Minutes Jan2012 to Mar2012
2/15/2012: Present: Jixie, Min, Kalyan, Pengjia, Ryan, Melissa, Jie, Karl, Vince, Alex, JP, Aiden, Doug, Moshe
- JP, Karl:
1) We will have daily meeting in the 2nd floor of the counting house @ 4:15 PM from next Monday.
2) Aiden will be the 1t run coordinator and he will book the meeting room.
- Doug:
1) GEP will change to 6 deg 5.01 target field. No 2.5T target field for GEP now.
- Vince, Ryan, Jie, Melissa:
1) 70% of the electronics do not work any longer due to accident that the voltage pin switched
in the power supply. Good news is that we have some spare electronics and know how to replace them.
2) Left HRS DAQ will be rebuilt in the rest of this week.
3) Remote rest on ROC1 is ready
- Moshe:
1) Working of GEP simulation.
- Pengjia:
1) Show beam position reconstruction plan.
- Min:
1) Tuning quardroples for both arm with snake. A report is here. Try to finalize them this week.
- Chao:
1) A write up about the g2p helicity is ready here.
- Jixie:
1) TOSP for target field measurement is ready for signature. It has been printed out and handed to Chris Keith.
2) Got new septum tosca map (reduced gap) from Robin. Will update G4 simulation and simulate the acceptance change.
3) Will update optics plan.
2/8/2012: Present: Jixie, Min, Kalyan, Pengjia, Ryan, Melissa, Jie, Karl, Vince, Alex
- Toby:
1) Target installation is going well. Pumping the vacuum right now.
2) Will work on selecting output tree leaves for the replay program, under help from Vince.
- Vince, Ryan, Jie, Melissa:
1) Working on scaler scripts. Will put some useful parameters into mysql database.
Alex can help to set up mysql database.
2) The 3rd fastbus crate for R-HRS is now under installation.
3) Vince reported that 2 of the 3 fastbus crates of the L-HRS saw only 4.7v (instead of 5v) from
the power supply, while the other saw 5v. All these 3 crates connected to the same power supply.
4) Remote power cycling for the happex crates is available now. See the detail here.
- Min:
1) Tuning the quadrapoles for R-HRS.
- Pengjia, Chao:
1) Finished the helicity test, both gave a report. Pengjia's report is here.
Chao's report is here.
2) In pengjia's report, he found that there will be double peak problem if connect V2F while copying
BCM signal. Need to spend some time to understand it.
- Jixie:
1) TOSP for target field mapping was sent out for another review.
2) Updated simulation geometry: adding aluminum top, back and bottom plates to surround local dump.
the platform was also added. This update is mainly for simulate the radiation damage on septum coil.
3) Simulation result of adding shim into septum will be found here.
- Kalyan:
1) Will coordinate another beam charge asymmetry test with hall-C and moller again when beam is available.
2) Working on puting lumi into the happex adc in the R-HRS. Need to change the ADC from voltage mode to
current mode.
2/1/2012: Present: Jixie, Min, Kalyan, Pengjia, Ryan, Melissa, Jie, JP, Vince, Alex, Aiden
- JP:
1) Decided to add 2 one-inched shims into septum. May cost additional 3 days of installation.
2) New design of the chicane finished. Will be machined soon
3) Traget field direction is of importance, especially for GEP. Need target group to check this before run.
- Pengjia, Chao:
1) Working on the helicity issue
- Min:
1) Finished VDC T0 calibration.
2) Analyzed the 600A septum data, looking for the elastic peak. See details here.
3) Tuning Right quadrapole. Need to turn to John for help
- Toby:
1) Finished irradiating 16 cells of NH3 target at NIST. In total we have 24 cells now. See details of these
cells here.
2) Scattering chamber installed onto the platform. Target insert also installed. NMR tested.
- Ryan, Vince, Jie:
1) Need a serial cable for LHRS ROC5 VME5100 CPU
2) Jack will install the 3rd fastbus crate for R-HRS
3) Happex DAQ does have a way to reboot remotely. However the subnet for the hareboots belong to MCC, not Hall A. Need to
change it to Hall A subnet or add additional reboot switches.
- Melissa:
1) Updated wiki by adding 'expert shift' section, check details here.
2) Looking into the 2nd peak issue of the TDC of S2m in both L-HRS and R-HRS
- Jixie:
1) TOSP for target field measurement already sent out for review
2) Simulated septum acceptance after adding 2" shims
3) Updated simulation geometry for accurate radiation damage simulation
4) Test artificial beam charge asymmetry with moller polorimeter. Check result here.
1/25/2012: Present: Jixie, Min, Kalyan, Pengjia, Ryan, Melissa, Jie, JP, Vince, Alex
- Pengjia:
1) Try to test the helicity and beam charge asymmetry with artificial signal
- Melissa:
1) Analyze the double peak issue in GC's for both spectrometers. The 2nd peak (small one) comes from single PHE
events, which hit the edge of the mirror. Check here
for details.
- Ryan:
1) Finished the model to predict the dead time.
- Vince, Jie:
1) Working on remote reset for HAPPEX DAQ. Bob mentioned it might already exist, suggests to double check.
2) Jack plans to installed the 3rd fastbus crate for R-HRS
- Kalyan:
1) Bogdan said that the the resistor should not be used in the filter for ADCs. Need to double check before removing them out.
- Min:
1) Learning how to tune quadruples. check her xls sheet here.
- Jixie:
1) Preparing the TOSP for target field mapping
2) Writing the final OPTICs plan.
3) No more septum field measurement is needed. TOSCA model is proved to be wrong. With current setting, 1000 A
power supply current can run only 2.32 GeV. Need to increase the current otherwise will lost several kinematics points.
1/18/2012: Present: Jixie, Min, Kalyan, Pengjia, Toby, Ryan, Melissa, Jie, JP, Vince, Alex, Chao Gu
- JP:
1) Javier is writing the readiness review report, will be ready soon. There is no major
issues, just a few small questions and recommendations.
2) All documents have to be ready by Feb. 3rd, 2 weeks before start date.
3) Another irradiation will take place at NIST next week. Toby, Chao and Pengjia will be
the candidates to help over there. 3 of them and all students should try to learn the target
as much as possible and become experts
4) There will be 4 tests during g2p run. Gas CC test for A1n, gas CC and PMT test for SOLID,
GEM test and MRPC test.
- Vince, Jie:
1) Left VDC is now turned off for installation of gas bubblers.
2) Checked the remote reset for all left and right HRS crates. HAPPEX does not have a remote reset yet.
3) Jack will install a 3rd fastbus crate on the Right HRS
4) Left HRS FASTBUS reset is not working. Jack will work on it once parts have arrived.
- Melissa:
1) Found double peaks on GC TDC distribution for both Left and Right HRS commissioning data.
Need to spend more time to isolate those event and study it.
- Kalyan, Ryan, Pengjia, Chao, Toby:
1) Ryan is creating a model to predict the dead time for HRS DAQ. Most of the dead time came from the HAPPEX
DAQ, which cannot run in buffer mode.
2) Pengjia showed the result of beam position determination. The project is trying to predict the beam
position at the target by fitting it as function of position at BPM1 and BPM2. In the result raster is not
considered yet. Pengjia will also calculate the systematic uncertainty of it.
3) Chao and Toby showed the beam asymmetry measured by Hall C, which is about 5%. Their analysis shows that
the same measurement from Hall A is about 2%. After deep discussion in the meeting, we came to a realize that
there could be a hardware problem or a decode problem in the helicity DAQ. Pengjia will have to find out a
way to debug the DAQ. Chao and Toby will continue communication with Hall C and also debug the decoding part.
4) Chao reported that the remote control for 3rd arm discriminator is ready
5) Toby reported that one of the target nose have problems and was sent back to machine shop. Target group found
that the longitudinal entrance flange restrict to GEP to run the beam at 7 degrees.
6) Kalyan mentioned that the on-line prediction of helicity state should not be always on. It might affect
Qweak( need to find out how). We will have to have a switch and run it in short interval only for diagnosis.
7) Vince and Chao will following the DAQ problem of the strategy in reading scaler.
In order to clean the ring buffer which is filled up quickly, the DAQ will have to read then clean it
frequently such that there is always buffer to fill new signals. However, the scaler is now coupled with
ring buffer therefore each time the ring buffer is read, the scaler (much larger data stream in size) will
also be read. This make the DAQ slow. The solution is to decouple scaler with ring buffer and also read
scaler not so frequently. Once per second might be good enough.
- Min:
1) Tuning the quadrapole in SNAKE. After tuning, the central ray still have 2 mm shift in Q1 aperture.
This shift might be acceptable. Min also need to consider the change in acceptance during tuning
2) Preparing the solid angle acceptance for Karl using the commissioning data.
- Jixie:
1) Need to check the optics run plan again to determine if we need straight through beam for all beam energies
all run plan should be ready by Feb 3rd.
2) Need to check with Ed if we need to operate the sieve by our own
3) Preparing for the target field mapping need TOSP
4) Study the central ray angle for the septum field map again. Found that the center ray is 2.902+/-0.001 GeV/c
and the angle is 5.65+/-0.004 degree. (The old result is 2.956 GeV and 5.69 degree.)
5) Preparing for septum mapping. Need to cooperate with Jack. The 1st measurement shows that there is a 20%
deviation from the tosca model. The data also proof the real field is lower than tosca. Robin already found some
bugs in the tosca. Need to communicate with her and try to get this problem solved.
1/11/2012: Present: Jixie, Min, Kalyan, Pengjia, Toby, Ryan, Melissa, Jie, JP, Karl, Vince, Alex
- Karl, JP:
1) Discuss if we need straight through beam for each energy. (optics needs this setting)
2) 4-channeled BPM was told to be ready in one week
- Toby:
1) Doing lumi analysis, might need to put lumi into the ring buffer is one want to know the
beam asymmetry
- Chao, Kalyan:
1) Setup 3rd arm DAQ to support buffer mode
2) Working on the remote control for the discriminator
3) working on decide the helicity in HAPPEX DAQ
4) Show plots from the septum measurement
- Jixie:
1) Present simulation results for answering questions of the safety review
- Jie:
1) working on the remote control for ROCs
- Melissa:
1) Looking at the multiple tracks events in the commissioning data
- Pengjia:
1) Do we need to turn on the helicity prediction on-line? How much will it slow the DAQ?
Pengjia will study the affect then discuss again.
2) Fitting the BPM1 and BPM2 positions to predict the beam position at the target. Not finished yet.
- Min:
1) Show her analysis for the commissioning optics data and the septum measurement results
- Ryan, Vince:
1) Removing 2 TDC from roc5, reduce teh busy time from 90 to 60 us.
2) Found that the DAQ has defects in strategy to control reading the scaler data, which make it slow.
In order to clean the ring buffer which is filled up quickly, the DAQ will have to read then clean it
frequently such that there is always buffer to fill new signals. However, the scaler is now coupled with
ring buffer therefore each time the ring buffer is read, the scaler (much larger data stream in size) will
also be read. This make the DAQ slow. The solution is to decouple scaler with ring buffer and also read
scaler not so frequently.
1/4/2012: Present: Jixie, Min, Kalyan, Pengjia, Toby, Ryan, Melissa, Jie, JP, Karl, Vince, Alex, Aiden
- Karl, JP:
1) Readiness review will be taken place in Jan 17. All documents are expected to put to this
location by next Tuesday: http://hallaweb.jlab.org/experiment/g2p/meetings/safety_011712/
2) Need new ESAD,COO,RSAD,etc for this review
3) Discuss the charge asymmetry issue. Finally agree to let hall c to control the feed back.
We will dedicate someone to watch it closely. Charge asymmetry should also be monitored for each
run by the 3rd person.
- Kalyan, Chao:
1) Working on remote control to 3rd arm discriminators
2) Will prepare document for 3rd arm
3) Karl suggested to consider the secure the HV cable for safety reasons
4) Chao show the helicity stutus. He has compared the helicity from the trigger to scaler, they
agree with each other. Need to work on the decoding the helicity from HAPPEX DAQ then made another
comparison.
- Jixie, Min:
1) Measured the target foil position. Also talked to survey group and figured it out already.
2) Updating the geant4 simulation with commissioning configuration.
3) Analyzing the optics data.
4) Will talked to John and learn how to tune quadrapoles again dipole.
5) Septum block might have some orientation, or the HRS angle is not correct. Ed has requested
a new survey for them.
- Alex, Pengjia:
1) Working on BCM|BPM. Analyzing the linearity.
- Jie:
1) Working on the remote control to IOC.
- Ryan:
1) Shown his analysis of the HRS deadtime.
- Toby:
1) Analyzing the lumi data. Two channels (#4,#8) did not response.
- Melissa:
1) Finished up efficiency check for CC, EC. Both > 99%.
- Aiden:
1) A new graduate student from MIT will come in about Jan 16. Need to find some project for him.
