CXI has two in-vacuum 2.3M CSPAD pixel-array detectors. Each detector is stationed downstream of one of CXI's three interaction points and can be read-out individually, together, or independently – allowing CXI the capability to operate two experiments simultaneously using a single X-Ray beam. When running two experiments during the same shift, the upstream experiment uses the DS1 CSPAD in the primary DAQ from cxi-daq, while the downstream parasitic experiment will use the DS2 CSPAD in the secondary DAQ from cxi-monitor.
The names DS1 and DS2 refer to the vacuum chambers that contain the CSPAD detectors. The chambers also contain a handful of motorized beamline components such as pulse pickers, beamstops, vacuum gauges, and alignment stages. Taking a look at the EPICS PV descriptions of the detector chamber motors, we can get an idea of what else is inside them.
Obtaining the descriptions of the DS1 motors using caget,
cxi-control:~> echo -e "Motor PV\t\t\tDescription:"; caget CXI:DS1:MMS:{01..14}.DESC
Motor PV Description:
CXI:DS1:MMS:01.DESC vee_slide (m5) X US North
CXI:DS1:MMS:02.DESC vee_lift (m4) Y US North
CXI:DS1:MMS:03.DESC flat_lift (m3) Y US South
CXI:DS1:MMS:04.DESC cone_slide (m2) X DS
CXI:DS1:MMS:05.DESC cone_lift (m1) Y DS
CXI:DS1:MMS:06.DESC In-Vacuum LS-180
CXI:DS1:MMS:07.DESC Be lenses X
CXI:DS1:MMS:08.DESC Be Lenses Y (not locked out)
CXI:DS1:MMS:09.DESC ATT X
CXI:DS1:MMS:10.DESC ATT Y
CXI:DS1:MMS:11.DESC ATT Z
CXI:DS1:MMS:12.DESC PP X Stepper Motor
CXI:DS1:MMS:13.DESC PP Y Stepper Motor
CXI:DS1:MMS:14.DESC Pulse Picker Motor
and DS2,
we find the motors are for alignment stages, X-Ray focusing optics, a pulse picker, attenuator and more.
EDM control GUIs for detector chamber devices can be pulled up using the CXI Home Screen and clicking the "DSA", "DSC", "DSD" icons for detector power, and "DS1", "DS2" motor status circles as they appear under detector stand locations on the beamline map (top left of images). Note that the motor control screens for the detector chamber motors are password protected and beamline staff have sworn a sacred oath to never speak the password to anyone ever. If an HXR staff member reveals the password to you, please report them to Sebastien Boutet so he may take punitive action.
DS1 and DS2 have companion mobile equipment racks, named D50 and D51 respectively. The racks are nearly identical twins and each contain power supplies and readout electronics for detectors, a Digi, a 4-channel stepper motor controller and an EPICS IOC server. The mobile racks handle controls and feedback for detector power and diagnostics, some stepper motor control, and serve as an interface for detector data and timing input/output. A rack profile listing of the mobile racks' devices is shown below.
| Mobile Detector Rack Profile | |
|---|---|
| CSPAD Concentrator | Handles CSPAD data readout |
| Detector PDU | Consolidates power from MPOD with other analog control and timing signals to detector input |
| MPOD | EPICS controllable High/Low voltage power supply for detectors |
| EPICS IOC Server | IOC for motors, encoders and power supplies running from the mobile rack |
| Digi Serial Port Server | Serial communication input/output terminal |
| Dumb Motor Controller | For in-vacuum LS-180 CSPAD Z-stage |
| 120V AC Power Supply | Power supply for mobile rack electronics |
| Motor Power Supply | Power supply for dumb motors |
When a detector chamber changes locations, such as when DS2 moves from DSD to DSA, the mobile racks are powered down, IOCs disabled, and the detector chamber's external electronics are unplugged. When it is mounted at its new location, the cables need to be reconnected and the mobile rack will need to be set up again and their IOCs restarted. The CXI Home Screen will also need to be edited to draw the control buttons under the correct detector stand location.
IOCs for D50 are running on ioc-cxi-protura1, and IOCs for D51 are on ioc-cxi-protura2.
Shutting Down the Mobile Racks:
- Before turning anything off, disable the IOCs running on the server in the mobile rack. Open
iocmanagerand sort by the "Host" column to list the IOC processes running on the rack's server. Move your attention to the "State" column, and for each IOC select "Off" in its respective cell. When you're done, navigate to the "Configuration" dropdown on the top left and click "Apply". Note this will only work if a PCDS member has given permission to your SLAC UNIX account. You will be prompted to enter your username and password! A pop-up window appear somewhere inconvenient and ask you to confirm your actions. Confirm your actions. Make sure no other changes are being applied. - Powering down the rack should be carried out in the following steps:
Setting Up the Mobile Racks:
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