Difference between revisions of "Compton"

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The Compton polarimeter can be used to non-invasively monitor the beam polarization. It has three major components: an optics table with a laser that can lock to a Fabry-Perot cavity; an electron detector to count scattered electrons; and a photon detector to count scattered photons. At present, the electron detector is in commissioning, so only the photon detector is fully functional.
+
== The Hall A Compton ==
  
There is additional documentation at [http://hallaweb.jlab.org/compton Hall A compton webpage]
+
The Compton polarimeter is used to (non-invasively) monitor polarization of the incoming electron beam.  
 +
It has three major components: an optics table with a laser that can lock to a Fabry-Perot cavity, an electron detector, and a photon detector to count scattered electrons and photons, respectively.
  
=Standard Compton=
+
Last edit: [[User:Lthorne|LThorne]] 02:08, 24 February 2016 (UTC)
  
Monitoring the beam polarization using the Compton polarimeter requires two steps:
+
<!-- Comments -->
 +
<!-- Please replace text after "Last edit: " with "~~~~" when editing relevant section. -->
 +
<!-- Last edit on {{REVISIONYEAR}} {{REVISIONMONTH}} {{REVISIONDAY2}}, by {{REVISIONUSER}} -->
  
*Take Compton data. These can be long runs, but since you can only check the polarization after a run has ended, it is best to start a new run every hour or two. When you end a run, click "Submit" to dismiss the gray pop-up window.
+
== Shift Workers' Operation Guide ==
  
* After a Compton run has analyzed (this takes about 10% the length of the run), check the logbook [1] for the Compton asymmetry.  
+
Start a Compton run every two hours.  
  
If runcontrol shows that it can't communicate with a ROC or if the data won't analyze, stop the current run and type "coda reboot" into a compton@compton terminal window to reboot the ROCs and CODA. If the problem is with ER1, you will need to type
+
The Compton DAQ is located in the back room in the Counting House. All commands are done from compton@compton.  
  
    coda_er -n ER1
+
If CODA is not already running:
  
into a separate window.
+
: Kill CODA first, then start it up again:
  
See below for more details.
+
    $ kcoda
 +
    $ startcoda
  
==Presentation==
+
: A few new Terminal windows and a GUI pop up.
 +
:: [[Image:LT CODAgui.png|800px]]
 +
: Let "top" refer to the bar with named menu options near the top of the GUI (ex: Platform, Sessions, etc). Let "bottom" refer to the bar below "top" that contains a line of buttons (hover over them to reveal their labels; starting with "Configuration" on the left).
 +
:# In top, select: Platform > Connect
 +
:# In bottom, click on "Configuration" button.
 +
:#* If configuration listed in the "Run Parameters" box is not '''FADC_prod''': in top, select Configurations > Cool and change it to '''FADC_Prod'''.
 +
:# In bottom, click on "Download" button
 +
:# In bottom, click on "Prestart" button
 +
:# When ready to start run, click "Start" button. Typical run duration: 2 hours. Type in any Start Of Run comments in the box. Click "OK" (even if you left comments blank!).
 +
:# When ready to stop run, click "End" button. Type in any End Of Run comments in the box. Click "OK" (even if you left comments blank!).
  
The Compton is run from the compton machine, which is the leftmost active monitor in the back room of the Hall A counting room. The login name is compton and the password is the same as the one for the adaq account.
+
== Information for Compton Experts ==
 +
=== Troubleshooting ===
 +
# HV on/off? -> [[Compton#High Voltage Controls]]
 +
# Rebooting components: [[Compton Reboot]]
 +
# [Experts only]: Correct parameters for run in ''integratingDAQ.flags'' and ''compton.params''
  
To begin a new CODA instance, type
+
=== Collimator Systems ===
  
     coda start
+
[[File:Jaws_positions.PNG|thumb|300px|What the jaws look like when placed at their lowest position, as seen on comptcam2. To view this camera follow [http://comptcam2.jlab.org this link] and login with compton credentials.]]
 +
* Primary Lead Collimator
 +
** Presently left fully open at 20 mm diameter.
 +
** This is a 10 cm long collimator with inserts which can reduce aperture down to 10 mm or 5 mm in diameter.
 +
* Synchrotron Shields
 +
** For PREX-II a single 0.25 mm lead foil (painted) is taped to the front of the photon detector.
 +
* Compton Jaws
 +
** Remote access for experts can be found at [http://compjaws.jlab.org]
 +
** Note, for the duration of the PREX-II running period, the Compton Tungsten Collimator System ("Compton Jaws") will not be used. It should be left it is's parked position of:
 +
     aperture =  1.5 mm
 +
    y center = -46.0 mm
  
To recover from a CODA crash, type
+
=== Detector Positioning System ===
  
    coda reboot
+
* Centering Beam & Photon Detector
 +
** Refer to section [[Compton Photon Detector Centering Procedure]] for more info.
 +
* For controls, troubleshooting: [[Compton Photon Detector]]
 +
* Home position of photon detector table:
 +
{| class="wikitable"
 +
! Date
 +
! X [mm]
 +
! Y [mm]
 +
! Comment
 +
|-
 +
| 2019-06-17
 +
| 70
 +
| 33.5
 +
| Visually Centered
 +
<!--
 +
|-
 +
| 2019-XX-XX
 +
| XX
 +
| XX
 +
| XX
 +
-->
 +
|}
  
To open a strip chart, type
+
=== Cameras ===
 +
* [http://comptcam1.jlab.org ComptCam1]: Detector Table
 +
* [http://comptcam2.jlab.org ComptCam2]: Tungsten Jaws
  
    StripTool HappexIIICompton.stp
+
=== High Voltage Controls ===
 +
* [[HV Control GUI]]
 +
** GUI can only be accessed once per person. We share this GUI with Moller Polarimeter.
  
==Operation==
+
=== LED System (Linearity Measurement System) ===
 +
* Will add info on MiniMegan soon
  
To start a run, click the "Start" button in the runcontrol window. After a time, you should see the event count start to go up and the message "Transition Go Succeeded" at the bottom of the screen.
+
'''Taking an LED run:'''
  
To setup the compton trigger parameters use the spyconf program :
+
# Find parameter file GUI:
 +
    $ cd /home/compton/franklin/
 +
    $ ComptonConfig
 +
# Click "Pulser On, Pulser Trigger" on parameter file. Click "Apply", then "Done" to close GUI.
 +
# Go to CODA. Start a new run to apply the settings. (This does not need to be a long run. You may end it immediately.)
 +
# Start your LED run.
 +
# ''When you go back to normal Compton runs: don't forget to turn the pulser off and do a short run to update the parameter file settings!''
  
  spyconf
+
=== Laser System ===
  
[[Image:Spyconf.jpg]]
+
[[Real time o-scope signals]]
  
One can select the different data taking modes in General Daq Setup.
+
[[Cavity lock camera]]
  
On the right panel one can setup the photon detector parameters. We are using only the central crystal only.
+
[[Make sure laser flipping is on]]
  
On the bottom middle pannel, one can setup the electron detectors parameters.
+
[[Turning off the laser]]
  
number of planes needed to generate a trigger
+
[[IOC reboot]]
coincidence time windows between planes
+
number of adjacent strips ored to be looked in the next plane for the trigger
+
  
When it is time to end a run, click the "End Run" button in the runcontrol window. A gray screen should pop up, giving you the opportunity to enter a message (say, if the beam was very trippy). Make sure you dismiss the window by clicking "Submit" -- not "Exit"! Hitting "Submit" sends the run to the analyzer, which is very important.
+
[[Accessing the laser hutch in the hall]]
  
You may additionally get a pop-up window saying "End run failed!" on the runcontrol window. This is okay. Dismiss this popup window and click the "Reset" button on runcontrol. (Yes, despite the dire warning, you really do want to do this.) You should then be able to start the next run.
+
[[Laser and Locking troubleshooting]]
  
While running, you can monitor the beam current, photon rates, cavity status, etc using a strip chart.  Here's what it might look like:
+
== Software & Data Analysis ==
  
[[Image:Transversity_striptool.jpg|800px]]
+
Relevant files, scripts, etc.
  
* Purple line: Beam current (uA). In the figure you can see that it has tripped a few times.
+
'''Run Compton analysis:'''
* Yellow line: Vertical beam position. This should remain roughly constant. A beam trip sends it to the top of the chart (position 0).
+
* Red line: Cavity power. This should be a square wave: the cavity is locked in the right polarization state, then turns off, then locks in the left polarization state, then turns off, then repeats. The powers for the right and left states appear different but are actually the same. The power should stay comfortably above 400 W. (Cavity will not lock during extended beam trips.)
+
* Blue line: Scattered photon rates in the detector. As in the figure, these should track the cavity on/off states; if you can tell from the blue line alone whether the cavity is on or off, then you are probably getting good Compton data.
+
**If this is not the case, this may be due to a bad tune resulting from very low current, or the Compton chicane is off. If one of these is not the cause, contact a Compton expert.
+
**If your blue line is zero or not displaying, there are three possible causes:
+
***Beam trip
+
***HV trip. Check the Beamline HV card 11. Channel 1 should be set to -1800 V for the GSO detector.  If the HV is tripping over and over again, call a Compton expert.
+
***DAQ is not running. Start a CODA run and the blue line should come back. If CODA is already running, it may be in a strange state;
+
end the run and type "coda reboot" into a terminal to restart the ROCs and CODA, then start a new run.
+
  
==Checking a Run==
+
In compton@compton:
Compton analysis results are written to the Compton logbook, which can be accessed onsite at [http://hallaweb.jlab.org/compton/Logbook/]
+
  
Find the run number (newest runs are at the top) and click the '''html''' link. (The pdf link does not work.) This will open a new window with the analysis results.
+
    $ cd /home/compton/online/CompMon
  
The full results will not display right away (because the analyzer does not finish immediately). It takes the analyzer about 10% of the runtime to complete. So an hourlong run will be analyzed after about 6 minutes.
+
Run analysis software:
  
The most important graph is about a third of the way down the page. You can find it quickly by searching the page for "Counting Rates". It's the graph titled '''Asym in ADC bins''':
+
    $ ./compmon <run number, no brackets>
  
[[Image:Compton_asym_graph.jpg]]
+
Open ROOT:  
  
Here are the important things to look for:
+
    $ root -l /data/cmuwork/rootfiles/Fall2016/compmon_<run number, no brackets>.root
  
* The green line (cavity off) should be consistent with zero. This shows that there is no asymmetry in the background.
+
Run desired C script located in CompMon directory.
* The red/blue lines (cavity on, right/left) should be roughly symmetric about zero. This reflects the fact that flipping the cavity polarization changes the sign of the asymmetry. (It's ok for there to be slight differences as above.)
+
* At the extremes (highest/lowest point) we should see an asymmetry greater than about 5%. (Here, we see extremes of about 8% and just over 6% for right and left.) If the asymmetry drops below 3%, we worry. Call an expert.
+
  
==CIP Scan==
 
Getting good data sometimes requires a CIP (Compton interaction point) scan, where the beam tune is adjusted slightly in order to maximize its interaction with the photons in the cavity. Call a Compton expert to perform such a scan if:
 
  
* There has been a new beam tune through the Compton chicane.
+
'''Some useful analysis scripts:'''
* The beam has been shut down for longer than an eight-hour shift.
+
* '''For PREX we should use: ''' <code>/home/compton/online/CompMon/dataQualityCheck.C</code> '''as our online macro!'''
* The photon counting rates drop drastically during steady running. (Compton rate (blue line) in strip chart -- see below)
+
** As of now the way to run it is to navigate to the directory with the file and then running with <code>root -l dataQualityCheck.C\(<run number>,<tests flag>\)</code> We're looking into adding a simplified interface in the near future.
 +
The following macros were maintained by people who no longer work on the compton so use with caution:
 +
* /home/compton/lthorne/CompMon/plotAsymSpectrum.C: Quick and dirty view of asymmetry histograms, cavity and BCM limits.
 +
* /home/compton/lthorne/CompMon/buildQuartets.C and buildQuartetsPlot.C: For constructing multi-run asymmetry plots.
 +
** Run instructions are given in the comments at the beginning fo the file.
 +
* /home/compton/lthorne/CompMon/BCMCal/calibration<runNumber>,C: BCM calibration scripts for specific runs.
 +
* /home/compton/lthorne/CompMon/plotAccQuartets.C: plots sum, difference histograms for beam off, laser on, laser off for Acc0, Acc4.
 +
* /home/compton/franklin/CompMon/plotPulser.C: peek at DAQ pulser channels, including info on 'variable' and 'delta' for channel 13.
  
=Compton Upgrade=
 
  
==Green Fabry-Perot Cavity==
+
'''Link to list of good Compton runs:'''
to be updated soon...
+
  
==Photon detector==
+
List of runs with comments, so know which ones were not junk.
The new photon detector crystal is a cylinder of GSO with a diameter of 6 cm and a length of 15 cm. It was installed in Hall A in December 2008.
+
  
In October 2008, the crystal was tested at incident photon energies of 20 MeV, 22 MeV, 25 MeV, 30 MeV, and 40 MeV. We are working on extracting the response function.
+
DVCS Google Docs: [https://docs.google.com/spreadsheets/d/1gSmgOaJW2azUDhhULDroP4eSpFxkn88YoFsQYNUVS1E/edit?usp=sharing Runlist] (Email Juan Carlos if you want to granted write permission)
 +
PREX-CREX Google Docs: [https://docs.google.com/spreadsheets/d/13SW_Ya0zV5NDWxlS9A5FQ6b9YzpJw2fRNshcWm-noRA/edit?usp=sharing Runlist]  (Email Juan Carlos if you want to granted write permission)
  
PREx requires an integrating DAQ system, which will run on a Struck FADC. We are currently commissioning this DAQ with a prototype FADC.
 
  
===Homing the photon detector table===
 
You need to put the photon detector in the right position before you can take data: [[Happex_compton | How to home the table]]
 
  
===New DAQ flags file controls===
+
<!--  <small>''Last edit: ~~~~''</small> -->
  
The FADC photon detector crl code lives in the franklin/crl directory.  To change the running mode, link a run file to the fadcScaler.flags file.  This is done by deleting the old fadcSclaer.flags file and then creating a link.  To do this, type:
 
  
    rm fadcScaler.flags
+
=== Helicity controls ===
    ln standardRun.flags fadcScaler.flags -s
+
  
There are several different configuration flags filesThese are:
+
From within ''NewTools'' controls (see first few steps in [[Compton Photon Detector]] Compton GUI section):
 +
# On far right of JTabs menu, there are "master" controlsFind and click on Tools Screen.
 +
# Go to the helicity controls.  (The default is delayed, so be careful of this.)
  
    standardRun.flags, for production data
+
=== Current Scripts ===
    Etrigger.flags, for triggering the FADC on the electron detector
+
    miniMegan.flags, for miniMegan LED pulser runs
+
    test.flags, for playing around
+
  
There are several flags which can be changed in the file. These are:
+
As a brief check, run '''plotAsymSpectrum.C'''.
 +
: [[Image:LTRun2565AsymNew.png|700px]]
  
*readoutWaveformLength (number of samples read out per trigger, should be 100 for production data)
+
<!-- <small>''Last edit: [[User:Lthorne|Lthorne]] 16:35, 4 February 2016 (UTC)''</small> -->
*readoutWaveformStart (sample to start read out -- trigger should be near 0, so -50 centers a pulse in a window of 100)
+
*maxStoredWaveforms (number of waveforms stored per MPS)
+
*maxStoredSums (number of sums stored per MPS)
+
*bitPMTtrig (1 means triggering on PMT signal)
+
*bitEDetTrig (1 means triggering on electron detector)
+
*bitPulserTrig (1 mean triggering on 10kHz pulser)
+
*bitMiniMegan (0 means LEDs not flashing, 1 means flashing)
+
*bitDelta (0 means delta LED not flashing, 1 means flashing)
+
*VarDACsetting (0 means variable LED changing pulse amplitude; set it to some value to leave it constant, 35200 corresponds to a 250mV signal on the scope in the counting house)
+
*numADCchan (number of FADC channels read out as sums; generally 1 for the GSO, 3 reads out the fingers also)
+
*prescaleTrig (prescale on the trigger for sums; 1 turns off prescale)
+
*prescaleRand (random prescale on the samples; 0 turns off random prescale, 4 means that every 4 samples is random in time)
+
  
(Courtesy of Megan Friend )
+
== PREX-II/CREX Compton Analysis ==
  
== Portserver assignement ==
+
We've reworked the analysis to streamline finding the most important plots. We've adopted the analysis GUI used by panguin and other online monitors for Hall A experiments. To run, follow the steps below.
  
  cptsv1  20xx
+
=== Online Analysis Steps and Checks ===
  
2 cptaq1
+
# Using the directions at the top of the page, open CODA and start a run.
 +
# Open a terminal and login using <code>ssh -Y compton@compton.jlab.org</code>
 +
# Enter command <code>gocompton</code>
 +
# First run compmon to analyze the run. To this use command <code>./compmon.sh -r <run number></code>
 +
# Once the run is finished analyzing and errors are logged, enter <code>source online.csh -r <run number></code>. This will create the plots in the GUI window.
 +
# Look at the plots in the following tabs:
 +
#* Snapshots: This window has one plot of snapshot peak height vs sum. Plot should look starkly linear. Plot also has the percentage of snapshots that pass an arbitrary selection criteria. I find healthy runs have about 80% of snapshots pass.
 +
#* Spectra: Plots compton spectrum broken down by beam and laser state. Is the compton edge where we expect it to be? Are Brem events low when beam or laser is off?
 +
#* Acc0: Plots of accumulator 0. Are they gaussian? Does the mean of the beam ON, laser ON plot differ from all the others?
 +
#* Acc0 vs Time: Plots of accumulator 0 value vs mps number. Are the accumulator values drifting significantly with time?Are beam trips readily noticeable?
 +
#* Asym and Polarization: Includes plots of the quartet sums, differences and asymmetry. Do they all look roughly gaussian? Are there no double-peaking effects? Does the calculated polarization yield some reasonable value?
 +
#* Asyms vs Time: Plots of the above vs time. Is there any significant drift in any of the quantities vs time?
 +
#* Asym Spectrum: '''As of 2019-07-31 this plot is not working. Background subtraction needs to be more carefully refined.'''
 +
# Once you click "Exit GUI" the same plots will be generated and saved to the [http://hallaweb.jlab.org/parity/prex/onlinePlots/comptonPlots compton plots web page] for easy review.
  
3 cptaq2
+
=== Making Custom Plots ===
 +
There are macros which make other compton plots which have been useful in the past, but are not being maintained anymore. To be certain, you can make your own plots to slake your curiosity. The following is description of CompMon output, the branches, as well as certain variables which you may find useful.
  
4 cptaq4
+
* General Variables: These variables may be found stored in multiple trees and should come in handy:
 +
** helicityStateReported: 0 for negative, 1 for positive
 +
** laserState: 0 for right-hand polarization and laser on, 1 for left-hand polarization and laser on, 2 for right hand polarization and laser off, 3 for left hand polarization and laser off, 4 for unknown state
 +
** beamState: 0 for beam off, 1 for beam on, 2 for unknown beam state.
 +
** cavPowerCalibrated: laser cavity power
 +
** bcm: calibrated BCM signal
 +
* mpswise: A tree of data stored per MPS
 +
** mpsCoda: MPS number
 +
** Acc#: Accumulator total for number #
 +
** NAcc#: Number of accumulator samples per MPS for accumulator number #
 +
** numTriggers: Number of triggered sums in current MPS
 +
* triggerwise: A tree of variables stored per trigger
 +
** sum: Total sum of trigger
 +
** sumIsRandom: 0 if sum is real, 1 if it is random
 +
* quartetwise: A tree of variables stored per quartet
 +
** PosHelAcc#: Sum of accumulator number # for positive helicity states in the quartet
 +
** PosHelNSamples#: Number of samples for accumulator number # for positive helicity states in the quartet
 +
** NegHelAcc#: Sum of accumulator number # for negative helicity states in the quartet
 +
** NegHelNSamples#: Number of samples for accumulator number # for negative helicity states in the quartet
 +
** quartetReportedHelicityPattern: Two different values, one for each valid quartet pattern
 +
* snapshots: A list of variables and snapshot readouts for each snapshot taken
 +
** numSamples: Number of samples in snapshots
 +
** snap: An array variable with numSamples entries that details the fADC readout of the snapshot
 +
* pulserwise: A tree of variables stored per pulser cycle. (SHOULD ONLY BE NEEDED BY EXPERTS)
 +
* runwise: A tree of variables stored per run. This tree only has one entry per leaf, and details info about pedestals.
 +
* epicswise: A tree of variables taken per EPICS event. These variables are also stored in other trees, so they can be accessed from there.
  
5 cptaq5
+
This is in addition to the inbuilt histograms produced in every CompMon output file. This should be more than enough to diagnose any compton DAQ problems.
+
6 cptps1
+
+
7 cptps2 ( RPC5 ROC1 on port 1 and ROC2 on port 2)
+
  
8 iochacp
+
== Compton Meetings ==
  
9  
+
See last list entry for most recent meeting.
 +
* [[Meetings before 2014]]
 +
* [[2014 Meetings]]
 +
* [[2015 Meetings]]
 +
* [[2016 Meetings]]
 +
* [[2017 Meetings]]
 +
* [[2018 Meetings]]
 +
* [[Wednesday, January 9, 2019, 11:00 am EST - Compton]]
 +
* [[Wednesday, January 23, 2019, 11:00 am EST - Compton]]
 +
* [[Wednesday, February 6, 2019, 11:00 am EST - Compton]]
 +
* [[Wednesday, February 27, 2019, 11:30 am EST - Electron Detector]]
 +
* [[Wednesday, March 20, 2019, 11:00 am EST]]
 +
* [[Wednesday, April 17, 2019, 11:00 am EDT]]
 +
* [[Wednesday, May 1, 2019, 11:00 am EDT]]
 +
* [[Wednesday, May 8, 2019, 11:00 am EDT]]
 +
* [[Wednesday, May 22, 2019, 11:00 am EDT]]
 +
* [[Wednesday, May 29, 2019, 11:00 am EDT]]
 +
* [[Wednesday, June 5, 2019, 11:00 am EDT]]
 +
* [[Wednesday, June 12, 2019, 2:30 pm EDT]]
 +
* [[Wednesday, August 14, 2019, 11:00 am EDT]]
 +
* [[Wednesday, August 21, 2019, 11:00 am EDT]]
 +
* [[Thursday, August 22, 2019, 11:00 am EDT _ Electron detector]]
 +
* [[Wednesday, August 28, 2019, 10:00 am EDT]]
 +
* [[Wednesday, September 4, 2019, 10:00 am EDT]]
 +
* [[Wednesday, September 11, 2019, 11:00 am EDT]]
 +
* [[Thursday, September 19, 2019, 11:00 EDT]]
 +
* [[Wednesday, October 2, 2019, 11:00 EDT]]
 +
* [[Wednesday, October 9, 2019, 11:00 EDT]]
  
10 iochacp2
+
== Current Compton Experts ==
+
11  TS crate
+
 
+
12
+
 
+
== FADC DAQ ==
+
We are commissioning a new FADC-based DAQ for the photon detector. See [[Compton FADC DAQ|run information]].
+
 
+
[[Compton analysis (for experts)|Help with analyzing data from the FADC DAQ]]
+
 
+
==Electron detector==
+
 
+
[http://spreadsheets.google.com/pub?key=p21FHudpawOtOCa6JDWdMfA Detector new event structure]
+
 
+
Webcams address
+
 
+
Webcams were added to monitor the :
+
 
+
*hacp2 [http://hacp2.jlab.org EthernetBlaster]
+
*hacp3 [http://hacp3.jlab.org webcam trigger]
+
*hacp4 [http://hacp4.jlab.org webcam on Beam Safety module, Front End power supply] 
+
*hacp5 [http://hacp5.jlab.org webcam on silicon strips detector current]
+
*hacp6 [http://hacp6.jlab.org APC]
+
** plug 1 Front End power supply
+
** plug 2
+
** plug 3
+
** plug 4 Webcam current
+
** plug 5
+
** plug 6 Ligh for viewer
+
** plug 7
+
** plug 8 Light for cameras
+
 
+
 
+
How to reboot stuffs
+
 
+
APC : [http://hareboot4 hareboot4]
+
 
+
*plug 2 webcam
+
*plug 3 EPICS Edet
+
*plug 4 ETROC
+
*plug 5 ts crate
+
*plug 6 FADC crate
+
 
+
 
+
login hareboot4 using the usual password ( if you don't know it ask the run coordinator or a Compton expert )
+
 
+
select the outlet you want to reboot with the pull down menu "Immediate reboot"
+
 
+
and wait for the IOC to come back
+
 
+
 
+
====IOC iochacp2 boot parameters ==
+
 
+
boot device          : dc
+
unit number          : 0
+
processor number    : 0
+
host name            : eosfs
+
file name            : /eossite/op/iocs/iochacp2/vx/vxWorks.st
+
inet on ethernet (e) : 129.57.242.16:fffffc00
+
host inet (h)        : 129.57.240.60
+
user (u)            : vxwrks
+
flags (f)            : 0x80
+
target name (tn)    : iochacp2
+
startup script (s)  : /eossite/op/iocs/iochacp2/startup
+
 
+
 
+
===Electron detector signals on patch panel ===
+
 
+
Output  cable  patch
+
2        48    24     
+
5(5)      79    10
+
6(6)      56    20
+
7(7)            25
+
Analog            24
+
Analog            26
+
 
+
N6-38L Plan A ch 96 left
+
N7-39L Plan A ch 96 right
+
 
+
===Electron detector input signals ===
+
 
+
0 P0  Half of helicity flip frequency
+
 
+
1 P1  Helicity
+
 
+
2 P2  Laser on/off
+
+
3 P3  Laser helicity
+
 
+
4 Laser helicity inverted
+
 
+
5 MPS
+
 
+
6 Clear
+
+
7 Photon from integrating
+
 
+
===Electron detector motion===
+
 
+
[[Compton Edet DAQ]]
+
 
+
=Compton Meetings=
+
* [[Friday, December 7, 2012 11am EST - Compton]]
+
* [[Monday, January 14, 2013 1pm EST - Compton]]
+
* [[Tuesday, February 12, 2013 3pm EST - Compton]]
+
* [[Thursday, March 28, 2013 1pm EST - Compton]]
+
* [[Wednesday, May 1, 2013 2pm EST - Compton]]
+
* [[Thursday, September 26, 2013 2pm EST - Compton]]
+
* [[Thursday, November 14, 2013 2pm EST - Compton]]
+
* [[Tuesday, December 10, 2013 11am EST - Compton]]
+
* [[Thursday, February 27, 2014 2:30pm EST - Compton]]
+
* [[Friday, April 4, 2014 2:00pm EDT - Compton]]
+
* [[Thursday, May 21, 2015, 11:00am EDT - Compton]]
+
* [[Thursday, June 4, 2015, 11:00am EDT - Compton]]
+
* [[Thursday, July 2, 2015, 11:00am EDT - Compton]]
+
* [[Thursday, July 23, 2015, 11:00am EDT - Compton]]
+
* [[Thursday, August 6, 2015, 11:00am EDT - Compton]]
+
* [[Thursday, September 3, 2015, 11:00am EDT - Compton]]
+
 
+
=Compton Experts=
+
  
 
{| class="wikitable"
 
{| class="wikitable"
Line 291: Line 264:
 
! Expert
 
! Expert
 
! Phone
 
! Phone
! Pager
 
 
|-
 
|-
 
| Dave Gaskell
 
| Dave Gaskell
Line 300: Line 272:
 
|-
 
|-
 
| Ciprian Gal  
 
| Ciprian Gal  
|  
+
| x5324
|}
+
 
+
=Past Compton Experts=
+
{| class="wikitable"
+
 
|-
 
|-
! Expert
+
| Juan Carlos Cornejo (Photon Detector)  
! Phone
+
| x5282
! Pager
+
|-
+
| Sirish Nanda
+
|-
+
| Abdurahim Rakhman
+
| x5626 (Lab) 
+
| 315-391-4622 (cell)
+
|-
+
| Megan Friend
+
| 412-302-0576 (cell)
+
|  
+
 
|}
 
|}
 +
 +
== Expert Information ==
 +
For expert monitoring and troubleshooting information please visit [[Compton Expert Information]].
 +
 +
== Analyzer ==
 +
Code can be found on github: https://github.com/JeffersonLab/HallA_CompMon
 +
JC says:
 +
The Makefile is ancient (since it has to work on old systems too) but there is an easy "fix".  In the src/config.d directory, create a file similar to cornejo_compton_jlab.conf but modify the paths respectively.
 +
Then run ./config config.d/<your_config_file>
 +
It will update the silly Makefile accordingly
 +
 +
Some old data and examples can be found on
 +
/w/halla-scifs17exp/compton/disk1/data/examples
 +
 +
== Old Compton page (pre-Spring 2016) ==
 +
 +
See [[Pre-Spring 2016 Compton]]
 +
 +
 +
Last edit on {{REVISIONYEAR}} {{REVISIONMONTH}} {{REVISIONDAY2}}, by {{REVISIONUSER}}

Latest revision as of 14:53, 8 October 2019

The Hall A Compton

The Compton polarimeter is used to (non-invasively) monitor polarization of the incoming electron beam. It has three major components: an optics table with a laser that can lock to a Fabry-Perot cavity, an electron detector, and a photon detector to count scattered electrons and photons, respectively.

Last edit: LThorne 02:08, 24 February 2016 (UTC)


Shift Workers' Operation Guide

Start a Compton run every two hours.

The Compton DAQ is located in the back room in the Counting House. All commands are done from compton@compton.

If CODA is not already running:

Kill CODA first, then start it up again:
   $ kcoda
   $ startcoda
A few new Terminal windows and a GUI pop up.
LT CODAgui.png
Let "top" refer to the bar with named menu options near the top of the GUI (ex: Platform, Sessions, etc). Let "bottom" refer to the bar below "top" that contains a line of buttons (hover over them to reveal their labels; starting with "Configuration" on the left).
  1. In top, select: Platform > Connect
  2. In bottom, click on "Configuration" button.
    • If configuration listed in the "Run Parameters" box is not FADC_prod: in top, select Configurations > Cool and change it to FADC_Prod.
  3. In bottom, click on "Download" button
  4. In bottom, click on "Prestart" button
  5. When ready to start run, click "Start" button. Typical run duration: 2 hours. Type in any Start Of Run comments in the box. Click "OK" (even if you left comments blank!).
  6. When ready to stop run, click "End" button. Type in any End Of Run comments in the box. Click "OK" (even if you left comments blank!).

Information for Compton Experts

Troubleshooting

  1. HV on/off? -> Compton#High Voltage Controls
  2. Rebooting components: Compton Reboot
  3. [Experts only]: Correct parameters for run in integratingDAQ.flags and compton.params

Collimator Systems

What the jaws look like when placed at their lowest position, as seen on comptcam2. To view this camera follow this link and login with compton credentials.
  • Primary Lead Collimator
    • Presently left fully open at 20 mm diameter.
    • This is a 10 cm long collimator with inserts which can reduce aperture down to 10 mm or 5 mm in diameter.
  • Synchrotron Shields
    • For PREX-II a single 0.25 mm lead foil (painted) is taped to the front of the photon detector.
  • Compton Jaws
    • Remote access for experts can be found at [1]
    • Note, for the duration of the PREX-II running period, the Compton Tungsten Collimator System ("Compton Jaws") will not be used. It should be left it is's parked position of:
   aperture =   1.5 mm
   y center = -46.0 mm

Detector Positioning System

Date X [mm] Y [mm] Comment
2019-06-17 70 33.5 Visually Centered

Cameras

High Voltage Controls

  • HV Control GUI
    • GUI can only be accessed once per person. We share this GUI with Moller Polarimeter.

LED System (Linearity Measurement System)

  • Will add info on MiniMegan soon

Taking an LED run:

  1. Find parameter file GUI:
   $ cd /home/compton/franklin/
   $ ComptonConfig
  1. Click "Pulser On, Pulser Trigger" on parameter file. Click "Apply", then "Done" to close GUI.
  2. Go to CODA. Start a new run to apply the settings. (This does not need to be a long run. You may end it immediately.)
  3. Start your LED run.
  4. When you go back to normal Compton runs: don't forget to turn the pulser off and do a short run to update the parameter file settings!

Laser System

Real time o-scope signals

Cavity lock camera

Make sure laser flipping is on

Turning off the laser

IOC reboot

Accessing the laser hutch in the hall

Laser and Locking troubleshooting

Software & Data Analysis

Relevant files, scripts, etc.

Run Compton analysis:

In compton@compton:

   $ cd /home/compton/online/CompMon

Run analysis software:

   $ ./compmon <run number, no brackets>

Open ROOT:

   $ root -l /data/cmuwork/rootfiles/Fall2016/compmon_<run number, no brackets>.root

Run desired C script located in CompMon directory.


Some useful analysis scripts:

  • For PREX we should use: /home/compton/online/CompMon/dataQualityCheck.C as our online macro!
    • As of now the way to run it is to navigate to the directory with the file and then running with root -l dataQualityCheck.C\(<run number>,<tests flag>\) We're looking into adding a simplified interface in the near future.

The following macros were maintained by people who no longer work on the compton so use with caution:

  • /home/compton/lthorne/CompMon/plotAsymSpectrum.C: Quick and dirty view of asymmetry histograms, cavity and BCM limits.
  • /home/compton/lthorne/CompMon/buildQuartets.C and buildQuartetsPlot.C: For constructing multi-run asymmetry plots.
    • Run instructions are given in the comments at the beginning fo the file.
  • /home/compton/lthorne/CompMon/BCMCal/calibration<runNumber>,C: BCM calibration scripts for specific runs.
  • /home/compton/lthorne/CompMon/plotAccQuartets.C: plots sum, difference histograms for beam off, laser on, laser off for Acc0, Acc4.
  • /home/compton/franklin/CompMon/plotPulser.C: peek at DAQ pulser channels, including info on 'variable' and 'delta' for channel 13.


Link to list of good Compton runs:

List of runs with comments, so know which ones were not junk.

DVCS Google Docs: Runlist (Email Juan Carlos if you want to granted write permission) PREX-CREX Google Docs: Runlist (Email Juan Carlos if you want to granted write permission)



Helicity controls

From within NewTools controls (see first few steps in Compton Photon Detector Compton GUI section):

  1. On far right of JTabs menu, there are "master" controls. Find and click on Tools Screen.
  2. Go to the helicity controls. (The default is delayed, so be careful of this.)

Current Scripts

As a brief check, run plotAsymSpectrum.C.

LTRun2565AsymNew.png


PREX-II/CREX Compton Analysis

We've reworked the analysis to streamline finding the most important plots. We've adopted the analysis GUI used by panguin and other online monitors for Hall A experiments. To run, follow the steps below.

Online Analysis Steps and Checks

  1. Using the directions at the top of the page, open CODA and start a run.
  2. Open a terminal and login using ssh -Y compton@compton.jlab.org
  3. Enter command gocompton
  4. First run compmon to analyze the run. To this use command ./compmon.sh -r <run number>
  5. Once the run is finished analyzing and errors are logged, enter source online.csh -r <run number>. This will create the plots in the GUI window.
  6. Look at the plots in the following tabs:
    • Snapshots: This window has one plot of snapshot peak height vs sum. Plot should look starkly linear. Plot also has the percentage of snapshots that pass an arbitrary selection criteria. I find healthy runs have about 80% of snapshots pass.
    • Spectra: Plots compton spectrum broken down by beam and laser state. Is the compton edge where we expect it to be? Are Brem events low when beam or laser is off?
    • Acc0: Plots of accumulator 0. Are they gaussian? Does the mean of the beam ON, laser ON plot differ from all the others?
    • Acc0 vs Time: Plots of accumulator 0 value vs mps number. Are the accumulator values drifting significantly with time?Are beam trips readily noticeable?
    • Asym and Polarization: Includes plots of the quartet sums, differences and asymmetry. Do they all look roughly gaussian? Are there no double-peaking effects? Does the calculated polarization yield some reasonable value?
    • Asyms vs Time: Plots of the above vs time. Is there any significant drift in any of the quantities vs time?
    • Asym Spectrum: As of 2019-07-31 this plot is not working. Background subtraction needs to be more carefully refined.
  7. Once you click "Exit GUI" the same plots will be generated and saved to the compton plots web page for easy review.

Making Custom Plots

There are macros which make other compton plots which have been useful in the past, but are not being maintained anymore. To be certain, you can make your own plots to slake your curiosity. The following is description of CompMon output, the branches, as well as certain variables which you may find useful.

  • General Variables: These variables may be found stored in multiple trees and should come in handy:
    • helicityStateReported: 0 for negative, 1 for positive
    • laserState: 0 for right-hand polarization and laser on, 1 for left-hand polarization and laser on, 2 for right hand polarization and laser off, 3 for left hand polarization and laser off, 4 for unknown state
    • beamState: 0 for beam off, 1 for beam on, 2 for unknown beam state.
    • cavPowerCalibrated: laser cavity power
    • bcm: calibrated BCM signal
  • mpswise: A tree of data stored per MPS
    • mpsCoda: MPS number
    • Acc#: Accumulator total for number #
    • NAcc#: Number of accumulator samples per MPS for accumulator number #
    • numTriggers: Number of triggered sums in current MPS
  • triggerwise: A tree of variables stored per trigger
    • sum: Total sum of trigger
    • sumIsRandom: 0 if sum is real, 1 if it is random
  • quartetwise: A tree of variables stored per quartet
    • PosHelAcc#: Sum of accumulator number # for positive helicity states in the quartet
    • PosHelNSamples#: Number of samples for accumulator number # for positive helicity states in the quartet
    • NegHelAcc#: Sum of accumulator number # for negative helicity states in the quartet
    • NegHelNSamples#: Number of samples for accumulator number # for negative helicity states in the quartet
    • quartetReportedHelicityPattern: Two different values, one for each valid quartet pattern
  • snapshots: A list of variables and snapshot readouts for each snapshot taken
    • numSamples: Number of samples in snapshots
    • snap: An array variable with numSamples entries that details the fADC readout of the snapshot
  • pulserwise: A tree of variables stored per pulser cycle. (SHOULD ONLY BE NEEDED BY EXPERTS)
  • runwise: A tree of variables stored per run. This tree only has one entry per leaf, and details info about pedestals.
  • epicswise: A tree of variables taken per EPICS event. These variables are also stored in other trees, so they can be accessed from there.

This is in addition to the inbuilt histograms produced in every CompMon output file. This should be more than enough to diagnose any compton DAQ problems.

Compton Meetings

See last list entry for most recent meeting.

Current Compton Experts

Expert Phone
Dave Gaskell x6092
Alexandre Camsonne x5064
Ciprian Gal x5324
Juan Carlos Cornejo (Photon Detector) x5282

Expert Information

For expert monitoring and troubleshooting information please visit Compton Expert Information.

Analyzer

Code can be found on github: https://github.com/JeffersonLab/HallA_CompMon JC says:

The Makefile is ancient (since it has to work on old systems too) but there is an easy "fix".  In the src/config.d directory, create a file similar to cornejo_compton_jlab.conf but modify the paths respectively. 
Then run ./config config.d/<your_config_file> 
It will update the silly Makefile accordingly

Some old data and examples can be found on

/w/halla-scifs17exp/compton/disk1/data/examples

Old Compton page (pre-Spring 2016)

See Pre-Spring 2016 Compton


Last edit on 2019 10 08, by Gaskelld