Overview
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.
Detector Chamber Motors
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
,
we find the motors are for alignment stages, X-Ray focusing optics, a pulse picker, attenuator and more. Excluding the In-Vacuum LS-180, these are all IMS "smart" motors.
Control Screens
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.
Mobile Rack Vertical Layout
1 | CSPAD Concentrator | Handles CSPAD data readout |
2 | Detector PDU | Consolidates power from MPOD with other analog control and timing signals to detector input |
3 | MPOD | EPICS controllable High/Low voltage power supply for detectors |
4 | EPICS IOC Server | IOC for motors, encoders and power supplies running from the mobile rack |
5 | Digi Serial Port Server | Serial communication input/output terminal |
6 | Dumb Motor Controller | For in-vacuum LS-180 CSPAD Z-stage |
7 | 120V AC Power Supply | Power supply for mobile rack electronics |
8 | Motor Power Supply | Power supply for dumb motors |
Mobile Rack Hosts
Mobile Rack | IOC Server Hostname | Digi Hostname |
---|---|---|
D50 | ioc-cxi-protura1 | digi-cxi-21 |
D51 | ioc-cxi-protura2 | digi-cxi-31 |
IOCs running on the mobile rack servers can be found using iocmanager
. If you like terminals, use psproc
.
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 the chamber is mounted at its new location, the cables need to be reconnected and its mobile rack will need to be set up again and the IOCs restarted. The CXI Home Screen will also need to be edited to draw the control buttons under the correct detector stand location.
Shutting Down a Mobile Rack
PCDS OR BEAMLINE EXPERT ONLY. Don't even try it unless you have permission from the CXI controls POC or area manager.
- Before turning anything off, disable the IOCs running on the server in the mobile rack.
- Open
iocmanager
and 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.
- Navigate to the "Configuration" dropdown on the top left and click "Apply". This will only work if your UNIX account has CXI iocmanager privileges. 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..
- Open
- Powering down the rack should be carried out in the following steps:
- Make sure the detectors are powered down via EPICS.
- Go to the rack and power down each module chassis using its front or real panel power button/switch if it has one.
- Switch off the surge protectors on the rear side of the rack.
- Unplug the surge protectors from the stand power outlets.
- Carefully disconnect the grounding cable and CSPAD trunk cable TOP and BOTTOM connectors from the detector chamber flange using a hex wrench. The pins of these connectors are fragile. Disconnect motor and vacuum gauge cables from points J1→J7 on the I/O panel mounted to the detector stand. Keep the cables connected to their interfaces on the rack itself as they will be needed again.
- Look down. There are a few ethernet cables running from the rack to a patch panel beneath the detector stand. These are for connecting the rack's electronics to the CXI controls network. Disconnect them from the patch panel.
- There are a number of BNC cables and multimode fibers running from the CSPAD concentrator and detector PDU to nearby patch panels. These are for detector timing and data and go to servers elsewhere in the hutch. Disconnect them from the patch panel.
- Disconnect the copper grounding cable attached to the bottom of the rack.
Setting Up a Mobile Rack
PCDS OR BEAMLINE EXPERT ONLY.
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- Avada kedavra
Detector and Chamber Troubleshooting
First refer to the CSPAD and PGP troubleshooting guide and DAQ troubleshooting guide for detector related problems. These should sort things out or help narrow down the problem. If you're still stuck, consider the troubleshooting options below: