Difference between revisions of "CommissioningPlan"

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<li> Accelerator will establish beam straight to the dump and use this straight trajectory to find BPM offsets.
 
<li> Accelerator will establish beam straight to the dump and use this straight trajectory to find BPM offsets.
 
   Accelerator will ramp up the SBS and corrector magnets.   
 
   Accelerator will ramp up the SBS and corrector magnets.   
−
<li> Harp scans now done to measure beam intrinsic spot size >320um in x and y ([https://sbs.jlab.org/wiki/index.php/Harp_Scans_for_Checking_Beam_Spot_Size_on_Target| spreadsheet]).
+
<li> Harp scans now done to measure beam intrinsic spot size >320um in x and y ([https://sbs.jlab.org/wiki/index.php/Harp_Scans_for_Checking_Beam_Spot_Size_on_Target] ).
−
<li> <b><FONT Color="Green"> Call Zeke </FONT></b> to let him know you are ready for GEMs so that foil z positions can be resolved.
+
<li> <b><FONT Color="Green"> Call Sean </FONT></b> to let him know you are ready for GEMs so that foil z positions can be resolved.
 
<li> BB is now ramped up (see the [https://sbs.jlab.org/wiki/index.php/HOW_TOs#Procedure_for_Ramping_the_BigBite_Magnet procedure]) and Preshower, Shower (collectively BB CAL), and Hodoscope HV is <FONT Color="Green">ON</FONT>.  
 
<li> BB is now ramped up (see the [https://sbs.jlab.org/wiki/index.php/HOW_TOs#Procedure_for_Ramping_the_BigBite_Magnet procedure]) and Preshower, Shower (collectively BB CAL), and Hodoscope HV is <FONT Color="Green">ON</FONT>.  
 
<li> Carbon target foil with 1mm hole inserted and imaged. Position of beam verified and raster size calibrated.  
 
<li> Carbon target foil with 1mm hole inserted and imaged. Position of beam verified and raster size calibrated.  
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</ol>
 
</ol>
  
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=== BB and SBS Commissioning===
+
== BB and SBS Commissioning==
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At this point we have good beam and characterized beam monitors and are ready to commission our experiment using Carbon foils
+
At this point we have good beam and characterized beam monitors and are ready to commission our experiment.
 +
*This segment begins using Carbon foils and BB On (700A) with SBS OFF. Raster will be on.
 +
*<b><FONT Color="Green"> Call system experts</FONT></b>: BigBite (Provakar), HCal (Jiwan), GEMs (Andrew, Holly, Zeke)
 +
There are two parts to this plan:
 
<ol>
 
<ol>
−
<li> <b><FONT Color="Green"> Call system experts</FONT></b>: BigBite (Provakar), HCal (Jiwan), GEMs (Zeke)
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<li> Commissioning detectors, optimizing DAQ+replay, setting thresholds and HV, timing the coincidence trigger
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<li> Ensure the target is empty/OUT of the beam path.  BigBite and SBS magnets are at zero field.
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<li> Taking optics data. This will require transitioning to the glass cells.
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<li> First MCC centers the beam on the differential pumping (DP) apertures (0.75") and then delivers to the beam dump using the dump viewer.
+
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<!-- <li> Slowly turn on SBS magnet and re-establish to dump using correctors with 5 uA of tune beam. (MCC has written procedure for this) -->
+
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<!-- <li> Ramp up BigBite (see [https://sbs.jlab.org/wiki/index.php/HOW_TOs#Procedure_for_Ramping_the_BigBite_Magnet procedure]) -->
+
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<li> Determine the intrinsic beam spot size by performing a HARP scan. Ask MCC to take harp scans on Harps A and B (IHA1H04A and IHA1H04B) and ask them to post the results to our logbook Halog. When the results arrive fill in the green blanks in "Beam spot size at target" section of this [https://docs.google.com/spreadsheets/d/1V6EVndkpJ49YdYLHeQHK3y5Om-U8VKttubZwHNPTPl4/edit#gid=0 spreadsheet]  and report/halog the values of the spot size calculated which show up in the red blanks. If the average of the Xsigma and Ysigma spot radii (1 sigma) is significantly less than 100 microns. Call the RC and ask what to do. We take a run simultaneously (not necessary, but helpful).  <FONT Color="Red">Compare BPM EPICS readings to HARP locations. Steps + script?</FONT>
+
−
<li> Ion chamber calibration on empty target position.  This calibrates the dump ion chambers. 
+
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<li> Ion chamber calibration on Optics 5-foil target.  This calibrates the ion chamber at the target for our optics program.
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<!-- <li> Establish 1 uA CW beam  -->
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<li> Establish nominal 4x4 rastered beam. 
+
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<li> Call MCC to stop the beam and request to move to the Carbon Hole (2-mm) target into the nominal beam path
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<li> Call MCC to request 1 uA of 4x4 rastered beam. Run the DAQ to take data. Analyze the data and produce raster X/Y plots by running the command <code>spot_pp [run_number] [height] [width]</code> from the <code>a-onl@aonl2</code> account, where height and width are the raster size in MCC units. 
+
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<li> Using the 2mm hole in the X,Y raster plot to calibrate the size of the raster and position of the hole.  Iterate with MCC to center beam on the raster pattern by requesting beam position movements on the harps 1H04A and 1H04E.  To calibrate the size of the raster, change the raster size until the X/Y raster plot is about twice the size of the hole. You should now have a beam centered on the target and a 4x4 raster. Record the positions as the new target lock location.
+
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<li> Ask MCC to set the raster to 2mmx2mm by dividing the 4mmx4mm units by 2.  Take a new run to verify that the Carbon hole fills out the entirety of the plot produced by the <code>spot_pp</code> program.  Record these values as the calibrated raster set units.
+
 
</ol>
 
</ol>
  
−
<!-- <FONT Color="Red">Indicate expert(s) for each steps (e.g., DF)</FONT> -->
+
=== Detector Commissioning Program ===  
−
<!-- <FONT Color="Red">What is the max we can get here? Can we get this to 2--4?  BW: 1 uA should be sufficient. BB is large acceptance! Scintillator counter under BB shower can be used for this? Just use BB CAL.  Need to set proper thresholds.</FONT> -->
+
What is the thickness of the foils in the solid targets? Can't do rate estimate without those numbers.  
−
<!-- <FONT Color="Red">Want to extrapolate beam size to target, and verify BPMs agree with the HARPs (surveyed to Hall Coords).  BPMs referenced to the HARPS. Is what the BPMs reading (i.e., 0,0 is actually 0,0 relative to the HARPs.).  Is this an Ops thing? Want to know where the beam is relative to the Hall Coords (bull's eye scan below).  Beam position/angle important for vertex reconstruction.  E.g., LHRS, etc beam pos => significant corrections on optics, maybe not so much on BB (large acceptance). BPMs give some EPICS value (avg position) and that's calibrated against the HARPs for the true beam position. Measure BPMs using FADC, use that for center position => this gives another calibration? Tell MCC we want BPMs to be, e.g., 2,1 or 1,1.  Do we need analysis on this immediately (I think so); how long does that take? Note: MCC has a procedure to calibrate the BPMs for their own setup -- maybe not physics wise, but this gets us to the dump properly.  From here, we see where the target is relative to the beam, and adjust the target vertically. Steps: MCC does HARP scans.  Then ''we'' compare against BPM positions. We have a run going at the same time so we have the BPM positions at the same time.  The projected position to the target gives us an angle and offset. How does MCC monitor that they're centered on the DP apertures? Ion chambers, looking at displacements, the dump viewer.  </FONT> -->
+
−
<!-- Target Positioning -->
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<!-- <ol> -->
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<!-- <li> Need operational restrictions to be established (by Target Group).  People that can modify operational restrictions are Doug and Bob.  Need from target group: what's on target ladder + nominal current and raster restrictions.  This goes to Bob and he can update it.  -->
+
−
<!-- <li> Entrance of target 12 mm, 1 mm in each direction (2x2 raster) is sufficient.  -->
+
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<!-- <li> Center on the Carbon hole; Target team has displacements relative to the Carbon Hole => defines how to locate/place LD2.  If things are off vertically (say, a few mm), do we wake up target expert and change the encoder step. Yes. -->
+
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<!-- <li> Are the Hall A EPICS displays of the target ladder positions updated? (Hall A Status seen by MCC and Target GUI that the TO uses). Silviu: The GUI is up and running, can update the list. -->
+
−
<!-- </ol> -->
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<!-- === Ion Chamber Calibration [1 hr] === -->
+
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<!-- * Target: LD2 ('''no radiator''') -->
+
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<!-- * Target: LD2 w/ radiator (largest amount of material). <FONT Color="Red">Check with MCC. Are we risking damaging ''thinner'' targets? Hall C: one for solid targets, then one for LH2, LD2 separately.  Negotiation with MCC.  Radiator is not being used until PionKLL & using LHRS, HCAL efficiency calibration (end of run).  Perhaps we do IC calibration for LD2 (no radiator). Perhaps not big difference for solid (Carbon) targets.  Administrative restriction on max current for solid target.</FONT> -->
+
−
<!-- Once the beam is centered on the target, we then calibrate the ion chamber located just downstream of the target scattering chamber.  This device is critical for monitoring beam alignment and protecting the target.  We follow the [http://opsdocs.acc.jlab.org/ops_docs/online_document_files/MCC_online_files/Hall_A_ion_chamber_calibration_proc.pdf Ops procedure] to complete this task. This determines the ion chamber trip set points for various beam currents, energies, and target.  If there is a significant change in any one of these variables, this calibration has to be repeated. -->
+
−
 
+
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=== Raster Calibration and Beam Centering[1 hr] ===
+
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<FONT Color="Green">'''NOTE''': This happens for every new beam energy!</FONT>
+
 
<ol>
 
<ol>
−
<li> Establish stable 1 uA beam on centered on the Carbon 2mm hole target. Center of Carbon 2mm hole target is X=-0.8mm and Y=0.3mm.
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<li>Turn on All Major Detectors
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<li> Ask MCC for nominal 2x2mm raster (MCC units).
+
−
<li> Run <code>spot_pp</code> to analyze the data. Estimate the size of the raster relative to the hole in the raster pattern plot. Tell MCC how much to increase the raster current to make the diameter of the hole approximately twice the size of the box in the raster plot. Check the new size to verify your estimation.
+
  
−
</ol>
+
<li>Trigger rate scaler check. Take a run at 10,20,30 uA. What configuration in CODA? What prescales? We expect 3-10 Hz/uA (on carbon?). Is this what we see?
  
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===Initial BPM/Bulls-Eye checks===
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<li>SBS timing and amplitude check. Jiwan will do this.
  
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A bulls-eye scan is moving the beam to 4 corners of a square (2 mm in x and y) to calibrate the response of the BPMs in the DAQ using the positions given by the HARPs.
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<li>Turn SBS on and go through procedure to establish corrector currents.
  
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<FONT Color="Green">How to perform a bulls eye scan</FONT>:
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<li>Perform GEM High Voltage and Commissioning Plan. The full commissioning procedure can be found [https://sbs.jlab.org/cgi-bin/DocDB/private/ShowDocument?docid=317 here]. People: Andrew, Holly, Ezekiel, Sean, Anu, John
−
 
+
<li> GRINCH commissioning call Carlos
−
1.  You need unrastered beam:
+
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    - <FONT Color="red">caution you should not do this with a target requiring rastered beam</FONT>
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    - use carbon, optics (single-foil), or in the worst case empty target.
+
−
 
+
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2.  Ask MCC to steer the beam to the nominal center of the target.
+
−
 
+
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3.  <FONT Color="Red">NOTE: We do this above!</FONT>. Wait until beam is stable and have MCC perform a harp scan for the two superharps near the target (1H04A and 1H04B) and take a CODA run for both the left and right spectrometers during the same time. Start the coda run first before asking MCC.  Request MCC to make an ELOG entry with the Harp results, you should see all three harp wires.  Record ELOG entry numbers.
+
−
 
+
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4.  Ask MCC then to steer the beam to positions around the nominal center:
+
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    - cover at least the area the raster will cover: (1,1), (1,-1), (-1,-1), (-1,1), and repeat (0,0)
+
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    - repeat harp and CODA runs for each position
+
−
 
+
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5.  Record Harp scan run numbers and corresponding CODA run number for each beam position.  As an example, see HALOG # [https://logbooks.jlab.org/entry/3324009 3324009].
+
−
 
+
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6.  Make a record of the harp scans and CODA runs in the HAlog.
+
−
 
+
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<!-- <FONT Color="Green">How to analyze the bulls eye scan</FONT>: -->
+
−
<!-- - detailed instructions can be found at the [http://hallaweb.jlab.org/root/doc/bpm.html Analyzing BPMs] website. -->
+
−
<!--  - <FONT Color="red">the shift crew is not expected to analysis the bulls eye scan</FONT>. -->
+
−
 
+
−
== Detector Commissioning Program ==
+
−
 
+
−
<FONT Color="Green">Maybe start with the Optics since Sieve is IN</FONT>
+
−
 
+
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<FONT Color="Red">Sieve plate is IN.  Don't need it OUT to get GEMs properly working. </FONT>.
+
−
 
+
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'''<FONT Color="Red">UNDER DEVELOPMENT</FONT>'''
+
−
 
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AJRP: What is the thickness of the foils in the solid targets? Can't do rate estimate without those numbers.
+
−
 
+
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=== Turn on All Major Detectors ===
+
−
 
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Experts for each system turn on their systems for operation. 
+
−
 
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=== Trigger Rate Scaler Checkout ===
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AJRP: If you want expected rates you need to tell me what the target foil thickness is. I can generate expected rates per unit integrated luminosity.
+
−
 
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Personnel
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<ol>
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<li> HCAL: Expert driven: Scott Barus, Sebastian Seeds
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−
<li> BB CAL: Arun Tadepalli, Provakar Datta
+
−
<li> Experts to draft plan
+
−
</ol>
+
−
 
+
−
After centering the beam on the target and downstream DP apertures and beam dump, we examine whether the trigger rates seen on the BigBite calorimeter and HCAL make sense for various trigger setups.
+
−
 
+
−
Asking whether the trigger rates "make sense" at this stage is putting the cart before the horse. You cannot determine whether the trigger rates "make sense" until you have calibrated the signals in the calorimeters to energy deposits and compared them to "minimum bias" simulations with all possible physics backgrounds at the given thresholds. Realistic single-arm trigger rates were estimated for the original proposal kinematics here:
+
−
 
+
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* '''Provakar's report on GMN trigger rates for original proposal kinematics [https://puckett.physics.uconn.edu/wp-content/uploads/sites/1958/2020/07/trig_rate_gmn.pdf PDF]'''. Here the thresholds are given in units of energy deposit. '''Note that all of the trigger rates presented in this document assume 30 micro-amps beam current on a 15-cm LD2 target.
+
−
 
+
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The only meaningful thing you can do at this stage is look at the trigger rate vs threshold '''''in mV''''' at some beam current on some target, from scalers. Once you know the rate vs threshold curve for a particular target, you can scale the threshold based on changes in target and/or beam current at the same kinematics to achieve a desired rate.
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Some very rough and preliminary trigger rate estimates for SBS-1 kinematics from beam-on-target simulations with the 15-cm LD2 target were summarized in the following log entry:  
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'''[https://logbooks.jlab.org/entry/3918381 Andrew's log entry] with preliminary BBCAL and HCAL rates for the LD2 target in SBS-1 kinematics'''
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<FONT Color="Red"> Start with Carbon target, 1 uA beam.  Roughly 1 kHz (QE, singe arm) expected for BB with ''high'' trigger threshold.</FONT> 
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<ol>
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<li> Do we do a threshold scan first? YES
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<li> Do we have a simulation for the present setup? BW: estimate for QE set up (threshold < 50% of QE peak, not sure of what the rate would be).  R ~ e^{-9*thr/E_max}...  '''AJRP: We do have a simulation but to use it to estimate single-arm trigger rates realistically is very involved (see Provakar's report above) and not simple'''
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<li> Look at xscaler GUI: quick feel for what the thresholds need to be; quickest way to do this kind of a measurement. 
+
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<li> Need to pick suitable threshold to use for detector commissioning (i.e., gives a manageable rate for the DAQ).  Then calibrate threshold to energy (need to know the energy).  '''AJRP comment: Choosing a precisely optimized threshold for early stage commissioning is not essential. Needs to be high enough to give manageable DAQ rate and low enough to give reasonable efficiency for quasi-elastic scattering.'''
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<li> Choose a few thresholds and see if it makes sense. Vague, meaningless. '''AJRP: ''After'' we calibrate the calorimeters we can map trigger thresholds in mV to energy deposits in MeV or GeV, then they could be compared to simulations'''
+
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<li> Do this for both BB & HCAL.  <FONT Color="Red">HCAL is not in xscaler yet (clusters); the trigger is, however.</FONT>. 
+
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<li> Estimated rates for HCAL (as function of threshold).
+
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<li> Timing analysis between BB and HCAL.  Is this software available? Cut on HCAL 10 ns wide => identify real QE events in BB. '''AJRP:''' What we CAN do quickly is use g4sbs to calculate electron and nucleon TOF for elastic and QE events, to be ready for time correlation analysis between BB and HCAL and to calibrate nucleon TOF/beta reconstruction. But one needs to calibrate all the offsets/walk corrections/propagation delays/etc in the precise timing detectors, particularly the hodoscope. Looking for the real coincidence peak in the HCAL vs. BBCAL trigger times can be done pretty early on.
+
 
</ol>
 
</ol>
  
−
{| class="wikitable"
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=== Optics Program ===  
−
|-
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! Target !! Beam Current (μA) !! BBCAL threshold (GeV) !! BBCAL rate (kHz) !! HCAL threshold (MeV) !! HCAL rate (kHz)  !! Coincidence rate (Hz, assuming 50-ns window) '''ACCIDENTALS ONLY'''
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−
|-
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| LD2 || 1  || 0.7 GeV (= 230 mV) || 1.8 kHz || 40 MeV (= ? mV) || 91 kHz || 8 Hz
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|-
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| Single C foil || --  || -- || -- || -- || -- || --
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|-
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| LH2 || --  || -- || -- || -- || -- || --
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|}
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For a given configuration, the steps are:
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# Call MCC to stop the beam
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# The TO moves the desired target into position (that is, along the central trajectory where the beam will be)
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# Set the DAQ to the correct configuration and set the prescales accordingly to select the appropriate trigger
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# Start a new run
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# Call MCC to deliver beam at the desired current and raster size (2x2 mm^2)
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# After X minutes, stop the run and check the beam setup using spot++.  Work with MCC to optimize beam delivery on target.
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# Take data for X minutes and examine the trigger rates on the xscaler GUI (directions to bring up the GUI are [https://sbs.jlab.org/wiki/index.php/HOW_TOs#Bringing_Up_Scaler_GUI here])
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# Perform offline/nearline analysis (if necessary)
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# Post a HALOG entry of the results
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=== GEM High Voltage Efficiency Scans ===
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People: Andrew, Holly, Ezekiel, Sean, Anu, John
+
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This procedure should only be done by a GEM expert from the names listed above. Recommended but not required before optics runs. The full commissioning procedure can be found [https://sbs.jlab.org/cgi-bin/DocDB/private/ShowDocument?docid=317 here]
+
−
 
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=== Electron Arm (BB) Optics Calibration ===  
+
  
 +
====Electron Arm (BB)====
 
Andrew Puckett and Holly Szumila-Vance are the contact people for BigBite optics calibrations
 
Andrew Puckett and Holly Szumila-Vance are the contact people for BigBite optics calibrations
  
Line 195: Line 75:
 
** Time required probably ~1 h or less. Need ~few-hundred straight-through tracks per sieve hole.
 
** Time required probably ~1 h or less. Need ~few-hundred straight-through tracks per sieve hole.
  
−
* '''Optics data with sieve slit plus optics targets (and some LH2 data with sieve slit IN)''': ''Purpose'': calibrate BigBite angle and vertex reconstruction (and also momentum).
+
* '''Optics data with sieve slit plus optics targets (and optional/some H2 data with sieve slit IN)''': ''Purpose'': calibrate BigBite angle and vertex reconstruction (and also momentum).
 
** BigBite magnet is ON, energized at full current of ~710 A with polarity set for up-bending electrons
 
** BigBite magnet is ON, energized at full current of ~710 A with polarity set for up-bending electrons
 
** SBS magnet is ON, at reduced current (~30% of max at commissioning kinematics)
 
** SBS magnet is ON, at reduced current (~30% of max at commissioning kinematics)
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** Prefer '''unrastered''' beam on solid-foil optics targets. Always rastered beam on cryo-targets
 
** Prefer '''unrastered''' beam on solid-foil optics targets. Always rastered beam on cryo-targets
 
** Targets are:  
 
** Targets are:  
−
*** Optics (9 foils at z = 0, +/-7.5 cm, +/-15cm, +/-22.5cm, +30 cm)  
+
*** Optics (8 foils at z = 0, +/-7.5 cm, +/-15cm, +/-22.5cm, +30 cm)  
−
*** LH2 15 cm (without radiator)
+
*** H2 15 cm (without radiator)
 
** Trigger is BigBite calorimeter
 
** Trigger is BigBite calorimeter
 
** Need ~few hours data on each optics target plus LH2 target with sieve in. Possibly with lower threshold in BB or higher beam current, depending on rate. Need to collect ~500-1,000 events per sieve hole per target foil for each optics target position. Additional LH2 elastic data with sieve slit may also help with momentum calibration.
 
** Need ~few hours data on each optics target plus LH2 target with sieve in. Possibly with lower threshold in BB or higher beam current, depending on rate. Need to collect ~500-1,000 events per sieve hole per target foil for each optics target position. Additional LH2 elastic data with sieve slit may also help with momentum calibration.
 
** Starting optics model is from g4sbs simulation. Need to know actual magnet current to determine appropriate scale factor for simulation magnetic field to generate starting optics model. Approximate starting optics model helps to more easily identify which tracks come through which sieve holes from which foils. Unclear, but we might end up having to turn off SBS GEMs during BB multi-foil running depending on the good electron rate.  
 
** Starting optics model is from g4sbs simulation. Need to know actual magnet current to determine appropriate scale factor for simulation magnetic field to generate starting optics model. Approximate starting optics model helps to more easily identify which tracks come through which sieve holes from which foils. Unclear, but we might end up having to turn off SBS GEMs during BB multi-foil running depending on the good electron rate.  
−
* '''LH2 elastic data without sieve slit''': ''Purpose'': Calibrate BigBite momentum reconstruction and BBCAL and HCAL energy reconstruction. Also calibrate BigBite and HCAL trigger threshold from mV to energy deposit
+
* '''H2 elastic data without sieve slit''': ''Purpose'': Calibrate BigBite momentum reconstruction and BBCAL and HCAL energy reconstruction. Also calibrate BigBite and HCAL trigger threshold from mV to energy deposit
 
** With BB magnet ON at full current
 
** With BB magnet ON at full current
 
** Sieve slit is OUT (require controlled access and trained/authorized personnel to insert/remove sieve slit)
 
** Sieve slit is OUT (require controlled access and trained/authorized personnel to insert/remove sieve slit)
 
** Rastered beam at nominal
 
** Rastered beam at nominal
−
** Target is LH2 15 cm without radiator
+
** Target is H2 15 cm without radiator
 
** beam time/data requirements for this phase are driven by calorimeter calibration needs, not optics/momentum calibrations
 
** beam time/data requirements for this phase are driven by calorimeter calibration needs, not optics/momentum calibrations
 
** Use angle-momentum correlation for elastic scattering to calibrate momentum reconstruction matrix elements, assuming angle reconstruction already calibrated. We need to know beam energy for this. '''Do we need a dedicated Arc and/or eP beam energy measurement?'''
 
** Use angle-momentum correlation for elastic scattering to calibrate momentum reconstruction matrix elements, assuming angle reconstruction already calibrated. We need to know beam energy for this. '''Do we need a dedicated Arc and/or eP beam energy measurement?'''
  
−
=== HCAL Calibration ===
+
====HCAL Calibration====
  
 
With the BB calorimeter calibrated (which gives us the electron momentum), we now can calibrate the response of the HCAL detector to determine the proton momentum, where we use the LH2 target.  
 
With the BB calorimeter calibrated (which gives us the electron momentum), we now can calibrate the response of the HCAL detector to determine the proton momentum, where we use the LH2 target.  
Line 234: Line 114:
 
=== BB GRINCH Commissioning ===
 
=== BB GRINCH Commissioning ===
  
−
=== BB Hodoscope Commissioning ===
+
=== BB/SBS GEM Commissioning (Continuation) ===
−
 
+
Having completed the HV scans in BB, the following tasks are still needed for completion of the GEM commissioning, but they have different priorities and different configurations in which they can be done:
−
 
+
# SBS Latency (completed!!)
−
=== Next Steps ===
+
## Priority: Next available opportunity, could be done during normal optics and hydrogen elastic running (parasitic)
−
 
+
## Target: carbon optics of H(e,e'p)
−
<ol>
+
## Who: GEM expert presence to change the latency between runs. Shift crew to start/stop DAQ.
−
<li> If we finish early, move to LD2/LH2 target. Look at proton/neutron separation. Slowly ramp to production/reasonably high current: Verify that the DAQ can handle the rates; verify the reconstruction works at higher occupancies.  
+
## Plan: starting with a latency of 102 (see [https://logbooks.jlab.org/entry/4057468]), we will take a few runs to determine which close-by value times us in. See [https://docs.google.com/spreadsheets/d/1v4JyDDqjxQeohlNITp7jCJcX5g6YP7t5IHe3aQXcAyQ/edit#gid=0]
−
<li> BCM calibration: ABA measurements (beam on/beam off) <FONT Color="Red">Do we need the precision current source calibration ''now''</FONT>.
+
## Magnets: on. SBS at 30%.
−
<li> NOTE: Repeat commissioning steps at next beam energies.  
+
# INFN LV Scan and DAQ Stability
−
<li> Do we (can we) move up the energy/pass change if we finish early?  Will affect other halls?
+
##Requires access to send BBCal and HCal trigger to SBS standalone DAQ components. This will be coordinated opportunistically with Alex
−
<li> Note: Production data is elastic => refine calibration
+
##Priority: Next available opportunity, can be done with SBS standalone DAQ and not interfere with main DAQ.
−
</ol>
+
##Target: Any
 +
##Plan: Adjust voltage supplied to INFN GEM layers around 5.0V both below and above to find a stable LV setting with beam on the GEM detector. Run the DAQ for some time to find if the DAQ runs into errors for INFN fibers or if they can be run in stable manner. This will need to be driven by Zeke or Holly.
 +
# BB and SBS luminosity scan
 +
## Priority: To be done when accelerator can provide the maximum beam current
 +
## Target: carbon multi-foil
 +
## Who: Call Simona first to ensure carbon multi-foil is set (position and raster). GEM expert presence to monitor divider currents and adjust BB layer 0 as needed. Shift crew to start/stop DAQ.
 +
## Plan: See [https://sbs.jlab.org/DocDB/0003/000324/003/GEn%20GEM%20Luminosity%20Studies.pdf]
 +
## Magnets: on
 +
# SBS HV scan
 +
## Priority: low/as available, not to take away from GEn running and must be done after latency is timed in
 +
## Target: any
 +
## Who: GEM experts to modify HV during fixed run conditions
 +
## Plan: low current (1 uA), see [https://docs.google.com/spreadsheets/d/1ONOpMdQAgFz6FKP5G605jyuHiWJ1Sv1HHhwWhHg7GnI/edit#gid=1551623608]
 +
## Magnets: on
 +
# Check current draw on BB layer 0
 +
## Priority: To be done when accelerator can provide higher beam current
 +
## Target: 3He
 +
## Who: GEM expert to control and monitor BB layer 0 current draw
 +
## Plan: Take 1M events at high current (45 uA?) with no correction to the BB layer 0 voltage. Then correct the BB layer 0 voltage and continue running. See spreadsheet for correction: [https://docs.google.com/spreadsheets/d/1g9lXnDq6ziednc6FYCC_ml9khsA6TnveGQpzmUKBLHU/edit#gid=0]
 +
## Magnets: on
  
 
==Initial checklist==
 
==Initial checklist==
−
The following subsystems require updates prior to beam in the Hall on Sept 9.
 
−
 
−
===Hall hardware required to be ready before taking beam===
 
−
#Hall A installation: Jessie Butler, Jack Segal
 
−
#*Things that require attention or are being finished up
 
−
#*Proposed lockup time
 
−
#*General instructions to collaboration
 
−
#HCAL:  Scott Barcus, Brian Quinn, Sebastian Seeds
 
−
#*Cabling and PMT performance verified. All connections complete.
 
−
#Shower, Pre-shower: Arun Tadepalli, Provakar Datta
 
−
#INFN GEMs: Holly Suzmila-Vance, Ezekiel Wertz, Evaristo Cisbani
 
−
#Beam line: David Flay
 
−
#Target: Dave Meekins
 
−
#Gas system for GEM and GRINCH: Jack Segal
 
−
#GRINCH: Todd Averett, Bradley Yale
 
−
#Trigger: Mark Jones, Scott Barcus
 
  
 
===Software and DAQ===
 
===Software and DAQ===
Line 269: Line 152:
 
#*Analyzer
 
#*Analyzer
 
#*Event displays
 
#*Event displays
−
#*Real time display
+
#*Does 50k replay work and do we need any plots added
−
#Computers and Counting House readiness: Ole Hansen, Alex Camsonne
+
 
#DAQ: Alexandre Camsonne, Mark Jones, Bob Michaels, Ben Raydo, B. Moffit
 
#DAQ: Alexandre Camsonne, Mark Jones, Bob Michaels, Ben Raydo, B. Moffit
 
#Alarms
 
#Alarms
 
#Control GUIs
 
#Control GUIs
  
−
===Hardware required but not immediately===
 
−
#Hadron polarimeter: Brad Sawatzky, Kondo, David Hamilton
 
−
#UVA GEMs: Nilanga Liyanage, Kondo Gnavo, Xinzhan Bai, Sean , Anu
 
−
#Moller polarimeter: Simona
 
−
#HRSL magnet: Jessie, Jack
 
−
#HRSL detector/DAQ: Bob Michaels
 
  
 
===Training and safety===
 
===Training and safety===
 
#Hall A walkthrough SAF110
 
#Hall A walkthrough SAF110
 
#Read and signed COO, RSAD, ESAD
 
#Read and signed COO, RSAD, ESAD
−
#Target training: Jian-Ping Chen, Silviu Covrig
+
#Target training: Arun, Gordon, Bill
−
#Safety: B. Quinn, Jessie, Jack
+

Latest revision as of 10:20, 9 November 2022

<<SBS Main

GMn Contact Information
Hall A Phone Book
SBS Shifters Wiki Info
Documentation
HOW TOs for shift crew
Expert Tools

Four days scheduled for commissioning program

Establishing Beam for the first time

Beam centering and raster calibration [8 hours]

This program is run by Simona M. Basic outline is below

  1. BB, SBS, and corrector magnets are OFF. Target in empty position.
  2. Accelerator will establish beam straight to the dump and use this straight trajectory to find BPM offsets. Accelerator will ramp up the SBS and corrector magnets.
  3. Harp scans now done to measure beam intrinsic spot size >320um in x and y ([1] ).
  4. Call Sean to let him know you are ready for GEMs so that foil z positions can be resolved.
  5. BB is now ramped up (see the procedure) and Preshower, Shower (collectively BB CAL), and Hodoscope HV is ON.
  6. Carbon target foil with 1mm hole inserted and imaged. Position of beam verified and raster size calibrated.
  7. Ion chambers now calibrated with foils
  8. BPMs and BCMs calibrated.

BB and SBS Commissioning

At this point we have good beam and characterized beam monitors and are ready to commission our experiment.

  • This segment begins using Carbon foils and BB On (700A) with SBS OFF. Raster will be on.
  • Call system experts: BigBite (Provakar), HCal (Jiwan), GEMs (Andrew, Holly, Zeke)

There are two parts to this plan:

  1. Commissioning detectors, optimizing DAQ+replay, setting thresholds and HV, timing the coincidence trigger
  2. Taking optics data. This will require transitioning to the glass cells.

Detector Commissioning Program

What is the thickness of the foils in the solid targets? Can't do rate estimate without those numbers.

  1. Turn on All Major Detectors
  2. Trigger rate scaler check. Take a run at 10,20,30 uA. What configuration in CODA? What prescales? We expect 3-10 Hz/uA (on carbon?). Is this what we see?
  3. SBS timing and amplitude check. Jiwan will do this.
  4. Turn SBS on and go through procedure to establish corrector currents.
  5. Perform GEM High Voltage and Commissioning Plan. The full commissioning procedure can be found here. People: Andrew, Holly, Ezekiel, Sean, Anu, John
  6. GRINCH commissioning call Carlos

Optics Program

Electron Arm (BB)

Andrew Puckett and Holly Szumila-Vance are the contact people for BigBite optics calibrations

The commissioning plan (not necessarily in the following order):

  • Low current, zero-field runs: Purpose: align GEMs relative to BigBite Magnet and target center using straight-through tracks from with sieve slit and single-foil "point" target. Initial alignment comes from survey. Internal GEM relative alignment for tracking purposes is done separately using Andrew's script. The GEM HV scan/efficiency plateau should either already be done or can be done concurrently as part of this program.
    • BigBite and SBS Magnets are OFF.
    • Target = single-foil carbon.
    • Beam current = 1 uA or as low as we can go such that the BCMs still work. Note that GEMs can tolerate much higher charged particle flux than wire chambers and should tolerate magnet off conditions better than MWDCs as soft photon flux is unaffected by magnetic field
    • Beam is unrastered ("point" source of straight tracks for precise alignment)
    • Sieve slit is IN.
    • Trigger = BigBite calorimeter, threshold set for quasi-elastic from carbon, rate <~ 5 kHz
    • Time required probably ~1 h or less. Need ~few-hundred straight-through tracks per sieve hole.
  • Optics data with sieve slit plus optics targets (and optional/some H2 data with sieve slit IN): Purpose: calibrate BigBite angle and vertex reconstruction (and also momentum).
    • BigBite magnet is ON, energized at full current of ~710 A with polarity set for up-bending electrons
    • SBS magnet is ON, at reduced current (~30% of max at commissioning kinematics)
    • Sieve slit is IN
    • Prefer unrastered beam on solid-foil optics targets. Always rastered beam on cryo-targets
    • Targets are:
      • Optics (8 foils at z = 0, +/-7.5 cm, +/-15cm, +/-22.5cm, +30 cm)
      • H2 15 cm (without radiator)
    • Trigger is BigBite calorimeter
    • Need ~few hours data on each optics target plus LH2 target with sieve in. Possibly with lower threshold in BB or higher beam current, depending on rate. Need to collect ~500-1,000 events per sieve hole per target foil for each optics target position. Additional LH2 elastic data with sieve slit may also help with momentum calibration.
    • Starting optics model is from g4sbs simulation. Need to know actual magnet current to determine appropriate scale factor for simulation magnetic field to generate starting optics model. Approximate starting optics model helps to more easily identify which tracks come through which sieve holes from which foils. Unclear, but we might end up having to turn off SBS GEMs during BB multi-foil running depending on the good electron rate.
  • H2 elastic data without sieve slit: Purpose: Calibrate BigBite momentum reconstruction and BBCAL and HCAL energy reconstruction. Also calibrate BigBite and HCAL trigger threshold from mV to energy deposit
    • With BB magnet ON at full current
    • Sieve slit is OUT (require controlled access and trained/authorized personnel to insert/remove sieve slit)
    • Rastered beam at nominal
    • Target is H2 15 cm without radiator
    • beam time/data requirements for this phase are driven by calorimeter calibration needs, not optics/momentum calibrations
    • Use angle-momentum correlation for elastic scattering to calibrate momentum reconstruction matrix elements, assuming angle reconstruction already calibrated. We need to know beam energy for this. Do we need a dedicated Arc and/or eP beam energy measurement?

HCAL Calibration

With the BB calorimeter calibrated (which gives us the electron momentum), we now can calibrate the response of the HCAL detector to determine the proton momentum, where we use the LH2 target.

  • Target: LH2
  • Beam: 5 μA, raster (2x2 mm^2) (?)
  • DAQ Configuration: Name, BB CAL/HCAL coincidence trigger
  1. Call MCC to stop the beam.
  2. The TO inserts the LH2 target.
  3. The sieve is pulled OUT (if it is in).
  4. The BB and SBS magnets are ramped to their nominal currents.
  5. Start a new run
  6. Call MCC to deliver beam.
  7. After X minutes, stop the run and check the beam setup using spot++. Work with MCC to optimize beam delivery on target.
  8. Start a new run for X minutes. Shifters monitor the data using the online software
  9. Experts perform offline/nearline analysis to produce plots to illustrate the calibration/success of the measurement.

BB GRINCH Commissioning

BB/SBS GEM Commissioning (Continuation)

Having completed the HV scans in BB, the following tasks are still needed for completion of the GEM commissioning, but they have different priorities and different configurations in which they can be done:

  1. SBS Latency (completed!!)
    1. Priority: Next available opportunity, could be done during normal optics and hydrogen elastic running (parasitic)
    2. Target: carbon optics of H(e,e'p)
    3. Who: GEM expert presence to change the latency between runs. Shift crew to start/stop DAQ.
    4. Plan: starting with a latency of 102 (see [2]), we will take a few runs to determine which close-by value times us in. See [3]
    5. Magnets: on. SBS at 30%.
  2. INFN LV Scan and DAQ Stability
    1. Requires access to send BBCal and HCal trigger to SBS standalone DAQ components. This will be coordinated opportunistically with Alex
    2. Priority: Next available opportunity, can be done with SBS standalone DAQ and not interfere with main DAQ.
    3. Target: Any
    4. Plan: Adjust voltage supplied to INFN GEM layers around 5.0V both below and above to find a stable LV setting with beam on the GEM detector. Run the DAQ for some time to find if the DAQ runs into errors for INFN fibers or if they can be run in stable manner. This will need to be driven by Zeke or Holly.
  3. BB and SBS luminosity scan
    1. Priority: To be done when accelerator can provide the maximum beam current
    2. Target: carbon multi-foil
    3. Who: Call Simona first to ensure carbon multi-foil is set (position and raster). GEM expert presence to monitor divider currents and adjust BB layer 0 as needed. Shift crew to start/stop DAQ.
    4. Plan: See [4]
    5. Magnets: on
  4. SBS HV scan
    1. Priority: low/as available, not to take away from GEn running and must be done after latency is timed in
    2. Target: any
    3. Who: GEM experts to modify HV during fixed run conditions
    4. Plan: low current (1 uA), see [5]
    5. Magnets: on
  5. Check current draw on BB layer 0
    1. Priority: To be done when accelerator can provide higher beam current
    2. Target: 3He
    3. Who: GEM expert to control and monitor BB layer 0 current draw
    4. Plan: Take 1M events at high current (45 uA?) with no correction to the BB layer 0 voltage. Then correct the BB layer 0 voltage and continue running. See spreadsheet for correction: [6]
    5. Magnets: on

Initial checklist

Software and DAQ

  1. Software: Andrew Puckett, Mark Jones
    • Analyzer
    • Event displays
    • Does 50k replay work and do we need any plots added
  2. DAQ: Alexandre Camsonne, Mark Jones, Bob Michaels, Ben Raydo, B. Moffit
  3. Alarms
  4. Control GUIs


Training and safety

  1. Hall A walkthrough SAF110
  2. Read and signed COO, RSAD, ESAD
  3. Target training: Arun, Gordon, Bill
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