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 in independent data streams – 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,

DS1 Motor Descriptions 
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
DS2 Motor Descriptions 
cxi-control:~> echo -e "Motor PV\t\t\tDescription:"; caget CXI:DS2:MMS:{01..07}.DESC 
Motor PV 					Description: 
CXI:DS2:MMS:01.DESC 		X US North Lift 
CXI:DS2:MMS:02.DESC 		Y US North Lift 
CXI:DS2:MMS:03.DESC 		Y US South Lift 
CXI:DS2:MMS:04.DESC 		X DS Lift 
CXI:DS2:MMS:05.DESC 		Y DS Lift 
CXI:DS2:MMS:06.DESC 		In-Vacuum LS-180 
CXI:DS2:MMS:07.DESC 		Beamstop Y

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 their name 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

1CSPAD ConcentratorHandles CSPAD data readout
2Detector PDUConsolidates power from MPOD with other control and timing signals to detector input
3MPODEPICS controllable High/Low voltage power supply for detectors
4EPICS IOC ServerIOC for motors, encoders and power supplies running from the mobile rack
5Digi Serial Port ServerSerial communication input/output terminal
6Dumb Motor ControllerFor in-vacuum LS-180 CSPAD Z-stage
7120V AC Power SupplyPower supply for mobile rack electronics
8Motor Power SupplyPower supply for dumb motors

Mobile Rack Hosts

Mobile RackIOC Server HostnameDigi Hostname
D50ioc-cxi-protura1digi-cxi-21
D51ioc-cxi-protura2digi-cxi-31

IOCs running on the mobile rack servers can be found using iocmanager.  If you like terminals, use psproc.

IOC List Command Line Example 
cxi-control:~> psproc ioc-cxi-protura1
PID   USER      SIOC                      COMMAND   HOSTNAME            PORT
3867  cxiioc    caRepeater                procServ  ioc-cxi-protura1    30000
4018  cxiioc    ioc-cxi-mmc-tst           procServ  ioc-cxi-protura1    34431
4020  cxiioc    ioc-cxi-ds1-ims           procServ  ioc-cxi-protura1    32520
4022  cxiioc    ioc-cxi-ds1-stand-ims     procServ  ioc-cxi-protura1    32519
4219  cxiioc    ioc-cxi-mpod-d51          procServ  ioc-cxi-protura1    30301
4379  cxiioc    ioc-cxi-d51               procServ  ioc-cxi-protura1    30101
4485  cxiioc    ioc-cxi-agilent           procServ  ioc-cxi-protura1    33632
4487  cxiioc    ioc-cxi-protura           procServ  ioc-cxi-protura1    30060

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. 

  1. Before turning anything off, disable the IOCs running on the server in the mobile rack.  
    1. Open iocmanager and sort by the "Host" column to list the IOC processes running on the rack's server.  
    2. Move your attention to the "State" column, and for each IOC select "Off" in its respective cell.  
    3. 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.  
    4. Confirm your actions..

  2. Powering down the rack should be carried out in the following steps:
    1. Make sure the detectors are powered down via EPICS.
    2. Go to the rack and power down each module chassis using its front or real panel power button/switch if it has one. 
    3. Switch off the surge protectors on the rear side of the rack.  
    4. Unplug the surge protectors from the stand outlets on the stand.

  3. Remove the grounding cable and carefully disconnect the 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.  


  4. 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.

  5. 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.

  6. Disconnect the copper grounding cable attached to the bottom of the rack.

Setting Up a Mobile Rack

PCDS OR BEAMLINE EXPERT ONLY. 

The process of setting up the mobile rack is essentially the same process as tearing it down in reverse.  Note that these instructions operate under the assumption that the controls signal routing infrastructure is in such a state that plugging devices into IO panels will just "work".  In practice, routing gets mixed up and some patches may not work as expected.  If things aren't working right, check with your controls doctor.

  1. Connect the copper grounding cable to the bottom of the rack.
  2. Below the detector stand is a patch panel for data fibers, RJ45 ethernet cables, BNC triggers, and gauge power and ion current lines.  Connect the ethernet cables from the mobile rack to the RJ45 points on the patch panel.  Any points – it doesn't matter.  The data fibers from the CSPAD concentrator, however, must go to the corresponding fiber patch points with matching labels (eg. RC0, RC1, EVR).  In order to operate CSPAD140k detectors, the detector PDU requires two BNC triggers.  Connect the "DAQ-Trig In" point on the PDU to the patch point labeled "DAQ" and the "Run-Trig In" PDU point to "CNTRL" on the patch panel.  On the CSPAD Concetrator, the "Trig In" is used to trigger the large CSPAD2.3M in the detector chamber.  Some BNC connectors on the detector station patch panels are labeled to indicate which EVR channel it is propagating.  The CSPAD trigger needs to be connected to the BNC point that matches the EVR channel designated to the CSPAD in the CXI DAQ configuration file (/reg/g/pcds/dist/pds/cxi/scripts/{cxi_0.cnf,cxi_1.cnf}).
  3. Connect the motor cables to the detector stand IO panel.  Use the CAPTAR tags on the cables to identify which junction points each cable should be connected.
  4. Carefully connect the CSPAD trunk cable to the detector chamber flange.  The pins for these connectors are fragile.
  5. Plug the power-strips on the side of the rack into 120V outlets on the beamline.  If you plug them into other power-strips, Matt Hayes will find out and revoke your privilege to use electricity at SLAC. He can do that. 
  6. Turn everything in the rack on.
  7. Enable the IOCs using iocmanager.

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.

 


 

 

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