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FACET FAQs

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Cameras: How often do cameras die from radiation?

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Title

How often do cameras die from radiation?

Question

​How often do cameras die from radiation?

Answer

The radiation environment at FACET has been characterized in a study here : see FAQ "How much dose is seen in the FACET tunnel"
 
Note that the study was with regards photon dose. The shielding does not affect neutron dose. The best method for the protection of equipment from neutrons is to put the camera outside of the accelerator housing and use mirrors. This has been done at SLAC but this is not typical at FACET.
 
Typically in FACET, available space precludes the use of shielding. Without shielding, our uncooled cameras (Manta GigEs)  typically last a year (~2000 hours of normal operations, located close to the beamline)  though there are particular "hot spots" where cameras will not last a week. These tend to be on the dump table and have been located both through dose measurement and trial and error. Cameras on the dump table are usually located where doses are found to be low and mirrors used as required. Cooled sensors (E-200 cameras: pco.Edge, Hamamatsu Orca) may have longer lifetimes but have also died from radiation at dump table hotspots on the ~week timescale. 
 
Due to the death-rate of cameras, we keep spares and design mounts such that cameras can be exchanged with minimal disruption.
 
Care must be taken during beamtime not to cause abnormal conditions that lead to camera damage particularly as cameras for multiple experiments tend to be installed at the same time. Abnormal beam loss can therefore affect other groups. It is important to be aware of the beam orbit. One case where the beam was not on the nominal orbit to the dump, a significant number of  cameras on the dump table died in a single shift.
 
 
 

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Version: 12.0
Created at 8/12/2019 1:56 PM by Clarke, Christine
Last modified at 8/14/2019 11:23 AM by Clarke, Christine

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