G2p Analysis Minutes

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Minutes of the weekly analysis meetings

8/10/2011: Present: Karl, Jixie, Chao, Pengjia, Min, Vincent, Jie By Phone: Mellisa, Ryan, Toby

  • Karl:

1) Target is not cool down yet, still filling helium. Ryan, Toby and Mellisa are already there.
2) Can not find 2 cm SC
3) Got approved that we will have 12 days of 1.7 GeV beam (may be a old news to someone).
4) Try to extend to run the experiment during Christmas

  • Jixie:

1) Talked to Bogdan and Albert for 2cm SC. There is no EXTRA 2 cm SC that can be used for us.
2) Talked to Brad and Bob about 10K Hz DAQ rate with ADC. Both of them are said there need some
efforts to make this happened.
3) Finalized the 3rd arm design:
A) Since 2cm SC is not available, we will switch back to 1 cm SC for the 1st plane;
B) The neutron shielding will be 30 cm thick and we will use the exist borated plastic;
C) The width of of SC plane will be extended from 6 to 8 inches;
D) We will put a removable 2mm aluminum shielding to shield low energy background from the target.
We will not use this shielding for 1.2 GeV. For 1.7 and 2.3 GeV, we will use it only if the DAQ rate
can not reach 10k Hz
E) We changed the detected energy range for 1.7 and 2.3 GeV.

4) Calculated the maximum raster size 9requested by Karl): It is ok to extended to 11 mm.
size assuming 25.4mm target cell diameter.
We will have the target cell diameter of 27mm, [1], which will allow to
extend to 11.5 mm.

  • Chao:

1) Simulated the 3rd arm. There is a bug in calculating the asymmetry. Need to recalculate the time
2)After fixed the bug in the code, found the final position and rates:
Beam(GeV) Mom_Range(MeV) Hoffset(cm) Voffset(cm) Time(hours)
1.159 270~410 6 0 9.5
1.706 320~460 0 -20 9.9
2.257 320~460 0 -40 7.1
Please note that the detector efficiency is not considered yet.
Check details [2].

  • Min:

1) Solve the snake problem in linux by using -fno-automatic option.

  • Pengjia:

1) Will looking to the low current data taken during Xgt2 to check noise of adc in BCM|BPM
2) Arne will test the tungsten colorimeter with heater some time next week
3) The ring buffer is working, will move on to read ADC and helicity signal, and TCPIP program which
will be used to communicated between the ring buffer and HRS DAQ

  • Jie:

1) Shown improved result. After optimize the fitting ranges, the variation of data to tosca reduce to 3%,
and the position offsets are all within 1 cm. Check | this for details.

8/3/2011: Present: Karl, Jixie, Chao, Pengjia, Mellisa, Vincent, Ryan, Toby, Jie

  • Karl:

1) Organized student go to UVA to participant the target cool down

  • Jixie:

1) The detector response function is ready in the Geant4 simulation program.
| Energies deposited by elas proton
| Hits in neutron simulation
| Total energy deposited by neutron. (Please note that the top panel is still for the 2nd plane, not the 1st plane.)
The energy deposited into the 2nd plane indirectly from the neutron is about 188 MeV per 100K 2.3 GeV electrons
or 160 ns with 100 nA beam current. It truns out we must have the neutron shielding!

2) To shield the neutron, 20 cm thick plastic (Polyethylene) can block 80~85% of the neutron flux.
Check detail here: [3]

3) Third arm detector design: Al confirm that we can put 20 cm thick plastic shielding.
The detector will be located 70 degrees, 2.1 meter away from the target. The SC plane size is 6'X 24',
with rotation by the vector (r=1, theta=70, phi=0) about 36 degrees (for 5T target field) or 18
degrees(for 2.5T target field). The 60 degrees of rotation about Y axis is not necessary since the shielding
for neutron is in place. The first layer of SC will be 2cm, and the 2nd layer will be 5 cm or 2 inches.
We need to find 2cm scintillator. The center position for each beam energies are the following:
1.159 Horizontal_offset = 6 cm, Vertical offset = 0 cm OR Horizontal_offset = 0 cm, Vertical offset = 18 cm
1.706 Horizontal_offset = 0 cm, Vertical offset = -21 cm
2.257 Horizontal_offset = 0 cm, Vertical offset = -15 cm
The position can allow 1~2 cm off, and the angle can allow 2 degrees off.
4) Have already inform Al with this design.

  • Chao:

1) Ran Geant4 simulation for the 3rd arm. Verified the rotation and position.
2) Recalculate the rates. It will take about 14, 10, 7 hours to measure Pb*Pt to 5% uncertainty with 1.2,
1.7 and 2.3 GeV beam. If we increase the SC wider it will shorten the time for 1.2 GeV but longer the time for
the others due the the signal to background noise get worse. We still need to optimize the design.

  • Ryan:

1) Working on trigger on S1m
2) Looked in the Y distribution of S0, it is about 15 cm, it seems ok for acceptance. | Figure 1 | Figure 2
3) Got the timing module working after replacing the broken cables. Bob suggested to unplug HRS cable and reconnect them.
4) Will work on the HOWTO wiki pages

  • Toby:

1) Checked the probe with known field in the magnetic group with Jixie, Chao and Jie. Both the 3-axis probe and
the axial probe seems within 1% accuracy. But we did not check the variance of the axial probe in rotation.
Plan to do this in UVA.
2) Determined the current ratio to be around 1.0. Jixie suggested to check again.

  • Jie:

1) Improved the field analysis result. He analysis the data X_table=44 or X_table=46, which is most closed to the z axis.
The new current ratio is 1.151, the position offsets are Xoff~=1.2 cm, Yoff=-0.5 cm, Zoff=0.4cm. Rotation and Xoff is not
sensitive at all in this data set because the field is almost flat when x is closed to 0.
Check the detail here: http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/fieldmap.pdf
2) Will use large X data to fit for rotation and Xoff.

  • Min:

1) Tried to pull fortran routines from cern packages. But too many to pull! Jixie suggested stop doing this.

  • Pengjia:

1) Successfully build the ring buffer to store BCM|BPM signal on HAPPEX DAQ
2) Will post the target connection diagram which can help to understand the target cool down. Check Elog entry 124
for detail https://hallaweb.jlab.org/dvcslog/g2p/124


7/27/2011: Present: Karl, Jixie, Chao, Pengjia, Mellisa, Vincent, Ryan, Toby, Jie

  • Jixie:

1)Neutron flux simulation.| details
There will be about 1.3~1.5 neutrons for each 2.3 GeV electron hitting the local dump.
For 6'x24' 3rd arm detector located at 70 degrees and 2.1 meters away from the target,
there will be about 0.0012 neutrons per 2.3 GeV electron. If converted to rates,
it will be about 800 MHz @ 100 nA beam current. This result has been confirm by a FLUKA program ran
by Lorenzo Zana (who is checking the radiation for PREX2).
Jixie will work on shielding the neutron. 2)Working on third arm simulation. |details
If rotated the 3rd arm by Y axis with 60 degrees (the the SC plane will be 10 degrees with
respected to X axis), we can have 3 advantages:
A)reduce the neutron flux by a factor of 5 (=sin(70deg)/sin(10deg))
B)do not need to cut the scintillator plane
C)effective thickness doubled and will have better ability to cut ADC for triggers. (need to simulate ...)
But it require more space in the target platform. Need to check with Al

3)Can not understand how the neutron will affect the 3rd arm trigger without the detector response
simulation. Jixie will add detector response into the Geant4 simulation.

  • Chao:

1) Working with Jixie on the 3rd arm simulation. Confirm the rotation angles and tried to find
the best positions for each beam energies.
2) Recalculated the rate for the 3rd arm.

  • Jie:

1) Tried to improve the analysis on the target field

  • Min:

1) Checked the self consistency of the HRS transportation packages.
2) The SNAKE works only in SunOS but not. MUDIFI works on jlabl2 but not on jlabs3. It was assumed to
be the cernlib problem. Karl suggested to pull the needed fortran routines out of cern packages and
build a stand-alone snake program.

  • Mellisa:

1) Finished checking the Cherencov. Will move on to check the ADC signal of pre-shower and shower.

  • Ryan:

1) Checking timing for L1A (Level 1 acceptance) 2) Working on the trigger on S1m

  • Toby:

1) Optimized the fitting range in the field analysis


7/20/2011: Present:Karl, Jixie, Chao, Pengjia, Mellisa, Vincent, Ryan, Toby, Alexandre, Jie Liu

  • Jixie:

1) The design of the 3rd arm:
A) We need to place the 3rd arm at 70 degrees, not 72. We also have to move the detector
from 1.5 meter to 2.1 meter such that the local dump itself could block some background.
B) | Figure 1 shows the hit positions on the SC plane. The distribution look like a rotated strip.
In order to select a small range of theta, the SC need to be rotated to some angle.
C) | Figure 2 and | Figure 3 show the hit position for protons within and out of the theta range.
Please note that these protons are generated in a flat distribution of theta and Energy.
they are not elastic proton. Jixie will run with elastic proton again to check the rotation.
D) We might need to cut the SC from 12 inches width to 6 inches.
E) JP mentioned that it might help if the SC plane be rotated about Y axis by 70 degrees.
With this rotation the whole SC will have minimum cross section area facing the local dump.
2) Still working on neutron flux simulation.

  • Chao:

1) Simulate the 3rd arm detector located at various distance from the target (1.5, 1.75,2.0, 2.25 meter).
The detector size in the simulation is 6' x 24'. According to his result the dilution factor is about 17%
and the total time to accumulate 5% accuracy data is about 9 hours.

  • Min:

1) Check the no target field HRS transportation code

  • Pengjia:

1) learning the HAPPEX DAQ

  • Toby:

1) Show field analysis result on the can surface data set. After improve, the variation of measured field
to the map are within 1%. But the position offsets are still in 2 cm level. This analysis used only point A
position to calibrate all the data set, which leaves room for further improve. Jixie ask Toby to check
the code carefully.

  • Jie:

1) Show field map analysis. His result does not agree with Toby's.

  • Ryan:

1) Working on mapping the HRS HV. Finish ROC3 and ROC4. Check Elog entry 122 for detail:
https://hallaweb.jlab.org/dvcslog/g2p/121
2) Will work on DAQ with Alex
3) Will check PMT signal for S1 and S2m

  • Mellisa:

1) Working of the safety documents which is drawn from SANE group.
2) Checking the Cherencov, found the ADC for 1 photon-electron, but this result still need to be improved.

7/13/2011: Present:Jian-ping, Jixie, Chao, Pengjia, Mellisa, Vincent, Ryan, Toby, Alexandre, Jie Liu, Karl

  • Mellisa:

1) Continue checking the Cherencov detector. Applied geometry cut to the ADC. She need to find out
the ADC value that 1 PHE corresponding to. Check her plots in the Elog, Item 120:
https://hallaweb.jlab.org/dvcslog/g2p/120

  • Toby:

1) Showed the preliminary result for the field map analysis with the can surface data set. Most data
points are within 6% variation. But the position offsets are as large as 2 cm.

  • Jie:

1) Showed his result of the field map analysis. Most data points are with 10% variation to the
TOSCA map. Jie's result does not agree with Toby's in position and current ratio. Both of them are
requested to check their results more carefully.

  • Pengjia:

1) Tried to build ring buffer in HAPPEX DAQ. Will do the tungsten calorimeter calibration in August.

  • Ryan:

1)Looked into the HV for HRS
2)Finish the splitter box. Check Elog entry 121 for detail: https://hallaweb.jlab.org/dvcslog/g2p/121

  • Chao:

1) Tried to learn and run the Geant4 simulation for the 3rd arm.

  • Jixie:

1) Looking into the neutron background data provided by Pavel. 2) Designing the 3rd arm.

7/6/2011: Present: Jian-ping, Kalyan, Jixie, Chao, Pengjia, Mellisa, Vincent, Ryan, Toby, Alexandre, Jie Liu

  • JP:

1) Discussed the run plan with QWEAK group, ask for 12 days for 1.7 GeV. Not be granted yet.
Currently Hall C allow only 5 days, or If they are down then we can take the time for 1.7 GeV.
The plan is still under discussion.
2) If Hall B is not available, we need to be able to run 1.2 GeV. We should be very flexible and ready for changes.
3) Karl has the readiness review available. Everyone is encouraged to read and comment.
4) JP will leave from 7/22 to 8/17. Kaylan will leave to India from 7/8 to 7/29.
Alex will on vacation from 7/23 to 8/11. Karl will be on site from 7/11.

  • Min:

1) Just back from the summer school. Will continue working on the HRS package issues.

  • Chao:

1) Taking the detector geometry into account, recalculated the background of the 3rd arm using the epc code.
2) Discuss the 3rd arm design: 12 inch width will accept +/-4 degrees in theta. With such a wide
range it will take about 16 hours to measure Pb*Pt to 5% accuracy. It is too long ...
3) Finish the target field measurement with Jixie and Toby.

  • Pengjia:

1)Leaning HAPPEX DAQ, will use it for BCM and BPM
2)will do calorimeter test. The tungsten calorimeter will eventually used to calibrate BCM.
3)Learning how the Harp work and how to use it to calibrating BPM.

  • Toby:

1) Finish Target filed mapping with Jixie and Chao.
2) Working on analyzing the field mapping data.

  • Ryan:

1) Working on Left HRS trigger
2) Will check the material of the target with Josh

  • Mellisa:

1) Checking the Cherencov detector in HRS. Try to find how many photon-electron (PHE) each PMT has in the Xgt2 data set.
She need to apply the geometry cut and try again.

  • Jie:

1) Analyzing the filed measurement data.

  • Jixie:

1) Just Finished the field measurement with help from Chao and Toby. Pengjia and Jie also provide appreciable help.
2) Measured the field in 2 ways. One is measuring the field on the can surface with an axial probe (borrowed
from Josh) fixed in a aluminum block.
http://www.jlab.org/~jixie/HallA/meeting/FieldMeasurement/IMG_0804.JPG
Another is measuring the filed with a 3-axis probe on the translation table.
http://www.jlab.org/~jixie/HallA/meeting/FieldMeasurement/IMG_0800.JPG
The survey group came to the target lab and survey some positions. Just got the survey data yesterday.
Jie and Toby are working on analyzing the field map measurement. Jie is focus on translation table data set
and Toby is working of the can surface data.
3) Talk to Pavel in the Rad. Con. group for the neutron background simulation. Pavel will provide
the neutron distribution and model information such that Jixie will be able to work on radiation calculation.

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


  • Pengjia:

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

  • 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) Tried to test the magnetize effect of the translation table. Replaced some steel bolts and nuts with plastic ones. Toby and Chao will make a coil to test the stainless steel.
3) Running simulation to get local beam dump opening for Al. But the HRS transportation routines from Min do not work.

Minutes_Jan2011_to_June_2011

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