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FLS 2010 Program


Working Group 5: High Brightness Electron Guns :Public ViewUse SHIFT+ENTER to open the menu (new window).Open MenuOpen Menu

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Expand/Collapse Day : 1. Monday ‎(9)
Attachment3/1/2010 1:30 PM02:00 PM
Fernando Sannibale/ Fay HannonROB A/B
Attachment3/1/2010 2:00 PM02:30 PM
John LewellenROB A/B
Attachment3/1/2010 2:30 PM03:00 PM
Siggi SchreiberROB A/B
Attachment3/1/2010 3:00 PM03:30 PM
F. Sannibale/N. SerenoROB A/B
Nicholas Sereno

X-ray FEL Oscillator (XFEL-O) Gun Requirements and
R&D Overview

The XFEL-O promises large increases on average X-ray brightness
compared to 3rd generation and SASE sources.  In addition, it will
have the same peak brightness as SASE sources due to the very narrow
bandwidth of the output X-ray beam.  XFEL-O is an oscillator comprised
of a crystal cavity which selects photon energy based on the Bragg
condition.  In addition to full spatial coherence, XFEL-O has full
temporal coherence which will enable new capabilities complentary to
SASE and 3rd generation sources.  In this talk, we describe the
properties of the XFEL-O and show how these properties motivate a
rather unique combination gun emittance, repetiton rate and
micropulse charge.

Submitted by: Nicholas Sereno
Full Address:
Argonne National Laboratory
9700 South Cass Avenue Argonne IL 60439
E-Mail Address:
Attachment3/1/2010 3:30 PM04:00 PM
Eric EsareyROB A/B
Attachment3/1/2010 4:30 PM04:55 PM
Hirokazu MaesakaROB A/B
Attachment3/1/2010 4:55 PM05:20 PM
Dave DowellROB A/B
Attachment3/1/2010 5:20 PM05:45 PM
Siggi SchreiberROB A/B
Attachment3/1/2010 5:45 PM06:15 PM
Pietro Musumeci ROB A/B
Expand/Collapse Day : 2. Tuesday ‎(11)
Attachment3/2/2010 1:00 PM
Attachment3/2/2010 1:30 PM01:55 PM
Nobuyuki NishimoriROB A/B
Field emission from a structure inside an insulator such as a rod supporting cathode electrode is one of technical challenges to be addressed in photoemission DC guns. The field emission may lead to voltage breakdown or punch-through on ceramics. An insulator segmented with 10 ceramics and Kovar electrodes is employed to mitigate the field emission problem in JAEA/KEK photoemission gun. The segmented insulator provides uniform electric field on the ceramic surface and means to attach rings which literally guard ceramics against field emission. The guard rings and support rod are designed for the maximum field on the surface to be minimum.
High voltage processing was performed at base pressure of 3x10-8 [Pa]. Immediately after start of processing, -250kV was applied. After that, it takes a quarter hour for each 1kV step up to -500kV. The processing speed became slower from -500 kV to -550kV due to radiation increase. The integrated processing time was 110 hours up to -550kV. Stable operation at -500 kV for eight hours was also demonstrated. A radiation monitor and vacuum gauge showed no clear evidence for discharge or local heating due to dark current. A segmented insulator with guard rings is shown to be one of promising solutions to operate photoemission DC guns at -500 kV or more.
Attachment3/2/2010 1:55 PM02:20 PM
Fay HannonROB A/B
Attachment3/2/2010 2:20 PM02:45 PM
Charlie SinclairROB A/B
Attachment3/2/2010 2:45 PM03:10 PM
Tsukasa MiyajimaROB A/B
Attachment3/2/2010 3:10 PM03:35 PM
Ilan Ben-ZviROB A/B
Attachment3/2/2010 3:35 PM04:00 PM
Fernando SannibaleROB A/B
Attachment3/2/2010 4:30 PM04:55 PM
Ali NassiriROB A/B
Attachment3/2/2010 4:55 PM05:20 PM
John LewellenROB A/B
Attachment3/2/2010 5:20 PM05:45 PM
Jochen TeichertROB A/B
High Rep Rate Guns: FZD  Superconducting RF Photogun
J. Teichert1, A. Arnold1, H. Büttig1, D. Janssen1, M. Justus1, U. Lehnert1, P. Michel1,
K. Moeller1, P. Murcek1, Ch. Schneider1, R. Schurig1, G. Staats1, F. Staufenbiel1,
H. Tietze1, R. Xiang1, P. Kneisel2, B. v. d. Horst3, A. Matheisen3, J. Stephan4
 T. Kamps5, J. Rudolph5, M. Schenk5, G. Klemz6, I. Will6, V. Volkov7
1 FZ Dresden-Rossendorf, Dresden, Germany
2 JLab, Newport News, USA
3 DESY, Hamburg, Germany
4 IKS, Dresden, Germany
5 HZB, Berlin, Germany
6 MBI, Berlin, Germany
7 BINP, Novosibirsk, Russia

A RF photo injector with a superconducting cavity (SRF gun) for installation at the Radiation Source ELBE was developed within a collaboration of BESSY, DESY, FZD, and MBI. This new and promising injector type allows CW operation and has the potential for the production of high-brightness electron beams. The gun cryostat, the electron diagnostic beamline, and the driver laser with optical beamline were installed. In November 2007 the first beam was produced. In 2008 beam parameter measurements with Cs2Te photo cathodes were carried out. Due to problems during the cleaning of the cavity, the design gradient could not be reached. Thus the SRF gun is operating now with a peak field of 17.5 MV/m which corresponds to electron energy of 3 MeV. In 2009 the cathode transfer system was upgraded, the bunch lengths measurement based on Cherenkov radiation was put into operation, and the connection beamline to ELBE was installed in the winter shutdown. In February, the first beam of the SRF gun was injected to ELBE and accelerated. Parallel to the commissioning and operation of the SRF gun, an improved design for the gun cavity was created and two now cavities, one made of RRR300 Nb and one made of high-grain Nb was fabricated in collaboration with JLab.          
3/2/2010 5:45 PM06:15 PM
***All***ROB A/B
Expand/Collapse Day : 4. Thursday ‎(17)
Attachment3/4/2010 8:55 AM
Attachment3/4/2010 9:00 AM09:25 AM
Nick SerenoROB A/B
Attachment3/4/2010 9:25 AM09:50 AM
Feng ZhouROB A/B
Attachment3/4/2010 9:50 AM10:10 AM
Bruce CarlstenROB A/B
Attachment3/4/2010 10:30 AM11:10 AM
Dave DowellROB A/B
Attachment3/4/2010 11:10 AM11:35 AM
John SmedleyROB A/B
Diamond Amplifier – status and prospects
J. Smedley, I. Ben-Zvi, J. Bohon, X. Chang, E. Muller, J. Rameau, T. Rao, Q. Wu
Electron emission from diamond has been observed from hydrogen-terminated diamond.  The diamond electron amplifier has been demonstrated, with an emission gain of 40. The device relies on high-purity intrinsic diamond with low crystalline defect density, as well as a negative electron affinity achieved by hydrogen termination.  The effects of diamond purity and crystalline defects on charge transport in the material have been studied by IR spectroscopy, x-ray topography and x-ray response mapping, providing insight to where charge is trapped in the material, and how this trapped charge affects further charge transport. Very high average current densities (>10 A/cm2) have been transported through the diamond using x-ray generated carriers. Emission from the diamond surface has been studied by photoemission spectroscopy, total yield spectroscopy, and by measuring the emitted beam generated by incident energetic electrons.  The electron affinity of diamond has been measured to be -1.1 eV, along with the fraction of the electrons produced in the material which are emitted from the surface.
Attachment3/4/2010 11:35 AM12:00 PM
Kathy HarkayROB A/B
"Photocathode R&D at Argonne"

K. Harkay for Argonne Team

Argonne is interested in studying the fundamental physics of photocathode emission properties, correlating the intrinsic emittance of the emitted electrons with other properties of the surface, such as roughness, impurities/nonuniformity, laser polarization, etc. For ultrabright electron sources, we are interested in optimizing metal cathodes, given their robustness and fast response. An experimental chamber has been designed and assembly is underway to carry out angle-resolved photoemission spectroscopy to directly measure the emission momentum distribution while also measuring the surface chemistry. In parallel, theoretical investigations suggest a method of bandstructure engineering that can lower the work function and also the electron emittance.
After characterizing standard metal cathodes, promising novel cathodes will be fabricated and characterized experimentally to verify the theoretical predictions. Cathode R&D is also being pursued at Argonne for the large-area picosecond photodetector array project. Multialkali and III-V semiconductors are being studied in a multi-institutional collaboration. The goals for this project overlap with those for the ultrabright sources: e.g., fundamental R&D, long lifetime, cathode  design for optimal absorption and wavelength selection, fabrication. The status and plans for both areas -- ultrabright sources and detectors -- are presented.
Attachment3/4/2010 12:00 PM12:25PM
Triveni RaoROB A/B
Attachment3/4/2010 1:30 PM02:00 PM
Haward PadmoreROB A/B
Attachment3/4/2010 2:00 PM02:25 PM
Bill WhiteROB A/B
Attachment3/4/2010 2:25 PM02:50 PM
Carlo VicarioROB A/B
3/4/2010 2:50 PM03:15 PM
Shukui ZhangROB A/B
3/4/2010 3:15 PM04:00 PM
***All***ROB A/B
3/4/2010 4:00 PM06:00 PM
Attachment3/4/2010 4:30 PM04:50 PM
Florian LoehlROB A/B
Attachment3/4/2010 4:50 PM05:10 PM
Henrik LoosROB A/B
3/4/2010 5:10 PM06:00 PM
*** All ***ROB A/B
Expand/Collapse Day : 5. Friday ‎(1)
3/5/2010 11:30 AM12:00 PM
Panofsky Auditorium

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