Introduction/Setup Description
The EDC screen is an electron spectrometer screen designed to measure 'low-energy' scattered electrons that either do not reach the beam dump or require less background noise to be measured.
The EDC screen mount holds two screens in a W-shaped holder. The setup is mounted on a horizontal and vertical stage (both motorized UTS stages).
For the beam time Aug 10-15 2021, both screens were DRZ standard.
Aug: The screen is imaged via a mirror by a Mako G125-B with a small X mm lens (check with Erik) that sits outside of the EDC at a window port.
Since Oct/Nov 2021: The camera has been replaced by a Manta G895-B and a Navitar lens with 50 mm focal length and f 0.95, which optimises the field of view and collection efficiency.
Figure 1: Photos of installation during August downtime, looking from wall side (left) and showing the field of view in August on the Mako camera (right).
Figure 2: New field of view using Manta G895-B (this is slightly zoomed in) and light from beam losses in Nov 2021.
Motor positions
Current OUT position is 100 in vertical and 105 in horizontal
Current IN position is 50 in horizontal. To see the main beam 0 in vertical. To clear the beam just about by a few mm 10 in vertical.
http://physics-elog.slac.stanford.edu/facetelog/show.jsp?dir=/2021/32/11.08&pos=2021-08-11T23:13:18
These positions might change as the beam is being tweaked.
Note Nov 2021: OUT is 90 vertical and 75 horizontal. IN is 44 horizontal and visible up to 55 vertical.
Camera triggers
The camera triggers are the same as for the dump table in general.
Find them at Main screen → Event → Profile Monitor →SIOC:LI20:PM02 → Dump_Table
Note that all dump table diagnostics use the same trigger, so changing TDES will affect those as well.
Remote light for reference
A light can be activated remotely to visually check the position of the screen and confirm motors are moving (and to take reference images).
The light is just a lamp attached to the top view port of the chamber. It is plugged in to the PDC power strip.
It can be found under:
Main screen → Experimenter → LI20 → PDC Power Strip → EDC Chamber Lights
Relevant PVs
Shift summaries
Diagnostic checkout: http://physics-elog.slac.stanford.edu/facetelog/show.jsp?dir=/2021/32/12.08&pos=2021-08-12T10:04:37