4
32,7
43,7.5
73,13
​Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured Bunch length requested (microns): ​​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​75
 

Summary from User:

The Rb plasma density was lowered to 7E16 e-/cc to better match the bunch length and recover acceleration of the tail particles. Preliminary analysis show energy up to 10GeV in 20cm plasma. The interaction/ionization if the Ar buffer gas was studied for different pressure. We realized that the ionization of the Ar (and potentially ionization of Rb++) could allow the dense beam emerging from the plasma to guide itself and propagate in a Ar plasma up to the exit of the buffer gas zone 1.75 meters downstream! In parallel we characterized and debugged several of the experimental diagnostics and data acquisition systems.


Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 4/27/2013

 
​Time beam delivered (hours): ​2.5 Time Promised (hours):​ ​11
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 0.25 ​User off (hours):
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 2.75
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 2.1e10 2.1e10 2.2e10 2.0e10 2.1e10
​Requested: ​2e10 2e10 2e10 2e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 36,2.5
29,2.6
64,12
Not measured
​Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured Bunch length requested (microns): ​​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​80
 

Summary from User:

We observed strong beam-plasma interaction in Argon at a pressure of 40 torr. Up to 14 GeV of deceleration was observed, corresponding to electrons exiting the plasma at 6 GeV of absolute energy. This is the highest deceleration observed at Facet so far. In addition, we realized the first direct observation of the plasma filament at FACET, at two different locations along the beam path by taking advantage of our OTR beam diagnostics. Interaction was found to be strongly enhanced by moving the waist toward the beginning of the Argon volume, which is compatible with an interaction occuring over a large propagation distance.


 

 

Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 4/28/2013 (Owl Shift)

 
​Time beam delivered (hours): ​8 Time Promised (hours):​ ​8
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours):
​User off (hours):
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 8
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10 2.1e10 2.2e10 2.0e10 2.1e10
​Requested: ​2e10 2e10 2e10 2e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 46,2.9
32,2.2
56,12
81,26
​Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured Bunch length requested (microns): ​​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​25
 

Summary from User:

Observed acceleration better than energy doubling through beam interaction with Argon plasma. Observed threshold for interaction at 2 Torr. Observed threshold for particle acceleration at 10 Torr. Scanned up to 32 Torr but observed best acceleration around 20 Torr, pressure for which the bunch length matches the plasma wavelength, with up to about 30 GeV energy gain. The use of a spoiler foil suppresses the interaction, which highlights that we are just above the threshold for Ar ionization.


Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 4/28/2013 (Swing Shift)

 
​Time beam delivered (hours): ​13.5 Time Promised (hours):​ ​12
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 0
​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 13.5
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10
2.1e10
2.1e10
2.0e10
2.1e10
​Requested: ​2e10 2e10 2e10 2e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 41,3.0
31,2.4
57,4.7
118,33
​Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured Bunch length requested (microns): ​​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​50
 

Summary from User:

Observed very good beam-plasma interaction in Rb gas, significantly better than last year.  Successfully characterized the Rb for several densities and bunch lengths.  Clear observation of hosing for a number of the working points; observed dependence on hosing on sextupole knob.


Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 4/29/2013

 
​Time beam delivered (hours): ​4.7 Time Promised (hours):​ ​6
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 0
​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 4.7
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10
2.0e10
2.1e10
1.9e10
2.0e10
​Requested: ​2e10 2e10 2e10 2e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 31,2.6
31,1.6
41,3.5
63,14
​Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured Bunch length requested (microns): ​​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​100
 

Summary from User:

Observed steady acceleration of +10 GeV in Rb.  Studied effect of transverse knobs to induce or suppress instabilities in the accelerated particles - saw clear effects.  Characterized the interaction at 4 different waist beta configs, two asymmetric and two symmetric. 


Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 5/10/2013

 
​Time beam delivered (hours): ​9.4 Time Promised (hours):​ ​12
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 0
​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 9.4
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 2.1e10
2.1e10
2.3e10
2e10
2.2e10
​Requested: ​2e10 2e10 2e10 2e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 43,3.1
42,1.6
74,5.3
149,11
​Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured Bunch length requested (microns): ​​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available:
 

Summary from User:

The beam was able to ionize He, which has a very high ionization energy of 25 eV. Good beam-plasma interaction with He was observed during this shift. Observed threshold for interaction at ~16 Torr, and at 32 Torr, electrons were observed to be decelerated from 20 GeV to below 2 GeV, i.e. more than 18 GeV of energy loss. No acceleration was observed in He.

 


Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 5/11/2013

 
​Time beam delivered (hours): ​12 Time Promised (hours):​ ​12
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 0
​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 12
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 2.1e10
2.1e10
2.3e10
2.0e10
2.2e10
​Requested: ​2e10 2e10 2e10 2e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 42,2.5
34,1.4
46,5.3
88,8.1
​62,35
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured Bunch length requested (microns): ​​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​83
 

Summary from User:

Beam was able to ionize He but with no acceleration. Significant deceleration with possible trapped charge acceleration observed in Li. We studied the effects of longitudinal beam tuning on the acceleration signal and saw no improvement.

Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 5/12/2013

 
​Time beam delivered (hours): ​11.5 Time Promised (hours):​ ​12
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 0
​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 11.5
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10
2.0e10
2.1e10
1.8e10
2.1e10
​Requested: ​2e10 2e10 2e10 2e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 32,2.6
34,1.2
48,8.1
Not measured
76,16
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured Bunch length requested (microns): ​​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available:
 

Summary from User:

The beam-plasma interaction with the Li oven with 10% of Ar impurity in the He buffer gas was studied. Trapping was present as evidenced by the toroid downstream of the plasma, and possible candidates for trapped electrons were identified on the Cherenkov spectrometer during the first part of the shift. Interaction was degraded when going to lower beta functions during the second part of the shift. Almost no acceleration was observed during the shift, despite the optimization of the bunch profile and the use of higher plasma densities.


Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 5/13/2013

 
​Time beam delivered (hours): ​11 Time Promised (hours):​ ​12
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours):
​User off (hours):
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 11
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10
2.1e10
2.2e10
1.9e10
2.1e10
​Requested: ​2e10 2e10 2e10 2e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: Not measured
44,1.2
54,6.3
95,11
Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured Bunch length requested (microns): ​​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available:
 

Summary from User:

The beam-plasma interaction with the Li oven with Ar impurity in the He buffer gas was studied, with concentration of 10%, 21% and 50%. A parameter scan was performed with the goal of improving the wake amplitude. The amplitude was diagnosed with the amount of energy loss. Even though the amount of the energy loss, and thus the wake, was improved during the shift, the accelerated electrons, which we expected to come from Ar ionization inside the wakefield, were not directly observed on the Cherenkov diagnostic. Low quality trapped charge was however observed on the scintillator screen intended to gamma-ray measurements.

Up to 20 GeV of acceleration was observed in the Li plasma when disabling the He/Ar ionization by increasing the beam transverse emittance. Up to 10 GeV of acceleration was observed in the He/Ar plasma for an impurity level of 50%. When combining both the He/Ar plasma stage and the Li plasma stage, the acceleration was observed to be suppressed, which is experimental evidence for the dephasing between the two plasma stages.

Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 5/14/2013

 
​Time beam delivered (hours): ​7.3 Time Promised (hours):​ ​12
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours):
​User off (hours): ​1.0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 8.3
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 2.1e10
2.1e10
2.2e10
2.0e10
2.1e10
​Requested: ​2e10 2e10 2e10 2e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 34,3.0
34,2.1
35,9.1
80,8.5
Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured Bunch length requested (microns): ​​30
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​88
 

Summary from User:

Good evidence for ionization injection into a Plasma Wakefield Accelerator (PWFA). One or more electron features, distinguished by their narrow angular spread and relative brightness, appear at the image plane of the electron spectrometer along with the usual wake-field perturbed SLAC electron beam (energy gain and loss--the normal PWFA result). Evaluating the energy of the narrow features will require post-processing of the data.

We expect short bursts of charge to be trapped in the the wakefield if a minority impurity species intermixes with the Lithium vapor column within the boundary layer. In the first one or two foci of the SLAC beam--in the up-ramp of the Lithium vapor column--the minority impurity species can be field ionized by the collapsing (focusing) SLAC beam, releasing new electrons in such a phase that they are inside the main wakefield. They can begin at rest and leave the plasma with 10's of GeV. It is thought that the narrow features mentioned above are these ionization-injected electrons.


Experiment: E-201 DIELECTRIC WAKEFIELD

Date: 5/18/2013

 
​Time beam delivered (hours): ​10.2 Time Promised (hours):​
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 2.6
​User off (hours): ​5.2
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 18
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 2.1e10
2.1e10
2.3e10
2.0e10
0
​Requested: ​2e10 2e10 2e10 2e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 34,2.8
37,3.7
63,14
94,13
Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured Bunch length requested (microns): ​​100
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​97
 

Summary from User:

The procedure for aligning the laser to the beam and the tube to the has been nailed down.  We weren't lucky.  We used the time while the beam was down to iron out issues in the on the fly analysis tools and get motor coordinates for future tubes.  Unfortunately, even while the beam was nominally up, the bunch length pyro was unstable indicating the beam wasn't very useful.


Experiment: E-201 DIELECTRIC WAKEFIELD

Date: 5/19/2013

 
​Time beam delivered (hours): 13.7 Time Promised (hours):​
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 1.1
​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 14.8
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10
2.1e10
2.1e10
2.0e10
0
​Requested: ​2e10 2e10 2e10 2e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 36,2.3
35,2.4
58,6.1
86,18
Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured Bunch length requested (microns): ​​100
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​97
 

Summary from User:

Sent beam through 1 cm tubes, signal was thought to be too low to resolve proper peak.  Increased signal by switching to 10 cm tube, which uses a better designed coupling horn as well as more energy due to length.  Saw desired signal, improvements can be made with more points, wider scan range and background subtraction.


Experiment: E-201 DIELECTRIC WAKEFIELD

Date: 5/20/2013

 
​Time beam delivered (hours): ​8.1 Time Promised (hours):​
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours):
​User off (hours):
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 8.1
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10
2.0e10
2.1e10
1.8e10
0
​Requested: ​2e10 2e10 2e10 2e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 37,2.4
33,1.9
56,7.5
89,16
Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured Bunch length requested (microns): ​​100
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​15
 

Summary from User:

Measured ~540MeV/m gradients in a 10cm long, 450um inner diameter dielectric tube with a 25um copper coating. The 54MeV energy change is a world record for dielectric wakefield accelerators. The spectrum of the wakefields excited in the structure agreed with the design predictions.

 

Experiment: E-201 DIELECTRIC WAKEFIELD

Date: 5/21/2013

 
​Time beam delivered (hours): 6.1 Time Promised (hours):​ ​7
​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 0 ​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 6.1
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10 2.1e10 2.2e10 1.9e10 0
​Requested: ​2e10 2e10 2e10 2e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 32,2.3 25,1.4 53,3.2 79,8.1 Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured Bunch length requested (microns): 40
 ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​97
 

Summary from User:

We sent beam through a 10cm long 450 micron inner diameter tube made of silica and measured ~80MeV energy change (800 MV/m gradients) which is a new world record. The spectrum from the wakefields in the tube agreed with our prediction.  We must further investigate correlations with energy feedback to clear up some other odd results.  If numbers hold it means we are extracting 240 mJ of energy from the beam.


Experiment: E-202 ULTRAFAST MAGNETIC SWITCHING

Date: 5/24/2013

 
​Time beam delivered (hours): 2 Time Promised (hours):​ ​2
​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 0 ​User off (hours): ​ ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 2
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10 2.0e10 2.2e10 1.8e10 0
​Requested: ​2e10 10 2e10 2e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 30,2.1 30,2.2 54,7.7 64,10 Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured Bunch length requested (microns): 40
 ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​100​
 

Summary from User:

Samples were exposed with full charge enabling larger fields for switching of domains in ferroelectric samples. Different resistive structures were used to evaluate the damage due to an enhanced electric field.


 

Laser and E-200 Experiment Commissioning reports


Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/7/2013

Laser Energy Delivered (mJ): ​1 Laser Energy Requested (mJ): ​1
Laser Pulse Duration Delivered (fs):
​200
Laser Pulse Duration Requested (fs): ​200
 

Summary from User:

We were exceptionally pleased with our first delivered laser pulses of the requested pulse duration and good spatial chirp. After the Ti:Sapph laser was set-up to our request, we spent time gaining competency with our installation to send the Ti:Sapph laser beam into the E200 PWFA experimental apparatus. During our dry-run for the installation of these optical components, we identified the need to make a small modification to the stage assembly for the turning mirror. In our next access, we plan to have the modification made and the full optical installation in place.

Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/10/2013

Laser Energy Delivered (mJ): ​- Laser Energy Requested (mJ): ​-
Laser Pulse Duration Delivered (fs):
​-
Laser Pulse Duration Requested (fs): ​-
 

Summary from User:

The goals for this shift were to install the modified stage assembly and turning mirror and to install the axicon lens and view its profile with a low power alignment laser. The goals were not achieved due to wires breaking. Work finally stopped when a member of the team broke a vacuum window.

Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/12/2013

Laser Energy Delivered (mJ): ​- Laser Energy Requested (mJ): ​-
Laser Pulse Duration Delivered (fs):
​-
Laser Pulse Duration Requested (fs): ​-
 

Summary from User:

We successfully installed the stage assembly and turning mirror and also the axicon lens. We viewed the profile of the low power alignment laser after the axicon. The next step is to verify the electron beam trajectory and make any necessary adjustments to the laser alignment prior to starting Ti:Sapph studies.


 

Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/15/2013

Time beam delivered (hours): 0.2 Time beam requested (hours):
0.2​
 

Summary from User:

Using the R56 10 mm setting, we viewed the electron beam pass through the hole of our turning mirror that injects the laser onto the electron beam path. The alignment of the optics for integrating the laser with the experiment was highly successful and only minor tweaks were identified for the next access. 


Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/16/2013

Laser Energy Delivered (mJ): ​1 Laser Energy Requested (mJ): ​1
Laser Pulse Duration Delivered (fs):
​Not measured
Laser Pulse Duration Requested (fs): ​Not requested
 

Summary from User:

We made minor adjustments based on the observed electron beam trajectorty and aligned the axicon lens with the low power alignment laser. We switched to using the Ti:Sapph laser. Steering the laser through the transport system (approximately 30 meters) took more time than planned for and we did not complete measurements of the profile of the laser after the axicon lens. However, the set-up is ready for the Ti:Sapph laser. We request an increase in laser energy prior to our next shift.


Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/18/2013

Laser Energy Delivered (mJ): ​5 Laser Energy Requested (mJ): ​5
Laser Pulse Duration Delivered (fs):
​300
Laser Pulse Duration Requested (fs): ​300
 

Summary from User:

The 800nm Ti:Sapph laser was successfully brought into the plasma wakefield acceleration apparatus for the first time. Various studies were completed including pointing jitter (which was of an acceptable level) and beam profiles at various positions after the axicon lens. The beam profiles were not ideal and it is suspected that the main source of the issue was in the laser room. We request that the beam profile and spatial chirp is improved. We also identified some aperture clipping which we will investigate and resolve next.


Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/20/2013

Laser Energy Delivered (mJ): ​1 Laser Energy Requested (mJ): ​1
Laser Pulse Duration Delivered (fs):
​300
Laser Pulse Duration Requested (fs): ​300
 

Summary from User:

The observed clipping was investigated and resolved. Beam profiles had not improved though damaged mirrors had been replaced. The source of the non-ideal beam profiles still needs to be identified though we can proceed with the experiment even in this state. There are no issues that prevent us from sending high power laser to the experiment to attempt ionization.  Our next step is to adjust the timing of the laser to the electron beam.

 

Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/21/2013

Laser Energy Delivered (mJ): ​380 Laser Energy Requested (mJ): ​500
Laser Pulse Duration Delivered (fs):
​300
Laser Pulse Duration Requested (fs): ​300
 
Time beam delivered (hours): 8
Time beam requested (hours):
2
 

Summary from User:

The laser triggering was reconfigured to be timed to the FACET electron beam. The timing was verified with beam. We found the timing jitter to be within the resolution of our measurement (1ns) and we tested our ability to make fine adjustment of the timing. Coarse adjustment of the timing will be tested tomorrow.

 

Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/22/2013

Laser Energy Delivered (mJ): ​250 Laser Energy Requested (mJ): ​500
Laser Pulse Duration Delivered (fs):
​300
Laser Pulse Duration Requested (fs): ​300
 
Time beam delivered (hours): 0.5
Time beam requested (hours):
0.5
 

Summary from User:

The coarse adjustment of the timing was tested and was successful. An access to FACET was used to verify the alignment and ready the apparatus for argon and lithium plasma studies. The low delivered energy is a concern for the goal of generating a plasma filament.

 

Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/23/2013

Laser Energy Delivered (mJ): ​350 Laser Energy Requested (mJ): ​500
Laser Pulse Duration Delivered (fs):
​300
Laser Pulse Duration Requested (fs): ​300
 
 
​Time beam delivered (hours): 11
Time Promised (hours):​ ​9
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 0
​User off (hours): ​1
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 12
​ ​ ​ ​ ​ ​

Charge​ (electrons/bunch)

S2​ S10​ S19 S20​ SCAV
​Delivered: 2.1e10
2.1e10
2.2e10
2.0e10
2.1e10
​Requested: ​2e10 2e10 2e10 2e10​ ​Not in request
​ ​ ​ ​ ​ ​

​Normalized emittance (mm mrad)

S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 33,2.2
30,3.4
46,4.6
66,13
Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured.
Bunch length requested (microns): ​​Not in request.
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​100
 

Summary from User:

The goal in this shift was to observe a plasma filament in the argon caused by the laser. This was not seen, possibly due to multiple contributing factors including a misalignment of the laser to the axicon lens. Remote alignment failed and the cause will need to be investigated in an access to FACET. We completed the energy spectrometer calibration and vignetting scan and characterized the new orbit planned for E200 experiments.


Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/24/2013

Laser Energy Delivered (mJ): ​0.4 Laser Energy Requested (mJ): ​5
Laser Pulse Duration Delivered (fs):
​300
Laser Pulse Duration Requested (fs): ​300
 

Summary from User:

We accessed FACET and measured the laser beam intensity after the compressor and found it to be significantly lower than expected. We recovered the high intensity laser beam by changing the polarization in the laser room. This is certainly the largest contributing factor to the lack of argon ionization yesterday. We recovered our motors for remote alignment of the axicon lens. Our transverse laser beam profiles were re-measuremed and are still not optimal.


Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/25/2013

Laser Energy Delivered (mJ): ​400 Laser Energy Requested (mJ): ​500
Laser Pulse Duration Delivered (fs):
​300
Laser Pulse Duration Requested (fs): ​300
  

 

Summary from User:

We successfully created a plasma filament in argon gas. This is a significant milestone that indicates that the laser is now ready to ionize lithium (first electron ionization energy of argon is three times that of lithium). The E200 lithium oven will be prepared for the experiment with laser-ionized lithium plasma and electron beam for first signs of wakefield acceleration. We can also confirm that the laser beam profiles look good after work by the laser group this morning.

 

Performance Metrics: User Time ("Two Bunch Configuration")

Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/26/2013

Laser Energy Delivered (mJ): ​400 Laser Energy Requested (mJ): ​500
Laser Pulse Duration Delivered (fs):
​300
Laser Pulse Duration Requested (fs): ​300




​Time beam delivered (hours): 3
Time Promised (hours):​ ​ongoing
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 0
​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 3
​ ​ ​ ​ ​ ​
Charge​ (electrons/bunch)
S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10
2.1e10
2.2e10
1e10 drive, 0.7e10 witness
2.1e10
​Requested: ​2e10 2e10 2e10 2:1 charge ratio, drive:witness
​Not in request
​ ​ ​ ​ ​ ​
​Normalized emittance (mm mrad)
S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 38,2.6
29,5.1
42,5.1
71,9.2
Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): 40um drive, 38 um witness. 160um separation.
Bunch length requested (microns): ​​35um drive, 20 um witness. 150um separation.
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​0
 
Summary from User:
The goals for the shift were to ionize lithium and witness plasma-electron bunch interaction using the energy spectrometer diagnostics. Hardware issues made progress in setting up both the electron beam and the laser beam slow. Issues will be looked at and the goals will be achieved on the next shift instead.


Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/28/2013

Laser Energy Delivered (mJ): ​350 Laser Energy Requested (mJ): ​500
Laser Pulse Duration Delivered (fs):
​300
Laser Pulse Duration Requested (fs): ​300

​Time beam delivered (hours): 4
Time Promised (hours):​ ​ongoing
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 0
​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 4
​ ​ ​ ​ ​ ​
Charge​ (electrons/bunch)
S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10
2.0e10
2.1e10
1.7e10
2.1e10
​Requested: ​2e10 2e10 2e10 2:1 charge ratio, drive:witness
​Not in request
​ ​ ​ ​ ​ ​
​Normalized emittance (mm mrad)
S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 34,2.2
28,4.5
52,7.2
69,14
Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Single bunch 90um. Two bunches not measured.
Bunch length requested (microns): ​​Single bunch unspecified. Two bunch request: 35um drive, 20 um witness. 150um separation.
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​100
 
Summary from User:
We used the laser to pre-ionize the lithium plasma approximately 100 ps in advance of a single electron bunch. There was noticeably more charge participating in the electron-plasma interaction with the laser than without. We went to the two-bunch configuration with pre-ionization and observed deceleration of electrons due to the plasma wake. Optimisation of laser, e-beam and plasma will need to take place on the next shift to achieve acceleration. 

Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/29/2013 - OWL SHIFT

Laser Energy Delivered (mJ): ​375 Laser Energy Requested (mJ): ​500
Laser Pulse Duration Delivered (fs):
​300
Laser Pulse Duration Requested (fs): ​300

​Time beam delivered (hours): 6
Time Promised (hours):​ ​ongoing
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 0
​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 6
​ ​ ​ ​ ​ ​
Charge​ (electrons/bunch)
S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10
2.1e10
2.2e10
1.9e10
2.1e10
​Requested: ​2e10 2e10 2e10 2e10
​Not in request
​ ​ ​ ​ ​ ​
​Normalized emittance (mm mrad)
S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 34,2.3
28,4.5
57,4.8
72,8.3
Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​80
Bunch length requested (microns): ​​Single bunch (unspecified)
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​83
 
Summary from User:
We tuned the laser beam and aligned it carefully to electron beam on the two OTR foils available, using a new, faster procedure (e-beam and laser simultainously on foils).  We observed a much improved interaction interaction of an overcompressed ebeam with laser on with respect to laser off. Satisfied that everything was set up in an optimal way, we asked to be set up for two bunches.

Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/29/2013 - DAY SHIFT

Laser Energy Delivered (mJ): ​355 Laser Energy Requested (mJ): ​500
Laser Pulse Duration Delivered (fs):
​300
Laser Pulse Duration Requested (fs): ​300

​Time beam delivered (hours): 4
Time Promised (hours):​ ​ongoing
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 1.8
​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 5.8
​ ​ ​ ​ ​ ​
Charge​ (electrons/bunch)
S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10
2.1e10
2.2e10
7e9 drive, 6e9 witness
2.1e10
​Requested: ​2e10 2e10 2e10 2:1 charge ratio, drive:witness
​Not in request
​ ​ ​ ​ ​ ​
​Normalized emittance (mm mrad)
S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: Not measured
Not measured
Not measured
Not measured
Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​23um drive, 54 um witness. 145um separation
Bunch length requested (microns): ​​35um drive, 20 um witness. 150um separation.
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​100
 
Summary from User:
This was a hugely significant shift wherer we observed clear signs of two-bunch plasma wakefield acceleration with the laser-ionised lithium plasma. With the laser on, the drive bunch lost energy and the witness bunch gained energy whereas little interaction was seen with the laser off. Studies remain to optimize the collimation of the two bunches and the position of the waist of the e-beam with respect to the plasma ramp. During the swing shift, we will pump out the argon in the experimental chamber and replace it with helium for a sharper plasma ramp profile.

Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/30/2013 - OWL SHIFT

Laser Energy Delivered (mJ): ​355 Laser Energy Requested (mJ): ​500
Laser Pulse Duration Delivered (fs):
​300
Laser Pulse Duration Requested (fs): ​300

​Time beam delivered (hours): 5
Time Promised (hours):​ ​ongoing
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 0
​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 5
​ ​ ​ ​ ​ ​
Charge​ (electrons/bunch)
S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10
2.0e10
2.1e10
8e9 drive, 7e9 witness
2.0e10
​Requested: ​2e10 2e10 2e10 2:1 charge ratio, drive:witness
​Not in request
​ ​ ​ ​ ​ ​
​Normalized emittance (mm mrad)
S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 36,2.1
31,4.0
49,5.7
69,13
Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​31um drive, 71um witness. 175um separation.
Bunch length requested (microns): ​​35um drive, 20 um witness. 150um separation.
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​60
 
Summary from User:
In this shift we optimized the position of the e-beam waist with respect to the plasma ramp in our lithium oven (with helium buffer gas) by watching the e-beam-plasma interaction. However, we did not see a significant difference between laser on/laser off. We would like the e-beam to be checked and retuned if necessary before our next shift.

Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/30/2013 - DAY SHIFT

Laser Energy Delivered (mJ): ​370 Laser Energy Requested (mJ): ​500
Laser Pulse Duration Delivered (fs):
​300
Laser Pulse Duration Requested (fs): ​300

​Time beam delivered (hours): 2.7
Time Promised (hours):​ ​ongoing
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 0.1
​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 2.8
​ ​ ​ ​ ​ ​
Charge​ (electrons/bunch)
S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10
2.1e10
2.2e10
1.4e10 combined
2.1e10
​Requested: ​2e10 2e10 2e10 2:1 charge ratio, drive:witness
​Not in request
​ ​ ​ ​ ​ ​
​Normalized emittance (mm mrad)
S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: 36,2.3
Not measured
53,4.7
92,11
Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​Not measured
Bunch length requested (microns): ​​35um drive, 20 um witness. 150um separation.
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​100
 
Summary from User:
Fine adjustment of the laser timing on the 100ps level restored the good e-beam -plasma interaction with the laser on. We request that the longitudinal set up is recharacterized for our final shift.


Experiment: E-200 PLASMA WAKEFIELD ACCELERATION

Date: 6/30/2013 - SWING SHIFT

Laser Energy Delivered (mJ): ​380 Laser Energy Requested (mJ): ​500
Laser Pulse Duration Delivered (fs):
​300
Laser Pulse Duration Requested (fs): ​300

​Time beam delivered (hours): 5
Time Promised (hours):​ ​ongoing
​ ​ ​ ​ ​ ​
​Unscheduled accelerator downtime (hours): 0
​User off (hours): ​0
​ ​ ​ ​ ​ ​
​Total Time (delivered+downtime+user off, hours): 5
​ ​ ​ ​ ​ ​
Charge​ (electrons/bunch)
S2​ S10​ S19 S20​ SCAV
​Delivered: 2.0e10
2.1e10
2.2e10
5e9 drive, 4e9 witness
2.1e10
​Requested: ​2e10 2e10 2e10 2:1 charge ratio, drive:witness
​Not in request
​ ​ ​ ​ ​ ​
​Normalized emittance (mm mrad)
S2​ (x,y) S4 (x,y) S11 (x,y)​ S18​ (x,y) ​S20 (x,y)
Delivered: Not measured
Not measured
53,8.7
68,8.5
Not measured
​Requested: ​Not in request ​Not in request ​Not in request ​Not in request ​Not in request
​ ​ ​ ​ ​ ​
​Bunch length delivered (rms, microns): ​28um drive, 57um witness. 170um separation
Bunch length requested (microns): ​​35um drive, 20 um witness. 150um separation.
​ ​ ​ ​ ​ ​
​% time accelerator support physicist available: ​100
 
Summary from User:



SLAC SLAC National Accelerator Laboratory, Menlo Park, CA
Operated by Stanford University for the U.S. Dept. of Energy