Difference between revisions of "G2p Analysis Minutes"

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==3/1/2013==
 
==3/1/2013==
  
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Present: Jixie, Jie, Min, Melissa, Chao, Karl, Vince <br>
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Present: Jixie, Jie, Min, Melissa, Chao, Karl, Vince, Kalyan <br>
 
By-Phone: Ryan, Toby, Elena Long, Alex <br>
 
By-Phone: Ryan, Toby, Elena Long, Alex <br>
  

Revision as of 15:53, 14 March 2013

Minutes of the weekly analysis meetings

Agenda



3/8/2013

Present: Jixie, Jie, Min, Melissa, Chao, JP, Kalyan
By-Phone: Ryan, Toby, Elena Long, Karl, Pengjia

General discussion

Feature presentation:

  • Melissa:
    • Moller write up (By Sasha) is ready in the wiki. (G2p wiki-> Analysis ->Moller)
    • Beam polarization run by run result is ready. The bleed through from hall C in terms of beam ratio

was less than 1%. The beam polarization for the bleed though was as small as several percents. We can ignore
this part in the analysis. (Melissa is very kind to provide a run by run table.)

    • Tech note for colorimeter and Cherenkov efficiency is ready to review.
  • Chao:
    • Working on the simulation packages. Optimized the drift in field module by dynamically changing the

step length.

    • Present the idea that how we determine the vertical interaction position which is needed to do reconstruction.
    • Check how large the distribution center will move after weight by cross section. See details here.
  • Min:
    • Kept tuning snake model to match real spectrometer. Made the following changes.

A) Solved a few bugs of position offsets.
B) Extended septum box to cover more field region, aiming to reduce the BdL lost
C) Adding HRS offsets using survey results
D) Using the real Q1 currents

    • With this update, the center hole hits on focal plane have about 8.7 mm shift in y position if match the phi angle

or have 8.5 mrad shift in phi angle if match the y position. See details here.

  • Pengjia:
    • Present a slice for the beam position for the optics data that were taken on March 14, 2012. It turned out that

the beam position was not centered. It had 4.4 mm shift to the left and 1.5 shift to the up.

    • The slice also indicated that BPM B is not stable. Pengjia agreed to find a way to avoid unnecessary fluctuation.
  • Jixie:
    • Present the study of how well can we determine the central value for a distribution.
    • There is no good event by event resolution for the scattering angle when the target field is on. We will reconstruct

FP hits only to the target plane. By comparing the central value for the scattering angle and also the cross section distribution
between cross section weighted or unweighted situation, we can tell how well we can determine the central value.
Jixie did this comparison in several HRS momentum settings. The work show that we can determine the central value better than
1% using snake model. To reach this precision in real data, we have to calibration the reconstruction to avoid any offsets and bias.
See details here.

3/1/2013

Present: Jixie, Jie, Min, Melissa, Chao, Karl, Vince, Kalyan
By-Phone: Ryan, Toby, Elena Long, Alex

General discussion

Feature presentation:

  • PengJia:
    • Merged HAPPEX decoder to g2plib. The beam packages will use HAPPEX decoder by default. Before it is

fastbus. HAPPEX has much better resolution than fastbus if fastbus is using auto gain. Pengjia compared
the resolution of these 2 daqs at various situations. See details here.

    • Found an optics run (22259) that happex and fastbus did not agree with each other. PengJia agree to

to check all optics runs to see if this problem occur or not.

  • Ryan:
    • Tried to use PengJia's BPM package. Need some more work to get it right.
    • Practiced Ytg optimization.
  • Jie:
    • Updated the multiple tracks efficiency analysis.
    • The goal is to find the ratio of at-least-one-good-track event in two-track events under normal cuts.
    • There is a large deviation between L-HRS and R-HRS in previous talk. Jie found that it was because the

database of the prl1 and prl2 geometry was wrong. After manually correct the data, L-HRS and R-HRS agree
well to each other. See his nice work here.


2/22/2013

Present: Jixie, Jie, Min, Kalyan, Melissa, Chao, JP, Alex
By-Phone: Ryan, Toby, Elena Long, Karl

General discussion

Feature presentation:

  • Melissa:
    • Got the asymmetry result run by run from QWEAK Compton polarimetry. Match it

to the g2p run by run according to the time stamp. Will use this asymmetry table to
to check if there is any fluctuation in the beam polarization. See details here.

  • Chao:
    • Working on building the single arm simulation program, testSNAKE. Add field and field integration modules.
    • Test the method of "Match reconstructed trajectory to Beam trajectory to get the interaction point".

The results shows that this method does not have a good event by event reconstruction at all.
See the slices for details.

  • Jixie:
    • Test the trajectory matching method independently. Jixie generated events at 3 2-mm-Z-slices: 10cm upstream,

target center and 10 cm downstream. The results show that the matching method can not find the interaction point
at all. See details here.

  • Min:
    • Continue working on creating a snake model that can represent g2p setting. Phifp and Yfp can not match at the same time.

Need more efforts. See this link for details.

  • kalyan:
    • Updated the analysis status flow chart.

Most of the task is done. BPM and slow raster is in progress. Straight through optics is 80% done.
It depends on BPM calibration.

2/15/2013

Present: Jixie, Jie, Min, Kalyan, Melissa, Chao, JP
By-Phone: Ryan, Toby, Pengjia, Elena Long, Karl , Alex

General discussion The Fall DNP (October 23-26, 2013) for this year will be held at Newport News. Can we have result by then? Answer: Not likely.

Feature presentation:

  • Toby:
    • average N sweep area to get the mean value
    • Systematic errors came from Magnetic field drift, temperature fluctuation, NMR drift and so on

will be added to each sweep later.

    • Systematic error is about 2-3%. Will details later.
    • will go back through the TE measurements and using a more rigorous chi2-minimization technique to exclude poor data

See details here.

  • Ryan:
    • Provided a root library to connect to the mysql database.
  • Jie:
    • Updated on the two-track analysis for both arms. There is about 20% deviation between left and right arm

on the ratio of one good track out of two-track events. This issue is still over there. Jie will keep working
on it. See details here.

  • Pengjia:
    • Generated transport function from BPM to target center for field is on situations.
    • Found a better way to determine harp noise.
    • Updated BPM packages. Used the uncertainty of each single harp measurement as the weight in the TMinuit fitting.

The BPM uncertainty (preliminary) is about 1.5 mm for position and 1.4 mrad for
angles when target field is off. There will be some room to improve.

2/08/2013

Present: Jixie, Alex, Vince, Jie, Min, Kalyan, Melissa, Chao, JP
By-Phone: Ryan, Toby, Pengjia, Elena Long

General discussion

Feature presentation:

  • Melissa:
    • Finalized the cut and efficiency analysis. The pi/e ratio after the optimized cut are

now 0.4% for both arms. See details here.

    • Melissa agreed to write some note about this job.
  • Toby:
    • The previous R-HRS cooking used a wrong calibration file for the preshower. Need to do a recook.
  • Min:
    • Working on tuning the snake to match the real data. Min tried to turn the quadrapole and

dipole such that the simulated variables in FP match the real data. But this is wrong. She will
go back to the original dipole setting and try to tune septum fields.

A ZERO and FIRST order post processing correction have been made to the none raster snake model. The Zero order correction
can remove most of the offsets between real data and snake model. The FIRST order correction can make it event better.
This is just a machinery check to make sure the program work fine. Will present this kind of job once Min finish tuning SNAKE.
From the ZERO order correction we can see that Q1 in the snake model need some tuning.

2/01/2013

Present: Jixie, Vince, Jie, Min, Kalyan, Melissa, Chao, JP
By-Phone: Ryan, Toby, Pengjia, Karl

General discussion

Feature presentation:

  • Ryan:
    • Present the result of quality check:

LHRS: 956 good runs (73%), 104 junks(8%), the others have some
issues which might be useful with extra treating.
R-HRS: 798 runs are good (68%) and 109 are junks(9%)
See details here.

  • Pengjia:
    • Improved the code which is judge whether the beam is drifting.
    • Updated MUDIFI program to export c code with error transfer function, refit the BPM transport functions.

See Pengjia's talk here.

  • Jie:
    • Working on the multi-track analysis. Check the status here.


1/25/2013

Present: Jixie, Vince, Jie, Min, Kalyan, Melissa, Chao, JP, Katherine
By-Phone: Ryan, Toby, Pengjia, Karl

General discussion

Feature presentation:

  • Chao:
    • Add Rotating Coordinate System (RCS) to Focal Plane variable in the code. In the real DB, the reconstruction

takes the variables in the RCS, not the Transport Coordinate System(TCS). With this modification, the reconstruction
between simulation and real DB agree with each other better. But still have noticeable difference.

    • The forward transport of the snake model still have some offset to the real detected FP variables. Need to correct

the offsets.

    • Checked the first order matrix elements for both real DB and SNAKE backward model. The real DB matrix first

order elements for <theta_tg|y_fp> and <theta_tg|phi_fp> seem too large. See details here.

0.5% relative uncertainty of the scattering angle, the uncertainty of the energy difference between 2 peaks
in the pointing measurement should be 45 keV.

    • Present the initial pointing result [1].
  • Melissa:
    • Worked on optimizing the PID cuts for good electrons. She has done that for a few momentum settings. Need to

go through all the momentum settings. See details here.

1/18/2013

Present: Jixie, Vince, Jie, Min, Kalyan, Melissa, Chao, JP
By-Phone: Ryan, Toby, Pengjia, Karl

General discussion

From next week, we will have the weekly analysis meeting at 10 AM every Friday.

Feature presentation:

  • Ryan:
  1. Presented the optics calibration for 5T longitudinal field data set, R-HRS.
  • Pengjia:
  1. Presented the status of BPM calibration for straight through data set.

Pengjia was trying to find the time interval that the beam is not stable and treat
them separately. He is using the 1000 events and 7500 events moving RMS to determine
one whole run into several period. See details here.

  • Jie:
  1. Took an initial look at multiple tracks at the colorimeter. Jie was suggested to add

the electron cut then repeat the analysis. See details here.

1/8/2013

Present: Jixie, Vince, Jie, Min, Melissa, Kalyan, Chao, JP, Karl
By-Phone: Ryan, Toby, Pengjia

General discussion

  • APS abstract deadline is this Friday. The deadlines for GHP and INPC are also very

close. Those who want to attend these conference please prepare the abstract as early as possible.

Feature presentation:

  • Min:
  1. Presented the Ytg optimization for R-HRS using NO target field data. See details here.
  2. Prepared the non-raster SNAKE backward model for Chao.
  • Chao:
  1. Working to compare the 1st order matrix element between REAL DB and SNAKE backward matrix.
  2. Chao has a long term plan to make a simplified version of HRS simulation using existing modules.
  • Melissa:
  1. Updated the result of Detector efficiency and Cut efficiency for L-HRS. See her latest result here.

Will do the R-HRS next.

  • Toby:
  1. Working on replay script. The output ntuple is too big. Students need to discuss and determine what variables should

be kept. Jixie suggested to include the unfinished BPM reconstruction in the cooking train at this moment. To save time and
space, do not cook optics runs.


April-Dec 2012

Minutes_Apr2012_to_Dec2012

Jan-March 2012

Minutes_Jan2012_to_Mar2012

July-Dec 2011

Minutes_July2011_to_Dec_2011

Jan-June 2012

Minutes_Jan2011_to_June_2011

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