Meeting Summary Notes

NPS COLLABORATION MEETING - FEBRUARY 1-2, 2021

HALL C UPDATE (Steve)

• HMS status

• many detectors have been refurbished
• dipole momentum range up to 7.4 GeV/c (high-end momentum range of HMS) - may need to rope off platform at high fields

• First opportunity to run NPS Phase-1 in 2023 (E12-13-010/E12-13-007 and E12-06-114 additional DVCS days moved from Hall A)

• Estimated time to install NPS start to finish: 3-4 month assuming pre-installation tasks have been done ahead of time

• HB removal ~ 2 weeks
• Target foes not have to be removed to install the NPS (see page 4 of Paulo's talk

• Action item:

• check on plans for testing HMS hodoscope paddle in magnetic field
• detailed installation plan
• check what is needed formally to add E12-06-114 to the run plan, e.g., amendment to ERR 2019, submission of beam time request, etc.

MECHANICAL DESIGN (Paulo)

• Much progress with design and procurements

• Biggest challenge at the moment: routing cables to patch panel and accommodating movement for configuration changes

• detector slide cart weight ~3000 lbs - need to determine how to best push it for different detector locations

• Stair case: for any detector support structure that people will stand on need approval from structural engineer - e.g. QWeak platforms in past

• Action items:

• make small table with time estimates for rotating magnet, moving magnet from one side to another, etc.
• Plan any work on target platform before May 2022 (before nuclear target running)

SENSORS/HV BOARDS&CABLES/SLOW CONTROLS (Aaron)

• Much progress - 1100 HV cables were fabricated

• HV cable testing still needs to be done

• Certification of Samtec connectors

• connector rating from manufacturer seems to not match the operational condition with range up to 1100 V
• note: if change connector also need to change HV board
• path forward: test connector up to 1100 V and document the results (DSG)

• Long cables (140' GPW 42cond) will be available over time in the test lab - length selected to be what is needed in Hall C

• Action items:

• test HV cables
• test Samtec connectors and document

DAQ/ELECTRONICS (Brad S.)

• Support hardware

• Cable run - working with Paulo
• Grounding - isolate NPS chassis so that do not contaminate the system

• Reminder of trigger: generated by VTP and masked to select crystals that are part of the cluster

• Cluster trigger 3x3 with row at the seam - going to smaller cluster is possible, but involves significant work
• VTP logic - if find a valid cluster then form trigger
• full waveform for all crystals participating in the cluster (identified by the VTP) will be recorded

• DAQ hardware and firmware/SW

• FADCs are available, but need to coordinate with other projects (e.g. SBS) --> reserve FADCs for NPS
• FADC synching with RF - never been done for FADC, might be an interesting run plan item, but not needed for NPS
• Firmware development ongoing
• Need Analyzer support for event-blocking mode, decoder updates - critical path item

• examples may be available from Compton polarimeter activities

• Slow Controls

• LED board design nearly done - next need to procure and fabricate
• LED control GUI needs to be designed

• NPS Assembly area

• Detector assembly area identified and cleared in the test lab - accross from NPS crystal clean room; some coordination with design and/or Walter's groups
• DAQ in the test lab should be available later in the year

• Action items:

• Document electronics/DAQ items in the Wiki - material that could be of interest in future reviews
• Prepare an assembly plan for CH similar to what was done for mechanical mounting

FEG UPDATES (Chris Cuevas)

• Need to get started on sparsification firmware/SW

• Slow controls

• LED board - should have pulse mode available during regular run
• VME crate should be available for LED drivers

• Action items:

• Start on sparsification firmware - critical path item
• continue all other activities

ANODE CURRENT (Fernando)

• Anode current setup is now ready - next need to develop the procedure to measure anode current

• need personnel from NPS collaboration (2-4 hours/day)

• Action item:

• measure and document anode current - directly related to availability of bases - critical path item

DETECTOR FRAME (Emmanuel)

• Assembly completed in Orsay and frame was shipped to and received at JLab in January

• Detailed NPS mounting plan document was developed

• Note: the final frame for the NPS will be available for the assembly in the test lab
• Add cooling/pressure tests early on, e.g. near day 2

• note: if disassemble and then reassembly tubes have to do a leak check everytime

• May want to add explicitly to check for bubbles in optical grease
• Check of magnetic shielding to be done later - need full field

• Time frame assembly - current estimate: later in the year

• International travel likely not possible until September
• Need availability of and timeframe for components

• Note: NPS assembly moves to Hall C as one unit

• Action items:

• Add cooling/pressure tests, etc. in NPS mounting plan
• Check Kapton tape - isolation configuration

CRYSTAL STACKING (Vladimir, Hamlet, Hakob)

• Estimate to have 1164 Crytur crystals at JLab in August 2021

• some Crytur crystals may be needed for ongoing R&D projects
• there are also on order 400 SICCAS crystals - there are less radiation hard and not as uniform as Crytur crystals

• Crystal stacking strategy: 3 possible options based on October 2020 discussions)

MAGNET MAPPING (Charles)

• Measurements were done up to 250A - see differences betweem Opera calculations vs. data

• Note: measurements were done with main coil only, while Opera assumed both coils (main and corrector)
• could rerun TOSCA model to give confidence that the magnet works

• Magnet steel

• magnet steel predominantly 1010
• steel used: from BNL and additional steel from another JLab magnet
• in general, newer steel may saturate earlier than older steel, but does not seem an issue here

• Overall plan for the magnet:

• Demonstrate it works as advertised
• Fringe fields - to be tested in the hall - need accelerator test plan (HMS optics, beam displacement, etc.)

• Action items:

• Rerun Opera with just the main coil at 250A
• Accelerator test plan (Jay)

SOFTWARE DEVELOPMENT (Carlos Y., Steve)

• Working in NPS clustering algorithm - integration into Hall C Analyzer

• idea is to develop multiple different algorithms to compare

• Other items to be done:

• VTP decoder updates
• solve and implement data unblocking
• merge multi-threaded podd with hcana

• Data unblocking

• There are actual data files (Brad S.)
• Some codes are around, but nothing yet of production quality
• some examples from Compton polarimeter activities from about one year ago are available (Alexandre)

• Waveform analysis

• Orsay has some examples of code
• Data are available from SHMS

• Calibration and monitoring software

• need guidance on how calibrations are done - calibration methods

• Action items:

• Algorithm development
• Multiblock

ASSEMBLY PLAN - ITEMS NEEDED

• Installation plan

• Mechanical mounting plan

• Crystal wrapping plan

• Software test stand and counting house assembly plan

• Cabling maps

• Resources plan - on-site personnel

• Accelerator test plan

CALIBRATION PLAN

• Calorimeter calibration Methods:

• Cosmics
• Elastics
• Exclusive pi0
• LED pulses (LED peak wavelength 465 nm)

• Tests before moving to hall - in general test beforehand as much as possible to identify possible bottlenecks:

• Mu metal shield test - could use Helmholtz coil setup Hall A
• HV calibration PMT
• DAQ/electronics - LED, cluster trigger checking
• Cooling tests
• Slow controls, interlocks

• Tests after moving to hall:

• Mu metal full assembly with magnet on
• Fringe fields
• Calibrations crystal

DAQ/electronics - OR w/ VTP

WACS - NPS PHASE-2

• There are two WACS experiments: 1) unpolarized (cross section), 2) Polarized WACS (asymmetry, needs also CPS)

• Unpolarized WACS was part of the ERR 2019 - main difference to Phase-1 is the radiator

• For polarized WACS need additional crate for GEM readout

• Action items:

• prepare beam time request for unpolarized WACS
• set milestones for formal ERR request for polarized WACS