Detectors at MEC
By "detector" we typically mean "imaging cameras read out in the LCLS DAQ". MEC uses the same cameras found at other LCLS hutches, such as ePix, Jungfrau, (add more here). These are cameras built by and for the scientific community. In addition MEC supports several commercial cameras, including (add list here). All of these cameras have 100k+ sub-mm pixels and are sensitive to X-rays. Most can be used in either vacuum or air.
MEC-specific detector issues
Detector use at MEC is different than at other LCLS beamlines in several ways.
- Detectors at MEC need to be EMP tolerant for some experiments. We used to see pedestal shifts, voltage upsets, and even detector damage but have improved grounding and shielding. We currently do not seem to have problems with the current suite of detectors.
Alan Conder wrote a technical note about best practices for a detector to survive an EMP environment, describing grounding and cabling. - Please be aware of the possibility of sample-related shrapnel.
- MEC is unusual in taking isolated shots. Many cameras run at different temperature depending on the trigger rate, especially in vacuum. Whenever possible we prefer to run cameras in a steady state. Epix cameras receive a "run" trigger at 120 Hz but are read out at any user specified rate. For so-called "slow" cameras like the UXI we advise users to take some number (O(5)) of dark frames immediately before taking science frames.