Day 1 Summary Notes2024

NPS COLLABORATION MEETING - 17 JULY 2024

Back to NPS Collaboration Meeting 2024

PARTICIPANTS: Brad Sawatzky, Casey Morean, Ed Kinney, Alexandre Camsonne, Hao Huang, Jerry Nines, Carlos Munoz-Camacho, Po-Ju Lin, Mitch Kerver, Dave Meekins, Julie Roche, Rolf Ent, Charles Hyde, Josh Crafts, Steven Lassiter, Tanja Horn, Bill Li, Silviu Covrig, Bogdan Wojtsekhowski, Mark Jones, Wassim Hamdi, Allison Zec, Deb, Biswas, Ryan McLaughlin, Keagan Bell

ONLINE: Ben Raydo, Dave Gaskell, Hamlet Mkrtchyan, Vladimir Berdnikov, Mike Nycz, Hanjie Liu, Vardan Tadevosyan, Avnish Singh, Marie Boer, Peter Bosted

NPS HARDWARE UPDATE (Jerry, Steven L.)

• Transportation went smooth from Hall into ESB

• Shock sensor vertical and longitudinal

• Double wood stacking was needed

• Lessons learned

• redesign cables
• back up equipment, e.g., chillers
• specify angles and magnet prior as much as possible

• Discussion about concern about lockout for magnetic hazard (NPS magnet)

• goal is to avoid that everyone working near magnet needing to be trained and put their own lock - concern is that these trainings are not offered efficiently for Users
• Note here: magnetic hazard is different from electrical
• can it be done with a perimeter around the magnet? - rope or more permanent structure; if permanent structure needs to fit into infrastructure
• alternatively, can safety be achieved with a push button and Gauss meter? - push button precedents are accelerator shutoff and one of the SOS quads in Hall C. These are periodically verified, so this would have to be done

• Actions for next install

• new bolts, nuts etc. as these got damaged during deinstallation
• shielding improved design
• better rail blocks and alignment of rails

• Shielding

• main radiation damage from front (target line of sight); Paulo had a design for rotating the magnet to avoid this, but it wasn't used during RG1a --> check this
• side shielding may not be as crucial in the future, but it's the one that limits approach to the beam line, so need to design it better
• in general, assume that shielding will be beeded

• Large thanks from the collaboration to the technical and engineering/design teams for all the support during the RG1a experiment

• What should be documented:

• to assemble will follow Paulo's drawings, but to some extent things will need to be figured out during assembly
• drawings should be updated
• any documentation on hardware should be in Wiki in addition to logbook - watch out for log entries
• anything that can be automated to allow for operation outside 8am-5pm business hours

• More time for tests, e.g., rotation tests, etc.

• put it in the installation schedule, e.g., add 2-3 days for checks at the end of the installation period

CPS STATUS UPDATE (Steven L)

• Students could help with prototype tests - no special training needed; perhaps undergrad project?

TRIGGER REVIEW AND UPDATE (Ben Raydo)

• Cluster trigger

• Real time display of all VTP clusters: cluster center position, energy, number of hits

• NPS Trigger report

• Trigger emulator
• compare fADC with VTP data with evio file
• VTP record cluster decisions, both have waveforms; analyzer checks that each cluster over threshold has corresponding 5x5 or 7x7 fADC channels readout and verifies cluster positions for mapping and inter-crate communication
• sparsification -
• pedestal drifts

• Future changes - firmware

• More robust trigger link synchronization start up & check to eliminate failures where a crate appears to be not timed in
• Auto-pedestal adjustment mode. Test a simple pedestal measurement firmware module that would eliminate the need to compute offline pedestals for each channel - adjust dynamically the drifting

• Additional possible optimizations for NPS:

• Hall B: planning fADC single bit upset monitor
• Hall B: add things into run start, e.g., if a crate needs rebooting; here, would restart the firmware every run

TARGET UPDATE (Dave Meekins)

• To detect contamination in target - experimentally best to take elastic data

• Fan controllers - do not have parts anymore for these; new parts are not made to run in cold environments

SRO - OPPORTUNITIES IN HALL C (Brad S)

• Opportunities for NPS to be SRO detector system

• Ultimate goal is to streamline calibrations to improve data taking efficiency, e.g., be able to push the data taking to near the limit of hardware capability

• update calibrations while taking data

• Full SRO would be streaming data plus analysis, but could do partial SRO too

• Best test conditions are at small angles where rates are largest

• carbon elastic perhaps where results are known

• Require what from NPS collaboration?

• labor and/or agreement to use NPS for the SRO tests?

TARGET FLOW RATE SIMULATIONS (Silviu)

• For RG1a could use the known H/He ratio for the DIS region and then use that as a correction - there is an uncertainty on it of course

• During experiment: can tell contamination to 10% level based on High Power Heater - need some other means to reduce this uncertainty for high precision experiments

NPS REFURBISHMENT (Charles)

• Discussion of necessary refurbishments:

• Temperature sensors must be replaced (Aaron B./DSG) - or rather the keysight card with the active components

• is ESB clean enough to do this work - has been done before; if not clean enough then could also put a plastic tent

• check resistance chain on dividers (Fernando):

• currently limited in voltage to 850 V due to resistor chain - can it be re-worked to work up to 1500V?

• PMTs - first few columns

• remove some from first few columns, test, and get spares (if Mark ok with it)
• check connection to crystal for dried optical connection

• Cable management - already on Steven L. list

• Resolve issue with connectors on calorimeter side (electronics group)

• possibly have an intermediate patch panel
• replace connectors?

• Optional: Shielding to shield strips on boards to reduce noise between boards

• Optional refurbishment: Crystals

• may try to bleach is all is disassembled anyway

NEXT EXPERIMENTS

• RG1B - E12-06-114 (35 PAC days)

• same setup as RG1a with similar angles and momenta (beam energies are a little differnt)
• sensitivity to beam energy - cannot combine already collected 11.1 GeV with 10.5 GeV that one can get now, but overall have flexibility
• Scheduling request has been submitted

• RG2 - E12-14-003 and E12-14-005 (18 PAC days)

• ERR already in the 2019 one - beam scheduling request?
• prepare NPS
• design mounting of NPS on large angle side
• training students/postdocs
• Action: submit scheduling request for RG2 and changeover information (need info from Steven L)

• Overall Action: combine RG1b and RG2 into one RG

• RG3 (46 PAC days)

• ERR
• CPS detailed design and test
• polarized target with spinning NH3 cell
• NPS calorimeter and BB mounting
• BB with hadron calorimeter
• training students/postdocs
• Action: equipment design to stage where can pass ERR
• Action: think of more experiments that use this setup - Bogdan has some ideas

• RG4 (45)

• requires taking NPS apart and re-assembling in ring configuration
• Action: need beam test for HCAL proof of concept prototype test

• RG5 (137 PAC days)

• same NPS setup
• needs positron beam

• View from Hall C (Mark)

• next run RG1b+RG2 (35 days + 18 days + 30 days changeover) - initial estimate in ~4 years from now
• next either RG3 or polarize LD2
• some thinking that one might run strange FF in Hall A with SOLID

=======================

NEW PHYSICS

• TCS (Vardan)

• 2116 PWO crystals
• get handle on background rates from beam interaction and show that one can handle backgrounds in the polarized target environment - do calculations first before placing additional equipment like SBS magnet
• continue using P. Degterienko codes (tested against JLab experiments) and argue what it's fine to use instead of Pythia that is from JLab perspective untested

• DDVCS (Marie)

• need to design a setup to detect 200 MeV to 1 GeV recoil protons
• issue with dilepton detection is that it's GeV scaled compared to diphoton in NPS, which was lower energy - this impacts the magnetic field downstream
• detection of muons should be straightforward
• some concepts for proton detection could be solenoid with fancy tracking system - e.g., EIC B0, but with special tracking

• Tensor DVCS (Allison)

• coherent deuteron challenging - is there sufficient resolution to distinguish from quasifree?
• check theory and see if any advantages for quasielastic with incoherent deuteron where just add proton and neutron
• in incoherent case the observable was found to be zero
• how to handle background in coherent case
• tensor polarization with ND3 - any progress? --> have a sample, but haven't done the experiment with it yet
• plan current 100nA (coherent) vs. 10uA (incoherent), but it's a different observable - need to know what the asymmetry is and what its kinematic depend
• Action: make rate estimates with assumptions on ratio elastic to inelastic FF and based on DVCS rates

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ANALYSIS GOALS

• Luminosity (Richard)

• cannot use analysis from previous experiments because target is run in different configurations for each experiment
• KaonLT LH2 correction is ~-8%/100uA - most data in range 50uA-60uA
• NPS RG1a did initial analysis and saw no correction to neither LH2 nor LD2

• SIMC (Dave)

• feature for pi0 cross sections are being implemented
• unclear if it is more efficient to implement DVCS related information to SIMC - codes for radiative corrections and GEANT simulations exist

• DIS Cross section extraction (Bill)

• one overlap point between RG1a and F2 experiments in x-Q2 phase space
• data vs MC shows a disagreement in ytar - this may be due to the HB bend not implemented correctly; there is also an issue with the overall normalization (phi and ytar distributions do not match by area) - this has been fixed by Julie in NPS RG1a plots
• systematic uncertainties: the 0.1% due to equation of state seems underestimated; one should really add an uncertainty for purity (this was there for earlier experiments); total pt-tp-pt uncertainty including acceptance is on order 0.6-0.7% (~1%). Uncertainty due to model seems to be ~2% for 11 GeV data - it was smaller at 6 GeV data, but the difference does not seem to be understood yet
• HMS delta correction - that has been observed for all experiments and is not totally understood

• DIS Cross sections from NPS RG1a (Julie)

• See large discrepancy between data and MC for LH2 ~50%; there is also a discrepancy in LD2, but it is smaller (~5%)
• The dummy subtraction has an ~10% impact on the data/MC discrepancy
• In the dummy subtraction oberserve an over-subtraction. This seems to suggest that the dummy walls are not well aligned. To test this could in the simulation move the walls and determine the impact. Alternatively, one could wait for the survey report, but note that this report would be for a warm target while data are taken with a cold target
• To check the DIS cross section extraction procedure one kinematic was analyzed by different analyzers with different approaches and all were consistent