Pre-experiment Weekly Meetings Meetings

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Meeting Minutes


Presenter 09/12/2022, 9:30am ET
  • regarding irradiations, seems like UITF will be unlikely. Possibly may use injector @20MeV. Average polarization at SLAC was higher than has been achieved at JLab. Bonn was even higher, but lower current.
  • Silver/Tungsten calorimeter is available and worked well for g2p. Sounds like target group will need two years to set up irradiations at JLab unless they get more resources.
  • Average of 30% vector polarization or less is historically what has been seen at JLab. Someone should look back at the pol data from Slac on the UVA machines to get a more quantitative estimate. Oscar opined that running irradiations at NIST may be easier than any new effort at JLab. There was a previous attempt at JLab to use the injector and it was not very successful. The beads just turned slightly purplish, and did not polarize well. Oscar called for further detailed EGS studies to assess the importance of the energy scale for irradiations. Hall B does not seem to have enough raw ND3.
  • Has been getting advise from Dave G. on how to get simc subcode into mc_single_arm. She is having compilation issues but has forward momentum. She originally contacted Narbe about trying to revive the old UVa code, but they concluded it was not promising. Dave mentioned that the Bosted Christy model has some problems at low x for deuterium. Oscar mentioned that the old codes were on Octavian which had removable drives and is probably still at JLab. JP mentioned that mc_single_arm with Bosted was used for A1N/d2n recent runs and seemed to work well. Ellie and Allison will check the code against data.
  • We want to wait to hear Dustin's availability before deciding whether to have weekly or bi-weekly meetings. JP and Oscar lean towards bi-weekly. Doug mentioned it might make sense for b1/Azz to run in FY25,26 concurrent with Moller


Presenter 08/29/2022, 9:30am ET
Dave G:
  • long time since poltarg has been installed in hall C. SANE used the FZ chicane, but not clear where those magnets are or where the telescoping stand is now. Hall C just has two BE magnets, which are used to adjust the beam 2cm to correct for the vertical misalignment of the beam as it enters the hall. Dave discussed two options: 1) Pure longitudinal running. We would need to install 2 pairs of slow rasters (do we still have slow raster?), and make mods to the downstream bench. Overall would take 2-3 months to install and not a simple task. Option 2) For transverse running (20-70 degrees) we'd need to also install the FZ magnets and telescoping stand. This would require something like 6 months installation.
  • Both options will need accelerator support. Yves Roblin was the hall A liason for g2p installation. Jay Benesch is the Hall C liason (apel).
  • The acceptance of the new Hall A/C magnet is larger for transverse running than the g2p magnet.
  • Donal mentioned that there is atleast one other approved poltarg experiment, and the NPS/CPS experiment.
  • did back of the envelope calculation for chicane at 11 GeV running. Assuming we kept the first 0.61T BE magnet (<1 degree) we would need a 7T second magnet to get 11 degrees deflection into the poltarg field. JP pointed out that g2p's largest deflection was 11 degrees at 1.2 GeV, so at 11 GeV this is suppressed to a few degrees at most.
Elena Long:
  • pointed out that the qvector for the tensor run is 11 GeV (20-25 deg), 8.8 GeV (65 deg), 6.6 GeV (70 deg), 2.2 GeV (75 deg).
  • discussed the silver calorimeter used in hall A, which might be an advantage over the faraday cup since it has already been constructed/commissioned/used. JP asked if the Hall C BCMs will work at 50 nA, Dave will check on this. JP mentioned that it seems likely that Moller would run in FY26 although it is officially slotted for FY25. If we ran alongside Moller it would mean we have to request our ERR in about 1 year, to allow atleast 1 year from ERR to floor.
Action Items
  • We need to have followup meeting with Wim and Gerry regarding impact of not aligning B-field with the qvector.
  • Meeting times. There was no single time that everyone can make. The best option seems to be Monday 4-5pm. We tentatively agreed to skip next weeks meeting (Labor day), and try the new time Monday 4-5pm on September 12. Anyone who has objection to this new time should please contact Karl asap.

Dave Gaskell, Donal Day, Elena Long, Karl Slifer, JP Chen, Nathaly Santiesteban

Presenter 08/09/2022, 9:30am ET
  • Dustin presented the following list of items he prioritized from the Review
    • 1.) Enhancing vector polarization: what can be done to improve the overall area we have to work with by doing things like increasing the magnetic field. How high can we have the field before we run into other problems. How to optimize ND3 so it polarizes high soon. (cold irradiation, microwave power increase and/or frequency modulation, applications of lattice vibrations). Need to have cold irradiations at 1K or longer duration at 4K. (Dustin thinks this bullet point is potentially the most promising)
    • 2.) For ERR we will need to show a plot of ND3 at whatever the greatest polarization is that we can get, with what every scheme gives us the highest average for a polarization-anneal cycle.
    • 3.) We need some plots showing the subtraction of the signal before tensor enhancement and after. Actually, I have one of these published already, I forgot about it when Chris asked about it, but it is Fig 4. in, but we should have some more examples made by then.
    • 4.) ssRF alternating NMR system to work optimally with the Artificial Intelligence application.
    • 5.) Crystalizes ND3 and applied ssRF to signal crystal signal.
    • 6.) rssRF research.
  • Hall B run: There is something wrong with the new NMR system. It is reporting 64% deuteron polarization (via ratio method). Coil is outside. Also something is preventing uniform irradiations. Not clear yet if it is just raster problem.
  • tensor enhanced -->0 takes seconds via rf regardless of material. 0-->tensor takes 5 mins for butanol, somewhat longer for ND3
  • Has tried 4K irradiations twice. 20 mins each. The material behaved similarly to warm irradiation.
  • UVa has a 8T warm bore solenoid that might be used for Uitf irradiations.
  • Don Crabb got LiD to 75% @.65K and 6.5T. ND3 would likely behave similarly but this was with a He3 evaporation fridge.
  • discussing with Patrizia for advise on next steps for irradiation. Two potential paths: UITF and hall B.
  • UNH can help with item 4 above: testing single crystal ND3 formation and impact on absorption line separation during TE. UNH tried a few years ago with NH3. Product was visibly different but did not verify if a crystal had been created. Will Brooks's group has a NIM on this topic. Karl will invite to discuss. (Dustin : Chemical doping of ND3 possible with BDPa or chrom-5, but not clear if these dopants would be expelled from the crystal.)
  • needs to recalculate overhead with Dustin's latest estimate for tensor state switching in ND3 instead of the Butanol estimate.
  • Will start a shared doc for ERR prep.
  • Will dig out the old document he and Dustin prepared to request beamtime at UITF
  • We will try to find a new time for the meeting so that Doug and Chris and other JLab staff can attend. Dustin can likely only attend on Tuesday 10:30 EST (9:30 CT) or on Thursday/Friday.


Dustin Keller, Karl Slifer, JP Chen, Nathaly Santiesteban

Presenter 07/26/2022, 9:30am ET
  • The slides should be posted before noon. Small changes to the final presentations can be done, but the main skeleton of the presentation should be posted before noon today.
  • It is expected that the systematics coming from drift after spin changes will be highly suppressed since Dustin’s technique can flip the spins in the order of minutes.
  • Check with Dustin after the new version Pol. vs Dose, how will the annealing be handled? In addition, what will be the default techniques ssRF or ssRF + AFP?


Dustin Keller, Elena Long, Allison Zec, Narbe Kalantarians and Karl Slifer, JP Chen, Nathaly Santiesteban

Presenter 07/05/2022, 9:30am ET
  • Allison's simulation cross section is now matching E02-019 data very similarly to Ellie's older rates code
    • Rates still in progress, but cross-checked SHMS phase-space for b1 and it looks to match well so far
  • Could we use elastic neutron data for polarization measurement?
    • Might only work for vector polarization?
    • Ellie will continue looking into HMS phase-space to see if it can be moved to take elastic data during b1 if needed in case of line-shape inconsistency of extracting Pzz
  • Possible states:
    • Negative tensor polarized compared to positive tensor polarized would be best for physics, but likely not possible to create in beam
    • Both vector polarized, one tensor enhanced positive other tensor "unenhanced" to Pzz=0
    • Unpolarized vs polarized
    • Work on-going to explore all possible options to see if we can improve statistics beyond the unpolarized vs. polarized case that we already know will work
  • There's a new Hall C magnet that has a new bore size (Chris has more details) that we might be able to utilize for better separating the two cells if we go that route
    • Dustin looking into this
  • The three equations that Dustin's asking for a cross-check on correspond to the three important aspects that he'll be putting slides together for
    • Eq. 18 --> Differential binning
    • Eq. 30 --> Rates response
    • Eq. 38 --> Spin Temperature Consistency
    • So far, Ellie has double-checked/confirmed Eq. 18 for the equilibrium case and Eq. 30 for the rates response, but is still working on Eq. 38.

Dustin Keller, Elena Long, Allison Zec, Narbe Kalantarians, Karl Slifer, JP Chen, Nathaly Santiesteban

Presenter 06/28/2022, 10:30Am ET
Nathaly Santiesteban Summary of the discussion with the theorist Jerry Miller and Wim Cosyn.

Higher order effects b3,b4 will have a contribution in the extraction of b1 and also in the Azz measurement. Therefore, the direction of the magnetic field may reduce those contributions. Currently, there are proposed two configurations: i) longitudinal with the electron beam (as it is in the proposal) and ii) along the q-vector. Wim will estimate the impact of having one with respect to the other to have the best configuration to be used in the experiment. However, this may be limited for the chicane and the beamline at Hall C. In which case, we need to run parallel and estimate the uncertainties accordingly.

  • Nathaly: Dave Gaskell was contacted and he along with Jim Benesh will work in finding the limitations of the chicane and beam lime.
  • Nathaly: Dave Mack was contacted and he will work in an estimate of what is available in the lab and a timeline for the Faraday cup and lumi monitors.
  • Dustin: We need to understand and define the helicity states we are going to use in the experiment. Therefore, if we need 2 different cells what is the configuration we are going to use?
  • Ellie: Oscar and Ellie study the symmetry and effects of the helicity state back when the proposal was made. They concluded we needed primarily vector enhanced vs unpolarized. But, this may need to be evaluated given the effects of the higher twist b3,b4, which may imply a different orientation of the magnetic field.
  • Dustin: In terms of enhancement it will be easier to have two cells vector polarized with zero enhancement and a mix with tensor enhancement,because of the continuous electron beam.
  • Dustin: The backup in case we have some issues measuring the polarization could be to measure elastic data all the time. Ellie clarified that in Azz we could get elastic data constantly and we would need to evaluate for b1 what impact will have to the statistics to take elastic data.
  • Dustin: The lineshape analysis used in the experiment will be based in two principles: i) the amount of depleting power in the hole burning needs to be 2 ices as deep in order to get the excitement, and ii) in the region that we are hole burning the spin temperature remains the same (equilibrium). The equations to understand his work are 18-30-38 from the last version of the paper Dustin sent. The word equilibrium is confusing and the best way to explain it needs to be found.
  • Dustin: He does not access the data from the papers right now, but he will send the group a set of presentations where he went through the details of the lineshape analysis that we can use to better understand his method. Ellie recommended to look into the slides of the Hall A & C collaboration meeting, where she explain the 2 factor of the enhancement.
  • Dustin: From following the Hall B experiment, it could be possible to use shim coils to enhance or increase the homogeneity of the field and increase the Tensor polarization. This idea could be tested in the following years before the experiment. It will be good to have a slide or two with this kind of improvements to the Tensor polarization.
  • Dustin: We could work in a collaboration beyond be and Azz with tensor interest. In order to work in the polarization techniques along with the experiments that could be proposed.


  • (Ellie?) Plan if we could take elastic data (T20) constantly in b1 and Azz to verify the tensor polarization on a run-by-run basis. What impact would it have for the statistics of the experiment? And what configuration would that be?
  • Dustin will send the presentations on lineshape analysis.
  • Ellie will put together a plan to find the best helicity states to run the experiment.
  • Dustin will start working on the slides for the review, and he will share with us the slides to find the best way to explain the principles and the lineshape analysis that will be done in the experiment.
  • Allison will estimate the distance between the two cells for the experiment.

Dustin Keller, Karl Slifer, Elena Long, Allison Zec, David Ruth and Nathaly Santiesteban

Presenter 06/21/2022, 9:30Am ET

Updates from Dustin: Chris has contacted him and he has informed that he will create a committee to review our experiment and he will be the chair. In order to prepare for this review he suggested cleaning the language and being clear in the terms and descriptions of the configurations used for the experiment. We will use the figures that explain better the best figure of merit. Since Nathaly spoke with Chris the previous week getting some feedback from the questions we may encounter, she suggested a meeting to discuss those list summarized in the overleaf document.

Steve Wood contribution: We need to prepare to support how we will control better than 1% all the systematics. Things mentioned in Karl's talk are good at mitigating some of them, but possibly not all of them. or conditional removal, don't need to have all issues removed already but do need to make sure we have a plan of how we're going to address it. Want to show that amount of effort going into systematics is going to be on-par with amount of effort going into the target Likely to be overlap between PAC40 (b1) ITAC and the conditional removal committee Steve thinks that swapping the two target cells will work for addressing most, but not necessarily all, of the systematic drifts Though PAC focused on the target polarization, the review committee may bring up additional aspects as well. An example of this happened to TDIS, where an issue was brought up in the 'conditionals removing' review even though it wasn't directly a PAC condition For ERR, need a well-defined scope of what needs to be built and done to be able to do it Ft

Update from Allison: Still has a discrepancy in the cross-section she's working with, coming off by about a factor of ten Will work with Ellie & Nathaly later this week to try to figure it out

Update from Nathaly: Will talk with Dave Benisch about beamline, and other folks at Jlab (including Dave Gaskell) Tighter schedule than normal this week, will be back at UNH next week

Update from Ellie: Will work on setting up meeting with us & theorists, particularly Wim & Gerry and possibly Misak, to discuss their thoughts on target field orientation


Dustin Keller, Stephen Wood, Elena Long, Allison Zec, Narbe Kalantarians and Nathaly Santiesteban

Presenter 06/14/2022 9:30 AM ET
Allison Zec (A. Zec) Cross Section Calculation Slides
  • Allison: working on the cross section calculation. She concluded we need a different simulation framework than that provided by Jixie. Pivoted to SimC, which is not geant based.
  • She needed to provide her own xs to put in. For now, working with just Deuterium, but understands that we will eventually need to include unpolarized dilution (nitrogen, helium,....)
  • Xemc for deuterium xs: which is a C++ wrapper for the Bosted code
  • She looked at the kinematics in the b1 PAC40 proposal, although she used the P0 values for E0.
  • XS looks reasonable, but a rough factor of 10 between her results and previous results from Ellie. First step is to rerun at the correct E0, then see if order of magnitude difference remains.
Attendees: Elena Long, Allison Zec, and Narbe K., Karl Slifer
Presenter 06/07/2022, 9:30Am ET
  • Dave Mack: We will need to build a faraday cup and invent a 10^-4 level luminosity monitor; perhaps a large angle muon telescope behind a concrete wall. There will need to be geant simulations. We have to build a low power (5 kW?) faraday cup. The positron runs will need a 50 kW cup and Dave has a 10 kW cup in storage from DESY. We will need to get the general specs (80-120nA usually with 200 mA occaissionaly) to the engineers and designers. It will be installed downstream. Depending on specs it could be a defacto beam dump or might be on a little elevator to remove from the beam. This has all been done before, atleast at the 3 kW level in hall, so should not be a huge problem.
    • has been going thru the old docs. Primary concern of the conditional review is tensor polarization. Just need to show you have a technical solution for polarization. Prepare a presentation, worth mentioning low power faraday is needed since existing monitors will drift by atleas 0.1% over 8 hrs. We can mention that Dave is the contact on this effort. Not sure if we will build new or use an old DESY cup. The lumi's will be trickier and details will be needed for ERR, but not conditional review. The existing BCMs will not work to 0.1% over 8 hrs. But this conditional review "is not an ERR". For the eventual ERR, JLab will want the cost of the experiment to be well defined.
    • Next 1-2 years will be NPS followed by LAD. ERR is usually needed before getting on the schedule officially.
  • Nathaly S: One possibility is when Moller runs (in 3 years?) since they need high current and we are low current. Dave: Moller is huge endeavor and may experience delays. They will also require 100% longitudinal polarization and typical running is limited to polarized beam to 2 halls. (Not clear that this is any problem for us)
  • Dave M: suggest to contact Jay B for the status of chicane. Dave Gaskell is beamline owner. David Flay may also be involved.
    • issue of beads settling over time. Might not be a problem if we wait to settle or actively "settle them". Chris suggests disks. Lumi needed to monitor these types of changes. KS: we are also considering to address this by using shorter polarization cycles than 8 hours or two in-line target cells. Each brings unique challenges.
    • z-target resolution: y-target resolution is crappy 1-2 mm. Lorentzian with long tails. z-targ then depends on angle.
    • Dave will look at the error propagation. 2 targets will have 1% luminosity difference. He has a difficult time getting around the slow drifts. Thought about maybe monitoring a g1-type asymmetry but it is convoluted with the tensor asymm. This experiment was difficult when we proposed it, but is fairly typical for positron experiments and JLab will definitely need a faraday cup for those runs.
  • KS : we received two invitations to the Hall A/C meeting; one on the experiment status and one on target. Experiment talk should be a rapid overview with discussion of recent progress. Target talk should highlight the overall good progress in made by Dustin/UVa, and also Ellie/UNH independent lineshape modeling progress.

Dave Mack, Karl Slifer, Elena Long, Allison Zec, and Nathaly Santiesteban

Presenter 05/10/2022, 9:30Am ET
  • The PAC has asked for a wiki page where we will organize the material that probes if the conditional is fulfilled. Therefore, we opened the wiki page here: It will focus in two aspects: i) the tensor polarization that will be achieved under beam conditions is 30% and ii) how the polarization will be measured. The documents supporting the background and how the experiment will address the conditional will be posted there. Nathaly will organize the wiki page.
  • One of the questions that came up in the meeting with Chris: what is needed to optimize the polarization measurements from now to when the experiment runs? Dustin will make a slide summarizing the details of: i) List of needed equipment, ii) optimization work and ii) man power. Basically, the systems need to alternate and attenuate between hole burning and phase modulation (between absorption and dispersion).
  • There was some discussion about the new technote from Dustin about deuteron lineshape analysis. Ellie presented some questions about the population plots in the technote, especially related with the eta and phi terms. Dustin and Ellie will take this issue offline.
  • Next meeting will be on Friday May 20 at 10 am.


Dustin Keller, Karl Slifer, Elena Long, Allison Zec, Narbe Kalantarians and Nathaly Santiesteban

Presenter 05/10/2022, 9:30Am ET
  • The simulation used by Narbe was SIMC. He had an older version of the Fortran code and the input files specified the packing fraction, materal, thickness, among others. The cross section weighting was probably done with F1F209. The simulation lives in UVa and we will try to get access in the following week.
  • The email to the PAC (Bob) was send, there is no response yet.

Karl Slifer, Elena Long, Allison Zec, Narbe Kalantarians and Nathaly Santiesteban

Presenter 05/03/2022, 9:30Am ET
  • Questions were raised about the best simulation package to prepare for the experiment. Right now, Allison is working in the Geant4 package, but it does not have the Hall C spectrometers. However, it has the structure of the g2p target. It seems that implement the Hall C spectrometers is going to be difficult.
  • To start addressing the best simulation package, we will invite N. Kalantarians for our next meeting. Since he has previous experience in some studies of this kind
  • New weekly meeting will be every Thursday at 9:30 am

Karl Slifer, Elena Long, Allison Zec and Nathaly Santiesteban

Presenter 04/27/2022, 10:30Am ET
Allison Zec Geant4 Simulation Update
  • Meetings with Chris Keith on Thursday (April 28) at 10 am EST.
  • Allison has a working geometry of the simulation. At the moment, the g2p target is on place. The spectrometer in place is the HMOS and there is some access to virtual detectors. The implementation of the tensor target, along with the geometry and the full hall C spectrometers have to be done.
  • Dustin will like some feedback in the most recent paper.

Dustin Keller, Karl Slifer, Elena Long, Allison Zec and Nathaly Santiesteban