Minutes of the February 11, 2014 weekly meeting

• Calorimeter in the test lab: report by Kijun
  The work was performed by Hashir, Lee and Kiun with some help from Julie.
  • Since the last meeting, all blocks of the calo have been tested using cosmic rays. The blocks were powered one by one. All but 5 blocks/PMT/ampli were found to be operational. For the 5 "bad" ones, the HV and signal cables were interchanged with neighboring blocks (up to the cables between the distribution boards and the bases). The problems are with the pmt and/or ampli. These 5 blocks will have to be pulled out of the assembly for further investigations.
  • Preparing to work on the paddle for the cosmic paddle. The screws that stuck out in the space where the cosmics paddle will go, have been replaced.
  • This week will be spend establishing the trigger, cabling the ARS and setting up the DAQ.
• Trigger: report by Norman
  • Norman confirmed that opening the front panel in order to cool the modules did not make the module work. (i.e. setting the front panel back did not break the module)
  • Coda has been installed on the laptop Norman uses in the electronic lab. It is almost functional but for using the correct VME list that allow the full reading of the trigger header.
  • Plan for next week:
    • Implement run with block transfer
    • Investigate the source of the zeros in the ADC readout. Norman will put together a list of tests he plans before performing them.
    • Norman has some questions out to Magali (regarding some LED being red and the zeros in the read out). Hoping for answers very soon.
• LED : report by Marco
  • will be at JLab next week
  • got some feedback from Magali about the LED operation. As a result went on building a lemo to rub ban cable necessary

Present: J. Roche, C. Hyde, F. Sabatie, M. Defurme, H. Albataineh, A. Camsonne, C. Munoz Camacho.
Please send comments and corrections to Julie.

• 12 GeV experiment
  • Experiment readiness review form: to submit to Thia asap. The only info missing are the one from "Utilities requirements". These info should come from JLab as our experiment is standard. Alex Camsonne is going to gather the info asap.
  • Magali reports that CODA is working fine now in Clermont and she is able to read data in a real-life setting configuration. She will soon start working on the new version of the trigger supervisor.
  • Alex Camsonne will start putting stuff in the TED space soon before people start to squat it. Things we can move: blocks, shelves, .. Carlos proposes that the DAQ be setup there but Alex C. says he would prefer to do test on speed transfer in the HRS to study the dead-time, the DAQ would be installed in the TED when we test the calorimeter (with cosmics).
  • Al. Gavalya wants to discuss a new system for the long cables. Charles is on top of this
• DVCS2: Physics progresses
  • Maxime is in the middle of things for the Cerenkov efficiency and the dead-time correction.
  • Orsay has been working on the multi-track using the method presented by O. Hansen. Again work is in progress.
  • Geant 4 simulation (by Raphael): now good agreement between Geant4 and the old Geant3 (within statistical simulation).

Present: J. Roche, C. Hyde, C. Munoz Camacho, A. Camsonne, H. Albataineh, V. Sulkosky, M. Defurme, F. Sabatie, anyon else (sorry I did not hear you)
Please send comments and corrections to Julie.

JR joins the meeting a few minutes late.

• Charles contribution to the Hall A : to read before Friday. https://hallaweb.jlab.org/dvcslog/DVCS2/159
• Maxime's DIS results: Multitrack corrections. https://hallaweb.jlab.org/dvcslog/DVCS2/160 Event with more than two track in the VDC exhibit almost energy deposited in the pion rejector, some event with only two tracks show an "electron"peak in the pion rejector. If one supposes that the multitrack events are "pions", then the correction as implemented so far over estimates the cross-section (and the correction is kinematic dependent). Question: are all multi-tracks really pion? Why? The next step is probably to check add some cuts in the focal plane. Also some questions at the end of this discussion concerning boiling correction and beam trip: Julie will dig out her notes thought Carlos remembers that the conclusions at the time where that these were not a problem.
• Carlos: Malek timing corrections (run by run) are now implemented in the standard analyzer. Malek's elog: https://hallaweb.jlab.org/dvcslog/DVCS2/155 Carlos will document in the elog how to call the new function.
• 12 GeV preparation: Magali is having trouble with starting coda: Alex will try to look at that remotely.
• No meeting next week as some of us will be at the Hall A collaboration meeting. <\ul>

Present: R. Paremuzyan, J. Roche, C. Hyde, C. Munoz Camacho, A. Camsonne.
Please send comments and corrections to Julie.

• 12 GeV preparation
  • [joining now] From Carlos: there will be two PMT shipments back from France : one for high efficiency (16 PMTS?) and another ones for "regular" PMTS. The PMTS will be shipped in January from France.
  • Alex 's trip at Clermont: The installation of CODA has been successful. The end of run routine is crashing the system maybe half of the time ; this is more an annoyance then a big issue. Magali is now working with a "realistic" setting, she has been sending some run to Carlos: some parameters still need to be tweaked (for example, the full ARS window is not showing up).
  • From Charles commenting on shielding design. See entry: https://hallaweb.jlab.org/dvcslog/12+GeV/120 A. Gavalya is proposing two new shielding pieces. One that is stuck along the beamline at the exit of the scattering chamber and another one that is stuck along the calorimeter box on the beamline side. For the first one on the beam pipe itself: still need to decide on its height. For the second one: it might results from mis-communication, it is unclear we need it and it will probably make the motion of the dark box a bit more complicated. [JR missing some discussion here :( ] The people from Orsay will try to see the impact of these shielding with Geant 4.
  • The group have a meeting with Tanja Horn about the neutral facility in Hall C. Fill the Doodle at : http://www.doodle.com/usgvy739c6nc4d6f
• 6 GeV analysis
  • Work being done at Orsay: pion calibration a la Malek, still setting up routines for pi zero subtraction. Geant 4 trying to extract DVCS cross section from the previous experiment: still work in progress.
  • Maxime and the extraction of DIS cross-sections: (1) looking at improving the multitracks corrections. (2) Charles will ping Thia for a new parametrization of the PDF. (3)Found the source of the discrepancy between the simulation and the data (angle theta- vertical): this mismatch only exists when the collimator was in. One issue is that there is no automatic reading for the position of the collimator, Alex will double check this.(4) Deadtime corrections: two different ways to compute them that gives different results. The discrepancy could be due by the amount of beam trip during the run. Maxime is checking this.
• A. Camsonne to submit his DOE early career proposal today at 5pm. Good luck !

Present: C. Munoz Camacho, J. Roche, A. Camsonne, P. Bertin, H. Albataineh, C. Hyde

• 6 GeV analysis:
  • Wave form analysis file have been produced. Malek is rechecking the timing (that was the reason for which the data were replayed). Ntuple have been produced, one and two clusters ntuple were produced.
  • Next step: improve the energy calibration of the calorimeter: Camille is doing that. Alejandro is working on the pi0 subtraction (use the two photon event to randomize the decay to non equal pions).
• 12 GeV preparation
  • Alex was supposed to meet Robin tomorrow. Alex asked question about shielding (Note I really had trouble hearing this part...)
  • Bogdan asked if it would be ok to only used S0 instead of S0+S1. Alex cannot find a reason not to agree. Bogdan also want to change the cerenkov to a shorter one in order to accomodate the FPP. Bogdan also want to make a shower trigger (the idea is to get more pion rejection) but it is unclear if he is wants to use it. Charles asked how much modifications would be need to accomodate the long cerenkov: Alex will ask the designer. For memory last time we used (S0+S1)+ long CerenkoV as the trigger.
  • Julie has some money left on her NSF grant, and she has to commit the money before December. Charles and Carlos suggest to look at PMTs. If anyone has other ideas, the order will not go in for another month at least.

• Hall A collaboration:
  • Meeting: Orsay to give the analysis update talk (15min), Charles to give the 12 GeV (20 min), Alex to give his DDVCS presentation (20 min). Talks will be on Tuesday December 12, 11am to noon (TBC).
  • Annual report: It needs to be written. Due mid december basically at the same time than the meeting. JR add-on: S. Riordan (chair of the CC) has proposed the report be posted to arxiv.
• DVCS collaboration meeting:
  • Tanja Horn has put together an agenda for the Sunday meeting (4h total).
  • Carlos asks for new comments about the agenda. What about the phi proposal? Charles says the phi idea was actually to use the SBS to detect the two decay pion (opposite charge). The Hall C setup would not be able to do that. For the Hall C setup maybe a eta decay would work better. Carlos remind us that Tanja's goal is to add DVCS to her suite of pion experiment to get her program accepted by the PAC so there might not be a point in looking at "exotic" new channel. Charles states that we should make sure to explore the possibility to use our calorimeter in Hall C.
• DVCS analysis:
  • Carlos: additional analysis pass (see last week minutes) is over. Malek will check that the timing is ok and perform some pi0 calibration. This might take a while, maybe a month or two.
  • Simulation: the simulation is running, the simulation is producing an ntuple. Right now, the simulation is used for counting rate estimates for example comparing to the 12 GeV proposal. The next set is to reproduce the result of the first experiments (keep in mind the setup was slightly different).
  • Charles ask about the status of the file at JLab? All the files are at JLab. The new files are in mss: /mss/home/munoz/DVCS2/alex3rdprod/ The structure of the files is still a bit complicated: they are still full Ttree structure (not ntuple) with many info for each block. Here is a macro that will transform them into an easier ntuple: /work/halla/dvcs/disk4/carlos/clustering.C, you need to run the following macro first to get the good environment: source /work/halla/dvcs/disk1/carlos/64bits/setup.sh

Present: P. Bertin, A. Camsonne, M. Mazouz, C. Munoz-Camacho, J. Roche

• 6 GeV analysis:
  Alejandro is back. He re-started the replay of the runs. In the last replay, Malek had found: (i) some runs had event outside the analysis window - this was a small portion of the runs, (ii) some splits were analyzed without timing corrections, while other splits from the same run were replayed with the correction. It was unclear why this happened so the whole statistic is being replayed. The replay is going fast, should be done by the end of the week. Then Malek (and Alejandro?) will have to check the timing again. Malek has made an entry with an how-to do the corrections (see elog https://hallaweb.jlab.org/dvcslog/DVCS2/150)
• November collaboration meeting
  
  • check again the agenda and talk to Carlos if you want something changed: https://indico.in2p3.fr/conferenceDisplay.py?confId=7052
  • Malek will present not only timing correction for the calo but also the energy calibration using his pi0 method. Malek's student got a grant for a PhD, she has already started to work with him on calorimeter optimization (Kine II-low). She will most likely take part to the meeting.
  • Alexandre will invite Shalev Gilad to the meeting to represent Gmp.
  • Alexandre will give a seminar at Clermont about the 12 GeV upgrade on Friday November 16.
  • Alexandre suggest to maybe had a DDVS presentation/discussion of his DOE proposal (see https://hallaweb.jlab.org/dvcslog/12+GeV/109)
• 12 GeV preparation:
  
  • Carlos will send the PMT back shortly to JLab. Alexandre suggests to wait for him to secure the TED space. Right now the blocks are in the hall, they were not flooded as flooding was minimal in Hall A (only 5cm)
  • Thia asked if the calorimeter can be moved once assembled. Carlos says that it will not be a big time saver has a survey will be needed for each move. JR: We did not talk about this: could this be way to protect the blocs of radiation damage if Gmp wants to do some high current runs. We might not be able to stall them for ever on this.
  • Trigger: Alexandre has started to look at installing a standalone version of coda at Clermont. He seems to him that he will be able to do that during his November stay (following the collaboration meeting). Having someone in France to help would be good, maybe a student? We talk about a possible student but decide to check with his adviser first. JR: who is going to do that? Also there was some comment about Magali stating that there is no change to the trigger program but I don't know why this is important here
• Hall A collaboration meeting (December 10 &11)
  • at this time DVCS is given an hour and 3 talks: 6 GeV update, 12 GeV presentation, DDVCS presentation. We have some flexibility on the organization within that hour.
  • DDVCS proposal by Alexandre (see https://hallaweb.jlab.org/dvcslog/12+GeV/109): The pre-proposal was accepted, the full proposal is due November 29 (?). Alex will use a simulation of the GEM by Seamus Riordan, he also has a version of the VGG code for DDVCS.
  • the Hall A analysis workshop will take place on December 12, it is organized by Ole Hansen.

Edited: 09/25/12, 03:55 

 
    We went over Charles' slides for the GMp collaboration meeting, as well as those available from Al Gavalya and Bogdan. Slides for this meeting are in the Hall A wiki at :

https://hallaweb.jlab.org/wiki/index.php/GMp_collab_meeting_Sept_2012

Charles posted minutes at :

https://hallaweb.jlab.org/dvcslog/12+GeV/114

• 12GeV preparation
  • We want 15 cm loop (GMP wants 20cm). The other targets Alex listed on ELOG entry 108 are ok.
  • LHRS repair with Bogdan: both Charles and Julie were contacted by Bodgan with a request to help out in the upgrade/refurbishing of the LHRS. The work described by Bogdan is upgrade of the electronic of the VDC and repair of the Cerenkov. Both Charles and Julie said they will try to provide a student (for Julie at the earliest in summer 2013).
  • Charles plans to attend the GMP coll meet. The meeting in Monday afternoon Sept 17, 2-6 pm. Charles plans to present a run plan.
• Miscellanous:
  • 6 GeV analysis: Alejandro is still in vacation: no progress since last week.
  • Alexandre is putting together a DOE early career proposal. He is proposing to build a GEM based vertex detector to try to measure Double DVCS. See: Elog 109
  • The hall A CC met last week. The Winter Hall A meeting is scheduled for Monday December 10 and Tuesday December 11 with a software workshop on Saturday December 8. Dates need to be comfirmed.
  • Pion paper: Charles and Eric still need to talk.

• Pi0 paper
  • Charles comment on Elog Results 186 Charles studied Eric's code: the asymmetries values extracted are consistant with the definition given in the paper. It seems a factor of two was forgotten in both the extraction of the asymmetry and the fact that the luminosity decreases roughly by two when considering individual helicity. So the paper seems to be A-ok. There is still an open questions about the update that is in preparation: a factor of 2Pi is floating around in the extraction of the cross-sections (see Charles' note). To go further, Charles will make sure that Eric is using the appropriate luminosity, and will check some numbers (cross-sections versus asymmetries) numerically.
  • Eric will be out of the office (maybe back in France) for two months. Before leaving, he posted the update to the paper (actual cross section as a function of phi instead of just the parameter of the fit) to ELOG.
• 12 GeV preparation: no news from Al Gavalya. The GMP collaboration will have a meeting on Sept 24, 2-6pm (TBC), Vince is actually in hcarge of the agenda. Charles will try to be present and make a plea against the "symbiotic" running in favor of a split running, or at least try to explain what are our constraints if this running mode happens.
• Producing the ntuple: no progress there (Alejandro is in Spain). Still checking timing corrections that Malek found to be not right.
• Simulation: implemented cross-section model into it. The model is by P. Kroll based on pion data. The main advantage is that the model is fast (compared to VGG for example).
• Check out the draft agenda of the November collaboration meeting. Feel free to suggest modifications and/or additions. The Sunday Hall C should be going on: participants are A-ok with he meeting, the logistic still needs to be worked out.

• 12 GeV preparation: We discuss the schedule that Thia sent us by email last week. Basically running March-June 2014 and then September-December 2014, symbiotically with GMp. From what we know no slides or memo have been posted anywhere, Alex will keep us posted as things develop. Here are some questions we have:
  • The schedule Thia sent by email is not what she discussed with Charles and Alex. Charles and Alex will have to talk to Thia again, maybe Tuesday Aug 28. What does symbiotically means? When will GMp runs the small angle part of their program?
  • There is no update with the scattering chamber: Al Gavalya has all the info he needs to try to work this out though. In plus of new windows and large exit mouth for the scattering chamber, a new stand is being designed. One needs to check that the new stand allow us to reach the small angle. Are all infrastructure modification rising the price tag of our experiment? Keep in mind we are not asking for the modifications, they are only made to accomodate Gmp.
  • Space issue: a space in the TED was proposed by Thia. It looks like a decent space and it is smaller than what we expected. Charles remind us of the space at ODU and also the availability of Tom (a tech).
  • Julie discussed her rough plans for her new NSF proposal: P. King will get involved, she plans to be at JLab for the whole 2014 and she plans to be on leave from the university from Jan. 2014 to Summer 2015.
• Pi0 paper: Eric and Carlos believe that what was published is 2 sigma_TL' That is ((N+ - N-)/(N+ + N-)). Charles wants to cross-check this himself. Charles thinks that because N+ is produced with half of the total luminosity, but the denominator of the ratio is the full luminosity the 1/2 factor is there be default. Charles will circulate a note that explains his reasoning.
• DVCS2: Orsay is following on the oddities Malek found during his timing correction study. Malek correction will be implemented soon, clustering will follow soon. Carlos expects that the ntuple will be available within 2-3 weeks.

Edited: 08/21/12, 09:52 
 
12 GeV preparations
====================
   Alex reported on meeting with T.Keppel, written summary was given by Charles in a separate Elog entry 
(https://hallaweb.jlab.org/dvcslog/12+GeV/106). 

- Concerning schedule current target is Fall 2014, with installation during summer 2014. It is unclear the impact 
of GMp running on DVCS (so far it is not annonced as a "parasitic" running).

- Concerning space, the TED space looks interesting. To be discussed further next week when more people will be 
online.

6 GeV analysis
===============
   Malek reported on data quality and time corrections with latest production files. A few problems were known 
(broken blocks), some other need further investigation (see corresponding elog entries 
https://hallaweb.jlab.org/dvcslog/DVCS2/149 and https://hallaweb.jlab.org/dvcslog/DVCS2/150)

pi0 paper
==========
   We may need to publish an erratum to correct for the factor 2 missing in r_{TL'}. To be discussed next week.

 12 GeV preparations
=====================

- We talked about the email by Cynthia concerning space in the Hall for the preparations. We thought that the Hall has the advantage of being a very "realistic" testing space, but it becomes unavailable during the commissioning of the accelerator and the Hall. Charles will write to Cynthia asking for another place with 24/7 access.

- We discussed DVCS possibilities in Hall C in relation to the 1-day workshop (Nov 14, 2012) that will take place in Orsay. It would be nice to have some estimates of backgrounds and resolutions we could achieve with the Primex calorimeter in Hall C, with and without the sweeping magnet. Another issue is the electronics (ARS vs HallD flash ADCs).

 6 GeV analysis
================

- Waveform analysis files are finished and transferred to JLab. Stub files are under /mss/home/munoz/DVCS2/alex2ndprod/ Malek will look into time corrections and check everything looks ok.

- Rafayel has posted a report on the Geant4 implementation of the DVCS setup. Maxime will add some details on the calorimeter part that he implemented. Send comments or questions to Rafayel.

 pi0 paper 
===========

- Brief discussion on the wording of the new additions by Eric.

• Starting next week we will meet on Monday at 9:15
• Tanja Horn has approched Carlos and Charles to discuss possibilities of running DVCS in Hall C. The idea would be to put together a compelling program of exclusive (and semi-inclusive ?) reactions including pi0 production and DVCS. The idea was prompted by the recent disappointing PAC results concerning pi0 studies. The current idea is to have Tanja join us at the DVCS collaboration meeting in Orsay (Nov 12-13, 2012). Discussions are on-going.
• Carlos reports that the waveform analysis of the calo data was completed. The data are beeing transfered to JLab. Carlos expect the files will all be at JLab by next Monday. Malek will perform timing correction. After that the ntuples will be created.
• Angle calculation. Malek and Carlos found the bug in the comparison of the angle of proton elastically scattered calculated (based on beam energy and measured momentum) and measured in the LHRS. Now that the bug has been fixed, a ~ 1mr systematic error remains. Charles states that this is the type of mispointing ususally obtained with the HRS, Carlos wonders why the mismatch is systematic instead of random. Now that this issue is fixed, Carlos reminds us that the original question was the actual location of the calorimeter. Elastic data revealed a 0 to 6 mm lateral displacement of the calorimeter. The deplacement amplitude depends on kinematic and even on the day of the data taking. The HRS check was just to rule out a HRS mis-pointing. The question remains where is the calo?
• Eric just posted a new version of the pi0 results: clearer figure, new text that is hopefully clearer and that doesn't introduce new notation. Goal is to put in the archive soon. We wil discuss this during next week meeting.
• DVCS3 (12 GeV schedule) Al Gavalia and Thia had a meeting last week. Unfortunately Charles could not attend. From what we know the parallel running with GMP is stillbeing discussed.

• Discussing JLab computing survey: Carlos encourages us to fill it, he explains why he is not happy with what is offered at JLab. We talked about: transfering data, changes in available software, etc..
• Wave form analysis: almost all the runs have been analyzed. It should take about a week to transfer the runs to JLab.
• DVCS3 planning:
  • New about 12 GeV planning with Cynthia? No. Charles is having an ongoing conversation about the 12 GeV setup with the Hall A tech staff (eg A. Gavalian). At issue again, having Gmp and DVCS3 on the floor at the same time. The discussion is about the angles occupied by DVCS3 but also which scattering chamber to use, DVCS scat chamb has no window to the right where gmp would want one.
  • the blocks have been moved to the hall at 45deg on beam right. The stand and the black box+cable tray and it cables are there too. But not the rails (in some containers) and the patch panels are in the storage building. We still have stuff in the Hall A laser room. The PMTs are ready to be shipped back. Michel Crouau is ready to retire, think about last questions to ask him.
• DVCS1:pi0 update from Eric elog:https://hallaweb.jlab.org/dvcslog/Results/179 Eric received Carlos's comment but has not acted on them yet. We discussed about the need for a new publications for the kinematic versus W (constant Q2) or helicity dependent? Helicity dependent cross-sections is maybe the one with the most interest. Constant Q2 is a subset of the previously published data so it is not that new. Publishing means posting on the arxiv.

Present: A. Camsonne, C. Hyde, C. Munoz-Camacho, J. Roche, V. Sulkosky.

• Report on the recent meeting with Cynthia
  Charles and Alexandre C. met with her. Very positive meeting but her follow up is confusing. It looks like she is still trying to push the GMP to be on the floor at the same time as us. PREX is not at the front of the schedule anymore (money, beam quality, etc..) but that might change, it is not clear how that collaboration will react. It is also not very clear why she is trying to get the two experiments on the floor at the same time. It is not clear if we are going to run in one or two periods. No explicit discussion about the state of beam line instrumention at the beginning, but Moeller should be with the old warm magnet still. Did not talk when we will be taken off the floor, or what will be the efficiency scheduling, the first priority was to get on the floor.
  The GMP people are : Bogdan, Shalev, J. Arrington. The proposal is there: http://www.jlab.org/exp_prog/proposals/07/PR12-07-108.pdf It is a one arm experiment that wants to use the two HRS simultaneously, they also want high current.
• Space issue for DVCS3
  Charles vonlunteered the space at ODU and let Cynthia knows about that. For memory our dark box and and cable tray got moved out of the EFD building into Hall A: space is still a very high commodity at JLab. Carlos is basically ok but concerned about last minute mechanical issues. Charles is more concerned about DAQ support. If we work for a while at ODU, we will probably have to do an assembly at JLab before the final assembly in the hall (why?? I did not get that).
• DVCS2 analysis:
  • 5 kinematics out of 8 have been replayed: one more than last week. Malek is working on timing corrections after each report. Final ntuples by september at JLab. It takes time to do this first pass, it is not only an issue of CPU but also of man-power.
  • Simulation: Last week we discussed the large effect of the resolution is twice worst if the photon falls in betwen the block than if the photon fall within the block. This was traced back to the number of blocs considered in the clustering: if the eneryg in one block is too low then that block is not considered to find the locus of the hit. This results in a bad resolution for in between-blocks photons. The simulation threshold has been lowered from 1 GeV to 100 MeV, in that situation the resolution for in-between-blocks photons is only 30% worst than in-blocks photons. Is this a real life effect? Well maybe in DVCS1 because of the trigger on the electron. In DVCS2, that should not be an issue but in time we will have to match the clustering trigger between the simulation and the data analysis. The first pass analysis (right now being done at Lyon) is doing wave form analysis, the threshold for looking for a pulse is 20 MeV, so lower than the clustering threshold .

Some notes on today's meeting:
-----------------------------------

Online: Pierre, Malek, Julie, Sylvain, Charles (part-time), Alex, Carlos.


1.- nDVCS proposal - Malek posted some projections in ELOG
    (DVCSNeutron/107). Still not fully clear how one single beam energy
    allows the separation of DVCS^2. It seems that the acceptance in xB
    might be enough to get reasonable error bars. Also, it seems that xB
    is correlated (if so, why?) to the missing mass so that binning in mm2
    allows to extract DVCS^2(!). This needs to be investigated further.

2.- E03-106 paper - Review of comments (essentially those by Kees and
    M.Garcon). Charles will talk to Kees about the formulation of the
    abstract. We agreed also to mention the impulse approximation in the
    abstract and slightly change the wording in the text (around Eq.4).
    Charles will take care of these wording changes. Once done, we'll
    answer to M.Garcon and submit the paper next week when Eric is back.

3.- PbF2 blocks quote - Julie discussed the details of the previous order,
    as well as the details of a similar order by Mainz (see  ELOG
calorimeter/250). Mainz specified a
    radiation hardness requirement as part of their order. Not clear if
    SICCAS did test the blocks for radiation hardness before shipping
    them. Julie will try to find out and request the final quote for us
    soon (Kees needs it by mid-August).

4.- FEL tests - Julie submitted the proposal. It has been basically
    approved (there is no formal approval process for FEL). Julie
    requested the FEL sometime from 10/15 to 12/15, we don't know yet the
    exact dates that they will provide us with.

    Julie has ordered the curing lamps, the estimated delivery date is
October 3rd. She will work on a setup to hold the curing system.

    Sylvain presented further results on block transmission (details at
http://www.jlab.org/~jroche/deb or in ELOG entry calorimeter/251).
Transmission was measured at different (transverse) positions between the
target-side and pmt-side.

5.- Calorimeter design - Pierre is working on the design of the new
    calorimeter (PMT/base, LED, etc). Alex/Charles will ship him an old
    block+PMT so that he has all the details.

6.- Collaboration meeting - Oct 15-16 (after DNP) seems to be the
    preferable option. It would be good to invite external speakers on
    different topics (Charles sent an email with a few topic suggestions
    before). Choice of topics/speakers to be continued offline.


 NEXT MEETING: Tuesday Aug 14 at 10:00/16:00 - Please join!
=============================================================

Some notes on today's meeting. Carlos.

---------------
Online: Eric, Malek, Carlos

1.- nDVCS proposal.

- At this moment Malek finds similar error bars in the DVCS2 extraction
  with one or two different energies. I think something is wrong, and it's
  not what I find when I do that with my code on the proton. Malek and I
  will work offline to solve this issue.

- Usual (but shorter) discussion on kinematics: 1 or several Q2, blabla...

2.- nDVCS paper.

- Quick review of comments to the paper so far (Kees+Arrington). No major
  issues. Eric will send the paper to all authors (only sent to the Hall-A
  Collaboration so far).

- Discussion on M. Strikman's comments on FSI. Not easy to estimate what
  he asks for. We should add a sentence about it in the paper, but not
  clear which one...

- Eric and Malek are going to circulate a "new version" of the paper with
  Simonetta's model and discussion. We should later decide if we take it
  or keep the previous version.

3.- Collaboration Meeting.

- Eric will be available in October (except for 10/8), and Malek will only
  know in September. Malek also volunteers to host the meeting in Tunisia
  if people are interested!


NEXT MEETING: Tuesday 8/7 at 10:00/16:00 - You're welcome to join!
=====================================================================


Mon, 30 Jul 2007, Carlos Munoz Camacho wrote:
>
> Hello,
>
>   If enough people are available, let's meet tomorrow for a short meeting at
> 10h/16h. Possible topics:
>
> - nDVCS proposal
> - Fall Collaboration Meeting
> - Long paper update (if Franck is there)
> - etc..
>
> Carlos

Dear colleagues:

   Find below some minutes from today's meeting.

Carlos

----------------
Online: Charles, Malek, Pierre, Carlos.

- nDVCS proposal: Discussion on Malek's latest estimate of DVCS^2 with VGG
  model. Some issues raised on how could both the imaginary and real part
  of the DVCS amplitude be very small and, nevertheless, obtain a very
  large DVCS^2. This seems suspicious at this point and Malek is going to
  investigate further. Notice that at this point Malek is only including
  the 1st and 3rd terms of equation 66 in Belitsky's paper and neglecting
  the 2nd and 4th terms. To include the 2nd and 4th terms, we need the
  imaginary part of CFF Etilde which is not provided at this moment in the
  VGG code (I'll contact M. Guidal). Malek can at least include the first
  2 terms within the 2nd term (those not depending on Etilde), i.e. assume
  Etilde=0, but include _all_ terms depending on H, Htilde and E.

  General agreement on the need of two beam energies to separate the
DVCS^2 term regardless of VGG calculation (we cannot based our physics
results on the predictions of a model).

  Malek will continue working on the proposal by estimating the error bars
on the extraction of each coefficient when using two beam energies. For
the acceptance at 4.8 GeV he will, at least for the moment, use the same
simulation at 6 GeV and correct by hand the difference in the HRS momentum
bite. Other option is to use Pierre's fast simulation (B**h). Ideally (and
later), Franck would produce a Geant simulation at 4.8 GeV.

- nDVCS paper: Malek asked about showing Simonetta's prediction in the
  nDVCS paper. Pierre preferred not to. According to him, VGG model is
  shown to motivate the JuJd sensitivity whereas in Simonetta's model JuJd
  is fixed (and somehow taken from the lattice). Charles had not read
  Simonetta's paper and had not yet an opinion. I myself had no strong
  opinion either.

- Funding: Kees has a "small but non-negligible" chance of getting money
  to buy 100 PbF2 blocks beginning of August. Charles has asked Kees to
  ask Sirish for the specs of the previous order. No reply yet. Charles
  may contact Sirish directly. If JLab is buying the crystals, the request
  for a quote must be done by JLab. Charles will follow up on it.

  Side comment: Charles have asked Javier Gomez to be the physics liaison
for E07-007. No answer yet.

- pi0 analysis/paper: Pierre is still working on kin2 results. We will put
  the paper on hold for some more time.

- Some discussion on (prospective) students about timing and possible
  assignments. Also, Charles will probably send out a postdoc ad soon.


NEXT MEETING: Tuesday 7/31 at 10h/16h. Please join!
====================================================


On Mon, 23 Jul 2007, Carlos Munoz Camacho wrote:

>
> Dear colleagues:
>
>   Let's meet on Tuesday at 10h/16h for our "regular" DVCS meeting. On the
> menu:
>
> - nDVCS proposal
> - nDVCS paper
> - pi0 (analysis + paper status)
> - Funding
> - FEL tests and proposal
> - Any Other Business
>
>
> Carlos

Here are a few minutes on today's meeting. Feel free to comment, add or
correct:

Present: Alex, Pierre, Malek, Julie and Carlos

1.- nDVCS proposal. Long discussion on beam time request and physics
    goals. Options considered:

a) Only Q2=1.9 GeV2 with two beam energies:
   Pros: physics goal clear (DVCS^2 separation)
   Cons: hard to justify the 600h requested (especially the 450h at
4.8GeV)

b) Two Q2 points with 2 beam energies each:
   Pros: easily fits into a 600h request.
   Cons: hard to justify the physics of a Q2 dependence on the neutron
(that we will already have on the proton)

We discussed the pi0 cross-section measurements and whether it should be
part of the goals:
   Pros: it can add beam hours to the experiment
   Cons: hard to justify its measurement that so far seem very small on
the neutron (from our previous data).
An L/T separation seems out of reach, and without it, the physics of the
measurement much less interesting.

No real agreement reached. Absents are welcome to give their views on
this. Malek will continue to work on the proposal with a choice of his own
at this point, which can be revisited later.

2.- Discussion on the MRI review. Pierre pointed out that we should never
    justify the extension of the calorimeter based on the increased
    t-acceptance for DVCS and only mention the pi0 measurement
    improvement.

3.- FEL proposal. We decided to submit it soon, after the agreement of
    those absent. This will be a test of the procedure (with 12 blocks).
    If everything goes ok a larger proposal will need to be submitted to
    test all blocks of the new calorimeter.

   We agreed to start these tests in late October when Pierre will be at
JLab.


That's all folks!

Carlos

PS: Next meeting Tuesday 7/24 10h/16h. Plan to be there: on fera l'appel!