Minutes Jan2011 to June 2011

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Minutes of the weekly analysis meetings from January 2011 to June 2011

6/22/2011: Present: Kalyan, Jixie, Chao, Pengjia, Mellisa, Vincent, Ryan, Toby, Alexandre, Jie Liu

  • Toby:

1) Tested 4 cables for the slow raster with Ryan
2) Worked with Chao and Jixie to prepare to measure the target field

  • Ryan:

1) Continue working on the HRS trigger

  • Melissa:

1) Replaying xgt2 data. Looking at the pedestal of adc to find out if there are dead channels
2) Updating the safety document for g2p based on the one used in SANE experiment

  • Chao:

1) Preparing a computer in the hall for the DAQ of the 3rd arm 2) Preparing for the target field measurement

  • Kalyan:

1) Continue designing the 3rd arm
2) Got confirmed from Al that 3rd arm can not be used in GEP

  • Jixie:

1) Learning the optics from Nilanga, will meet with Vince to discuss the optics plan 2) Try to test the magnetize effect of the translation table. Replace some steel bolts and nuts with plastic ones. 3) Running simulation to get local beam dump opening for Al. But the HRS transportation routines from Min do not work.


  • Pengjia:

1) Continue working on the remote control program for the function generator

6/16/2011: Present: Kalyan, Jixie, Chao, Pengjia, Min, Mellisa, Vincent, Alexandre, Jp, Ryan, Toby, Karl, Jie Liu

  • Toby:

Learning how to replay xgt2 data in ifarml#. He has put the analyzer and readme document in the g2p work disk. Currently he is replaying for Cherencov detector.

  • Melissa:

Try to generate a HRS status table. She is also learning how to replay xgt2 data and check the detector status by data. Currently she is replaying for VDC detector. JP mentioned that talking to SRC or xgt2 people would also help.

  • Min:

1)Study and understand HRS optics.
2)Finish the HRS transportation without target field for both 5.69 degree and 12.5 degree. (not test yet.) will work to find out the resolution of these packages in the rest of this week.

  • Karl:

1)Updated the hall-a website and wiki, put g2p as the upcoming experiment.
2)Updated the run plan in the g2p wiki.
3)In charge of the readiness review response.
4)Suggested to put all technical notes into a safe location which is easy to access.

  • Ryan:

1)Finish the website for g2p. Call for comments.
2)Working on the trigger of the left arm. S1 will be replaced by S_{1}^{n}, which is 16 bars and 32 channels.
3)Working with rates using Karl's program. Will write a tech note for it.

  • Chao:

1)SC have been moved into the hall. Will set up the HV and test it next week

  • Jie Liu:

1)Just join g2p and A1n experiment.

  • Pengjia:

1) Slow raster has been moved into the hall
2) Write a remote control program for the function generator

  • Kalyan:

1)working on 3rd arm and SC of HRS

  • Jixie:

1)Learning HRS optics. Just had a optics meeting yesterday.
2)Will working on the optics plan with helps from Jin, Vince, Nilanga and John
3)Working on GEP simulation


6/1/2011: Present: Kalyan, Jixie, Chao, Pengjia, Min, Mellisa, Vincent, Alexandre, Jp, Ryan, Toby Phone: Karl

  • Pengjia:

1) Solve the uniformity problem of the slow raster (https://hallaweb.jlab.org/dvcslog/g2p/112). Check his slice here: https://hallaweb.jlab.org/dvcslog/g2p/110602_225313/Slow_raster_uniformity_test2.pdf

  • Toby|Ryan:

1) Working on the poster
2) Ryan also working on calculating the radiation of electron going through various materials in the scattering chamber. He will double check the material thickness with target group.
3) Toby will help to map the target field with Jixie

  • Melissa:

1) Playing with replay, learning to reconstruct data and try to understand HRS

  • Min:

1) Working on poster with other students (Mellisa, Chao and Pengjia)
2) Running snake to generate HRS transportation routines

  • Chao:

1) Help to prepare target field measurement

  • Jixie:

1) Prepare for target field measurement. The target coil might be cooled down tomorrow.
2) Finalize the central ray of 903A septum map: the angle is 5.69 degrees and the energy is 2.956 GeV. 

  The configuration file with this map for SNAKE is ready. We might need several maps for the snake 
  since the iron start to get saturated from about 700 A.

3) We need to find out "B vs. I" curve for the real field once the septum installed in the hall.

  • Kalyan:

1) Working on the 3rd arm. 2) We will cancel this meeting for next week due to user meeting and hall a collaboration meeting.


5/25/2011: Present: Kalyan, Jixie, Chao, Pengjia, Min, Mellisa, Vincent, Alexandre, Jp, Powel et. al (From RadCon.) Phone: Karl, Ryan, Toby

  • Karl:

1) Calculate the kinematics and rates. New file for kinematics rates and run schedule is ready (can be found in the elog too)
2) Ryan and Tobe will participant the student poster competition. Min, Pengjia and Chao will also participant. Students should discuss to avoid too much overlapping.

  • JP:

1) About the run schedule for 1.7 GeV, need to negotiate with Halls B and C
2) Karl's run schedule in the file looks good in overall, need to address some small mistake in typo. For instance, in the 1.2 GeV, G2P transverse setting (90 degrees) will run before GEP (20 degrees)
3) Got permission from HKS group that we can use either HKS power supply or HES power supply. For HES power supply, Japanese can send some extra control cards
4) Need to purchase DC power cable
5) Discuss if need to replace the S1. Kalyan said it is necessary and he would do that.

  • Radcon, Gorge:

Give a presentation of the radiation simulation for the local dump. The slice has been uploaded into the elog: https://hallaweb.jlab.org/dvcslog/g2p/114

  • Pengjia:

1) Testing the slow raster. He run a simulation to address the hole in the center. It turns out that it is due to the phase difference between AM and the Sin function. The phase of the function generator is a random number which is out of control. Will work on that for the rest of this week.

  • Min:

1) Finish calculating the acceptance weighted solid angle and its momentum dependence. The delta acceptance is from -4% to 3% and the average solid angle is 3.9 msr.
2) Learning how to reply data

  • Melissa:

1) Learning how to replay xgt2 data

  • Chao:

1) Learning Jixie's Geant4 program and will use it to study the background for the 3rd arm. 2) Will help to measure the target filed

Kalyan: 1) Some of the S1 PMT have extra pulse as getting old and old. He will replace them with 16 new bars. 2) Continue working on the 3rd arm


  • Jixie:

1) Prepare to measure the target filed:
A) Translation table ready
B) 3-axis probe ready
C) Oscilloscope ready
D) Need to find a table
E) will do the measurement when it is cool down
2) G2P optics meeting has been schedule in 6/15, 14:30~17:00 3) Check the septum field

5/19/2011: Present: Kalyan, Jixie, Chao, Pengjia, Vincent, Alexandre

  • Jixie:

1) Run simulation to find out the bending angle for septa in max current, 903A. This filed will bend 2.960 GeV electron from 5.69 to 12.5 degrees.
2) Prepare for target field measurement. The goal is to measure the field to a relative accuracy of 1%. Here are some information:

  1. plan to measure the field at 10 cm step at Z from 70 to 110 cm and 2 cm step in X from -30 to +30 cm, and 2 cm step in Y from -30 to 30 cm.
  2. For the position accuracy, 1 mm will be good for this purpose.
  3. Need a translation table which can move 60 cm distance, (trying to borrow one from magnet group).
  4. The field will be between 100 and 3000 Gauss.
  5. Wish to have a 3-axis probe.
  • PengJia:

1) Show slow raster pattern, which is from a sin wave modulated to t^0.5. There is a hole in the center for unknown reasons. He will try to address this problem.

  • Min:

1) Working on calculate the HRS acceptance weighted solid angle. She has finished scan the positive deltaP, which is defined as (P-P0)/P0. The result shows the acceptance weighted solid angle is from 3.88 t0 4.05, from zero deltaP to 4% deltaP. She need to repeat this for the negative part.

  • Chao:

1) Will help Jixie to measure the target field map 2) Finish the cross section library, which can be used to study the background of the 3rd arm.

  • kalyan:

1) 3rd arm: will not use neither the tracker and the proton tower of DVCS-I due to the fact that can not change the gain for each individual channel. Plan to use a spare S2m SC to be the E plane. Will talk to Mark Jone for a thin SC (2.5mm~10mm) to build a dE plan.

5/12/2011: Present: Kalyan, Jixie, Chao, Pengjia, Jian-ping, Vincent, Alexandre, Melissa Phone: Karl, Ryan, Toby

  • JP:

1) we re very close to finalize the kinematic configuration. Check Karl's elog entry for details: https://hallaweb.jlab.org/dvcslog/g2p/109
We will run
A)2.3 GeV in 5.010T field and 0 tilted
B)2.3 GeV in 2.505T field and 0 tilted
2) Need to recalculate the radiation in the hall after we finalize the kinematics configuration
3)Another power supply for the septum: either one from the HKS can provide as much power as the one used in BigBite. We need to
A)ask HKS group from permission to use it;
B)Check the location to place it in the hall;
C)Check the cooling power and so on.
4)Need to design cooling system for the local beam dump

  • Pengjia:

1) Finish the low current BCM test, see the report here http://www.jlab.org/~pzhu/report/BCMtest_low.pptx

  • Min:

1) Cross check the HRS acceptance if the beam is tilted, see her plots here http://www.jlab.org/~mhuang/g2p/tiltangle/
2) will Calculate the HRS weighted acceptance. The unweighted acceptance with septum is about 40 msr. http://www.jlab.org/~mhuang/g2p/tiltangle/accep_2gev_5T.png. She will provide the weighted acceptance soon
3) Working on record the HRS status

  • Melissa:

1) Working on record the HRS status

  • Kalyan:

1) Working on the third arm trigger

  • Chao:

1) Working with Kalyan on the third arm triggers 2) Finish the draft of the report of the test for septum

  • Jixie:

1) Working on simulation to provide necessary information A) Provide fitting to calculate kinematics https://hallaweb.jlab.org/dvcslog/g2p/108
https://hallaweb.jlab.org/dvcslog/g2p/110
B) Verify target cell dimension and beam pipe dimension: https://hallaweb.jlab.org/dvcslog/g2p/111

5/4/2011: Present: Kalyan, Jixie, Chao, Pengjia, Jian-ping, Vincent, Alexandre, John ReLose Phone: Karl, Ryan, Toby

  • John: Showed some slices about the acceptance with 9cm up shifted in SNAKE.

http://www.jlab.org/~lerose/ppt/g2p/accept-9cm.pptx
1) Acceptance drop to 1/3 of the origin (agree with Min's NEW result with realistic target field)
2) Vertical angle from ideal target field is different from the realistic field.
3) Q^2 reduced no more than 10% (John and Min will run for 2 GeV electrons to verify this)

  • Jixie: Finished a septum measurement with Chao. The conclusion are

1) All 3 coils go to the same direction
2) The slope of "B Vs I" is about 12 G/A, far away from the value from Tosca, 17. This might be due to the low current and the affect from the iron. In the measurement Jixie did not cycle the magnet.
3) There is about 4% difference between left and right.
4) The septum power supply can provide maximum current of 550A only, which is not enough for G2P. But we will live with this.

  • Pengjia:

1)Still working on BCM low current test with Alex
2)working on slow raster DAQ
3)working on Tungsten calorimeter calibration

  • Kalyan:

1)Got design drawing of the position tracker, need to talk to Al to find out a position for it
2)May need to bind several channels into one unit in order to reduce the total number of channels

  • Chao:

1) Working on the positron part of the event generator
2) Working with Jixie to measure the septum field

  • Min:

1) Working on SNAKE to find the acceptance after 9cm shifted
2) Learn to reply Xgt2 data

  • JP:

1) Encourage everyone to attend the G2P|GeP review in Friday
2) We will change the meeting time of next analysis meeting to Thursday(May 12), 1:30 PM, Room A110.


4/27/2011: Present: Kalyan, Jixie, Chao, Pengjia, Jian-ping, Vincent Phone: Karl, Ryan

  • Jixie:

1) We can not do straight through beam for G2P 90 degrees after 9 cm up shifted due to the fact that the opening is just 8.57 cm. The opening for 20 and 0 degrees is 20 cm. Check elog entry 99 for details and check Pengjia's elog entry 98 for more pictures.
2) Working on the septum field issue
3) Working on the plan to measure the target filed

  • JP:

1) Need to double check and optimize the run plan to avoid unnecessary installation time
2) The beam dump design need to be finalize as soon as possible
3) Septum issues, will have a meeting to discuss in Friday
4) All students are supposed to prepare some slices and give a 5~10 minutes talk in the analysis meeting

  • Pengjia:

1) Repeat the talk he gave in the HAll-A group meeting http://www.jlab.org/~pzhu/bcmtest.pdf

  • Chao:

1) Measure the proton town dimensions for G4
2) working on the proton background 3) Studying the G4 program. Jixie will put the proton tower geometry into the program and Chao will run the simulation.

  • Kalyan:

1) Got the position tracker and one DVCS proton tower. Need to discuss with Al to find out position to put them
2) Can not run the 3rd arm for 20 and 0 degrees because it is blocked by the coil. Need to put ~6 hours of elastic run for each energy to calibrate the asymmetry measured by the 3rd arm
3) Need to study the High PMT rate issue of the tracker

  • Min:

1) Trying to produce transportation packages for the standard HRS (12.5 degrees)


4/20/2011: Present: Kalyan, Jixie, Melissa, Chao, Pengjia, Jian-ping, Alexandre Phone: Karl, Ryan

  • Jp:

1)Confirm with Karl that the plan we will use to solve out-of-plan angle shift is 9cm shift and 2.5T target field for 6 degrees of 1.1 and 1.7 beam energies.
2)There is a discussion about GEP among Jp, Doug, Guy, Jixie and Vince. GEP needs to know phi angle, which can be determined by G4 simulation
3)Need to have a detail optic run plan. JP hope Nilanga or Vince can work on this. Jp also suggested Jixie and Min to participant on this work
4)The Helmholtz coil has finally been shipped. It will arrive in 2-3 weeks. JP reminded that we need to do a survey to the target field map once it arrives. Jixie volunteer to in charge of this work.
5)Suggested Alex to carry out a teat with low current beam. Make it as an official one if needed.
6)Sign Min and Melissa to track on HRS status. They need to write down all components which is not working therefore we can fixed them and make everything ready before experiment start.

  • Pengjia:

1)Show his analysis on a LEDEX Tungsten calibration run. Check Elog entry 91 for details.

Min: 1)Trying to put septum field into the SNAKE
2)Try to create HRS transportation for 12.5 degrees HRS without target field. Then compare this with known result to make sure SNAKE work.

  • Chao:

1)working on estimating the rates and backgrounds for the 3rd arm 2)working on the XS library. EPC and QFS are ready, still need to work on Peter's inclusive model

  • Kalyan:

1)Talked to Charles Hyde and got confirm that we can use one DVCS-I proton detector tower. Need to get all necessary information and work out where to place it.

  • Jixie:

1)Finish running simulation for GEP 6 and 12.5 degrees.
2)Updated Makefile to support 64-bit Darwin system.
3)Need to repeat the analysis for 9cm shift and 2.5T field simulated data.

4/13/2011: Present: Kalyan, Jixie, Melissa, Chao, Pengjia, Jian-ping, Alexandre Phone: Karl, Ryan, Tobe

  • Pengjia:

1) Continue working on the BCM calibration. Check the figure he show in elog entry 51. https://hallaweb.jlab.org/dvcslog/g2p/51
The figure shows a spike at temperature about 24.5 degree, which looks like the beam was tripped at that time. Need to look into the beam current strip chart to understand this.
The source code for the calibration can be found in entry 19 https://hallaweb.jlab.org/dvcslog/g2p/19 A detail document about the calibration can be found here:
http://hallaweb.jlab.org/experiment/LEDEX/camsonne/webpage_calorimeter/calibration/webpagecalibrationcalorimetre.html
2)JP remind that the purpose is to find out if the tungsten can provide a 1~2% uncertainty charge. That is the goal for BCM calibration.
3)Pengjia have a meeting with Bob discussing using the HAPPEX ADC module in G2P DAQ. Bob provided a writeup. Check the entry 53 for details https://hallaweb.jlab.org/dvcslog/g2p/53

  • JP:

1) During the time G2P is running, Hall C QWEAK experiment will always own the priority which means the injector will take the feed back from Hall C. Since G2P is running at low current, the feed back from Hall C may not be good enough for Hall A. JP suggested to find out if the injector can take the Hall A feed back in the same time.
2) Suggested to find out
A) the data size of BCM and BPM data if they are push into the regular DAQ event by event.
B) what will be the dead time ?
Need to think about this off-line and discuss it again in future.

  • Chao:

1) Worked with Kalyan for the 3rd arm rates. A figure of the elastic proton cross section distribution and its dominate background has been put into elog entry 43: https://hallaweb.jlab.org/dvcslog/g2p/43.
2) Trying to pack QFS, EPC and pair production cross section routines into a library for the Monte Carlo. This is requested By Jixie. JP and Karl mentioned that the epc may not provide good result for DIS region. They suggested to use Hall C results. Peter Bosted has some codes can provide better result in DIS region, this code is now maintained by Eric Christy. Some information also available in Peter's home page: http://www.jlab.org/~bosted/fits.html

  • Kalyan:

1) Looking for some 5cm thick scintillator to build the 3rd arm. Alex mentioned that there is a gamma|proton detector used in DVCS-1. This detector is now sitting at ODU. It looks like a good one for the beam asymmetry purpose. Alex will contact Charles Hyde for it.

  • Karl and Ryan:

1) Recalculate the rates and kinematics using Jixie's fitting in elog 47. The result has been posted in elog entry 52: https://hallaweb.jlab.org/dvcslog/g2p/52 . Based on this result, it is very hard to reach Q2 less than 0.06. most of the 1.1 GeV kinematics can be reach using 1.6 GeV beam. The rates for each kinematic points decrease a lot. We need to consider
A) Removing some kinematic points B) How to reach the low Q2 points? C) How to increase the rates? Changing the beam incident angle and lift the target by a few cm? We need to think about this off-line.

  • Jixie:

Working on putting the target field and septum field into the SNAKE. Jixie has also put a few entries into the elog:
1) Release Geant4 program HRSMC v0.93. Fixed the bug in the field.
2) Simulation HowTO document is ready, check elog entry 45
3) Finalized the beam dump opening, check elog 46
4) Recalculate the optics rate: It looks like we can do the optic for 12.5 degrees, even with sieve slit. Check elog entry 48 for details
5) Provide a better fit for the angle shift due to the field. Check elog entry 49 for details.




3/30/2011: Present: Kalyan, Jixie, Melissa, Min, Chao, Pengjia, Maxime, Jian-ping, Phone: Karl, Ryan, Tobe

  • PengJia:

1) Started to analyze the Tungsten Calorimeter
2) Pengjia need to find out some constants. Refer to this document for details: http://hallaweb.jlab.org/experiment/LEDEX/camsonne/webpage_calorimeter/doc/physics-case2.pdf
3) One of the BCM cavities does not have signal. This problem is exist for long time. Alex will look at it once hall is opened.

  • Min:

1) Cross check the scattered angle shift. Min did a fast check by eyes and got similar result. She needs to check it by a small program and more carefully.
2) Put target field map into the snake already.

  • Jixie:

1) Comparing the septum field from Robin to the one used in the snake. It turns out that they are different. This septum field have a spike at R about 5 cm, Jixie have discussed this with Robin and ask Robin to check the TOSCA model. Robin will create a new map when she finish her checking. By then we need to the latest septum map into snake.
2) Coordinate Min working on the snake. Need to make sure the target field is implanted properly.
3) Fixed a bug in the Geant4 simulation program. The bug is in the target field interpolation class. There is an empty line at the end of the field map which is not supposed to be there. Due to this empty line the field values at target origin (0,0,0) are wrongly set to zeros. Therefore the interpolation in the target center give a wrong value. Jixie has fixed it and now run the simulation again to repeat all analysis done with bugged version.

  • Chao|Kalyan:

1) Estimate the 3rd arm elastic rate and background rates from epc code. The rates looks too good to be real. Chao will look further and try again.


3/23/2011: Present: Kalyan, Jixie, Melissa, Min, Chao, Pengjia, Maxime, Jian-ping, Alexandre Phone: Karl, Ryan

  • Min:

1) Made a consistency check for the SNAKE transportation code. https://hallaweb.jlab.org/dvcslog/g2p/40 The figures show that it works well. This means that Min is able to utilize SNAKE and MULDIFI to create transportation functions. Jixie and JP suggested Min to repeat this in some more end planes.
2) In the same elog entry, the last 2 figures shows that target field used in snake is totally different from the field map which is provided by SANE people. check this also https://hallaweb.jlab.org/dvcslog/g2p/42 for details

  • Jixie:

1) Show the scattered angle as a function of the detected momentum. https://hallaweb.jlab.org/dvcslog/g2p/41 This figure shows that the scattered angle will be changed a lot by the target field, which will shift all the kinematics points and also affect the rates. Jixie will make a final check and then provide a accurate information to Karl and Ryan so they can recalculate the rates.

  • Penjia:

1) Working with setup for the BCM beam test. One of the BCM cavities does not have signal. Looking into this issue.
2) New BPM electronics have been setup in the north linac, currently working but need low current to do tests.

  • Chao:

1) Working on the estimation of uncertainties due to dilutions in the target. Need more information on the acceptance.

  • Kalyan

1)Updated on the third arm. Got permission from Mahbub to use a forward tracker (used in SANE) if needed. Looking into this detector to see if this can be mounted in front of scintillators to give some position information. Also will check energy losses in in this detector.

  • Karl/Ryan:

1) Karl and Ryan will need confirmation from Jixie about the scattering angle shift and thereby shift in the kinematics. Based on the this new information, Ryan will do new estimation of rates etc.

3/16/2011: Present: Kalyan, Jixie, Melissa, Min, Chao, Pengjia, Karl, Maxime, Ryan, Phone: James

  • Kalyan:

1) Searching for probability to put 3rd arm and 4th arm (simple electron detector). Work with Jixie and found the best location for the 3rd arm and the 4th arm already. https://hallaweb.jlab.org/dvcslog/g2p/29
2)Checked with Alan and found out that there is no space left for an extra electron detector. Decided not to use 4th arm.

  • Min:

1) Succeeded to fit SNAKE trajectories. Add X0 dependence and refit again.
2) Will repeat the fit procedure using various end plane requested by Jixie.
For example, fit to get the transportation function between the following 2 end planes: target and Septum exit, target and Q1 entrance, target and Q1 exit, target and Q2 entrance ... and so on. These routines will be used in the G4 program to eliminate particles which hit the HRS wall. 3) Jixie request Min to verify the validity of the transportation functions and reverse functions.

  • Jixie:

1) G4 program is ready to run for 12.5 degrees. For 6 degree still need Min's transportation functions. Currently use the transportation routines of GDH experiment.
2) The reconstruction for current program does not work. Waiting for the reverse functions.
3)Asked Min to check the validity and provide the transportation routines.
4)Gave a tutorial to students about how to run the G4 program. Jixie agreed to post some document in the elog.

  • Maxime:

1) Tried to estimate the minimum size of the raster for CH2 target. Maxime changed to used the collision energy of the beam as the heat source. In his last calculation he used the ionization energy loss. He had sent his result to Chris Keith for comments.

  • Ryan:

1)Recalculate some of the kinematics in the proposal using some new thickness of materials which an electron will see. The results does not various too much from those in the proposal. Ryan will post his calculation into the elog later.

  • Toby:

1)Learning the Hall A softwares.

  • Pengjia:

1) Finished the estimation of the g2 uncertainty due to the target field miss alignment. https://hallaweb.jlab.org/dvcslog/g2p/13 2) Will perform a BCM test in the beam line with Alex very soon.

  • Chao:

1)Use QFS to calculate the dilution factor. Still debugging the program.

3/09/2011: Present : Jixie, Melissa, Min, Chao, Pengjia, Jianping, Maxime, Kalyan

  • Penjia:

1) Finished BCM calibration for SRC
2) Plan to modified Bob's code to read scaler variables for BCM calibration
3) Still working on calculating the g2 uncertainty due to the target spin. He managed to download MAID dsTT and dsTL cross section from web

  • Min:

1) Generated trajectories in SNAKE and managed to fit it with MULDIFI. Add a new routine pyfit into the reverse functions. She ran a program to translate the FORTRAN routines to c++.
2) There is currently no x0 dependence in the DULDIFI. Min plan to add this feature. Jixie mentioned that this should not be the priority job to do.

  • Chao:

1) Checked the epc code, he can reproduce all the plots shown in the paper. That means the cross section Kalyan calculated for proton is correct. JP and Kalyan did a quick check and verify that the cross section from epc is consistent with the data of previous Hall A experiment, 3He(e,e'D).

  • Kalyan:

1) Worked with Chao to verify epc code
2) Suggested to change to a big meeting room
3) Working on the third arm

  • Maxime:

1) Calculate the temperature of CH2 with and without the raster. Tried to find out if we can use CH2 as the optics target. His calculation shows that 50 mil CH2 will be at 136K (temperature in the center) if hitted by 150 nA 1.0 GeV Beam. Check his report for details https://hallaweb.jlab.org/dvcslog/g2p/27
2) Maxime will estimate what will be the minimum size of the raster.

  • Jixie:

1) Geant4 simulation program HRSMC v0.92 released
2) The optics rate and local beam dump opening analysis has been redone with the
new HRSMC. A few entries had been made into the Elog. Check the elog for details
3) Did a quick look at the electrons reach the HRS focus plane and also hit the coils. check this link https://hallaweb.jlab.org/dvcslog/g2p/30
4) Jixie and Kalyan look into the ep elastic events in the G4 simulation. we tried to find out where is the best place to put the 3rd arm and the 4th arm(if possible). check this entry for detail: https://hallaweb.jlab.org/dvcslog/g2p/29


3/02/2011: Present : Jixie, Melissa, Min, Chao, Pengjia, Jianping, Maxime By Phone: Karl

  • Pengjia:

1) Pengjia practiced the BPM test with the cavity BPM used in PREX this week during SRC experiment (The low current BPM test is supposed to be done by John. Currently we do not know the status of it. Pengjia will contact will john to find out the status.)

2) The N-Delta experiment (one of the SRC experiments) will have their BCM test and calibration soon. JP suggested Pengjia to practice and follow up.

3) JP suggested Pengjia to talk to Alex and find out the test plan(when, where and how)

4) Pengjia encountered with problems in HAPEX electronics. One port of the DAQ does not give correct signal except the pile up. He need to solve the problem and gain experience.

5) Pengjia is still working on the G2 uncertainty due to the target spin.

6) Pengjia need to find out the ratio of g1 to g2. Karl agreed to help him to get start with the MAID model.

  • Min: Just back from her shifts in TUNL(DUKE). Will work on SNAKE and MULDIFI to get transportation packages.
  • Chao: Showed his study on the packing factor/dilution. It was shown that the 1st order

of g2 did not depend on dilution factor.

  • Jixie:

1) Mentioned the Geant4 v0.9 released. For how to use this program, refer to this web: http://www.jlab.org/~jixie/HallA/G2P_G4Sim_V0.9_ReleaseNote/ http://www.jlab.org/~jixie/HallA/HRSMC/Menu/

2) Jixie will try to find out if we need a full size of C12 target to study the acceptance dependence on beam position.

3) Jixie will estimate how long the CH2 will survive with and without raster.

  • Kalyan: Just recovered from the RC status. Will continue working on the 3rd arm.

2/23/2011: Present : Jixie, Melissa, Min, Chao, Pengjia, Jianping, Alex, Maxime By Phone: Karl, Ryan and Toby

  • Min:

1) Min found a suspicious parameter in the snake configuration file. She found that the target field was rotated 96 degrees which make the target field orientation to a suspicious direction. She need to spend more time to understand the snake coordinate system and focus on the snake program.

  • Karl:

1)The jlabs2 is retire or will be retire very soon, so as the jlabs3. We have to make snake run in Linux box. 2)Setup the evo meeting system from next meeting so people can understand what is going on from remote

Ryan: Working on the radiation correction code. The code is now able to compile. This program will be used to calculate the radiation tail.

Karl's another student is trying to setup working environment and learn Hall A analyzer.

Jixie: 1) Released the Geant4 simulation program HRSMC version 0.9. For details refer to 

http://www.jlab.org/~jixie/HallA/G2P_G4Sim_V0.9_ReleaseNote/

There are some picture inside to show the rates for various settings.

2) Discuss the optics rates he calculated. https://jlabsvn.jlab.org/svnroot/halla/groups/g2p/Rates/g2p_optics_rate.pdf Jixie will cross check it off-line and make a final report to the target group.

Pengjia: 1) Show his calculation of g2 uncertainty due to the small deviation of the target spin. But he need to spend more time to think about his calculation.


2/16/2011: Present : Kalyan, Jixie, Melissa, Min, Chao, Pengjia, Jianping, Karl(phone), Alex, Maxime

  • Alex: Found out some electronic device (preamplifier) broken through BCM test. Alex and Pengjia will try to test it again after it fixed.
  • Penjia:

1) Penjia is looking into the analyzer get information of BCM|BPM from PREX data. Documentation is hard to find. Alex will help to search for some document.

  • JP:

1) BPM: should push to have BPM electronic tested. JP recently found out that there is one super-harp and one regular harp in HallA. The super hard can have a resolution of micrometer level, but the regular one is estimated to have the resolution of 800 micrometers. G2P need to have 2 super-harp, which is costly. He suggested to seek for improvement or better solution.

2) Suggested to do a survey for the target field if possible.

  • Jixie:

1) Upgraded the G4 simulation program to add septum entrance window and sieve slit. Jixie tried to use the G4 program to get the rates for optics but not ready to get result yet. 2) Jixie will get rates by Thursday from single arm simulation program.


  • Min:

1) Min showed her simulation result about the optics rate. Some small problem need to be solved. She will work with Jixie to get the final rates out.

  • Kalyan:

1) Continue working on checking the possibility for the 3rd arm. He is looking into the real data to get the dilution factor.



2/09/2011: Present : Kalyan, Jixie, Melissa, Min Huang, Chao Gu, Pengjia Zhu, Jianping Chen, Karl(phone), Alex

  • Pengjia:

1) Finish cabling for the cavity BPM in the hall. This cavity BPM has been used in PREX, we are now going to test it to see if it works for G2P and how well it goes. 2) Kalyan raise question about the signal splitter of the BCM if it is an active one or passive one. This splitter was used to split BCM signal into 2 lines: one is connected to the counting house another stays in the hall. Need to ask Alex|John or do a measurement to verify this. 3) Alex or John will work on the BPM test plan 4) JP suggested Pengjia looking into the PREX data for the BPM block to learn about the BPM.

Min: 1) Min showed the status about studying MUDIFI. This is a configuration file to control the trajectory: http://www.jlab.org/~mhuang/g2p/mudifi/g2p_traj2.dat (This file was also used by SNAKE to create the trajectories. For detail how to read this file, refer to the SNAKE MENU https://jlabsvn.jlab.org/svnroot/halla/groups/g2p/SNAKE/Snake_manual.pdf )


Jian-ping: 1) Reminded that we need a draft of the run plan . 2) Need to decide what kind of target we want and provide the information to the target group in a week. Jixie need to work hard to get a the result quickly.

Jixie: 1) Need to confirm with Josh what the design of current target stick is. How many target cells we can have: is it 4 large cell + 2 small cell? (2 large cells for NH3, 1 large cell for cross? 1 large cell remains empty for beam tuning?......) A)Is there any space below the bottom of the stick to use as the empty target? B)We need to find out what king of design we want and tell them.

2) Jixie need to check the following quickly: A)need to study how the target thickness affect resolution (run single arm simulation) B)Run simulation to decide what target is best for optics, C12, CH2 or Ta? (check rates, angle resolution ...)

3) Working on the Geant4 simulation: A) Continue working on the radiation background project, need beam dump shape and geometry information B) Add the following exist HRS transportation packages: (Septum+HRS) and HRS. Later on will add Target-Field+HRS) and (Target-Field+Septum+HRS) if they are ready

2/02/2011: Present : Kalyan, Jixie, Alex, Min, Pengjia, Jianping, Karl(phone)

  • Kalyan:

1) Kalyan is searching for possibility to place a 3rd arm to detector either the elastic electron or elastic proton (or both). This time he showed the estimate rates to detect the electrons at 42 degrees. Please refer to https://hallaweb.jlab.org/dvcslog/g2p/11 for details.

2) He also showed some real data at 45 degrees from BigBite http://www/~kalyan/g2p/meetings/02feb2011/

Summary: a) Electron detection at 42deg is only good for 1.1GeV, for rest of energies the rates are very low(its hopeless) b) Protons can be detected around 75deg but the S/N is very low. So may need to put a small scintillator at small angle to give coincidence with hadron arm and reduce background.

JP: 1) Discuss if we need to run Compton at such a low current. Considering the facts that A)tuning the beam through the Compton chicane always takes time, B)the Compton may not work efficiently in such a low current and low beam energy c)It takes longer time to run moller if the beam go through the Compton chicane we may not want to run Compton during G2P. But we may run it for 3.3 GeV beam at the end if time allows.

2) Discuss about the NMR coils. We did not understand the uncertainty and effects of the "uniform" NMR or that of the "edge" NMR. He suggested to verify which is better and what is the effects compare to the EG4 data. We need to run simulation to understand the radiation effect of that. A quick way i


  • Pengjia:

1) Plan to write tech note for the Beam Position Measurement 2) He gave a presentation about beam position calibration, see the slice here: http://www.jlab.org/~pzhu/report0202.pptx


  • Min:

1) Will work on the 3rd arm with Kalyan, she will look into the Bigbite performance in the SRC experiment 2) Continue working on snake and MUDIFI program

  • Jixie:

1) Show some visualization figures for the Geant4 simulation. Currently there is some bug on the transverse configuration. Jixie is working on that. 2) Will simulate the NMR coil for radiation.


1/26/2011: Present : Kalyan, Jixie, Melissa, Alex, Min, Pengjia, Jianping, Karl(phone)

  • Jixie:

1)The coil will block almost half of the acceptance of one arm for the configuration that the field is 80 degrees with the beam and HRS at 6 degrees. Refer to https://hallaweb.jlab.org/dvcslog/g2p/9 for details. For HRS at 12.5 degrees, only single arm data will be available. Need to mention this to Doug and Guy. Alan is waiting for the decision to finalize the design for the scattering chamber entrance window. 2)Still waiting for input of beam dump for the Geant4 simulation

For 74 degree and solid angle 60 mSr: The elastic Pr rate is about 4 kHz; the total inelastic rate for Pr in momentum range 0.25-0.4 is about 270 kHz.

Need to find out a way to reduce the inelastic rates. Increase the momentum range to 0.280Gev/c may help...

  • Jp: About the BCM|BPM of the beam line, Jlab may pay 60K for it???
  • Pengjia: Talked about the target cooling took place at UVA. The

maximum field provided by UVA solenoid is 5.0032 Tesla. He showed some pictures of the solenoid, the microwave generator, the pump system. The target was cooled down pretty smooth. He will summarized it and put it onto the web for next meeting.

  • Min: Working on the MULDFI program. Discussing the effects introduced by the 2cm raster. Angle resolution is more important than the position resolution.


1/19/2011: Present : Kalyan, Jixie, Melissa, Karl, Min

  • Kalyan : Working on third arm elastic rates. Looking at 2 options,

both on beam left: 1) Bigbite detecting protons at 74 degrees. Issues: manpower to install, no identified power supply and possible issue of overtaxing the power budget to the hall (Ed Folts). Guy may have power supply at Berkley. Jixie will follow up to see if power budget is real problem. 2) A small calorimeter at 42 degrees to be used as electron detector on the platform about 2 m from the can. Pros: simple design, little tech support needed. Cons: rate will be very low. PMTs near target field might have problems. Goal is to have a decision to present at the next collab meeting.

  • Jixie: Working on the Geant4 simulation. Has created scattering

chamber and included the UVa target field map. Waiting for more information on the beam dump design. Initial goal is to look at radiation in the hall. Intermediate goal is to look at acceptance blockage by the target coils. Later, will be able to look at physics and issue of radiative tails at low Q2. Jixie will talk to Whitney Armstrong from Temple who created a geant 4 simulation of the target for SANE. Jixie is working with Min on SNAKE. John having difficulty to transfer code from solaris to linux. Will talk to Doug about impact of acceptance blockage on gep (target at 80 deg) for 12.5 degrees scattering.

  • Min: Working on the fitting for SNAKE. Also interested to get

involved with the 3rd arm study.

  • Melissa: Starting to look at target and detectors.
  • All: Discussion of manpower and projects in need of manpower.
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