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03/27/2003
Small angle GDH preparation:
- Jian-Ping:
- septum magnet is currently at 9.4K and still on cooling down slope.
- The critical point is at 9.2K.
- Septum should be operating below 7K.
- The experiment will be an additional week late: beginning after April, 20th.
- Vince:
- measured the field gradient created by the correction coils
- showed the results of the field mapping done in December for Spin Duality
- did a field map with the field clamp in.
- Water calibration done last weekend wasn't successful.
WM lab status:
- Todd:
- first water calibration with a standard cell.
- the signal looks good and now they are trying to improve it.
Spin duality analysis :
- Patricia:
- the right arm shower calibration is done: it was just a problem of the detmap.
- the energy resolution is 6-7% with the preshower+shower counter.
- gave a dry talk for APS meeting.
g2n analysis :(Kevin)
- showed the transverse polarized cross section at 2.581GeV.
- Studied the quasi-elastic peak height versus Q2 --> error is 12%.
- looked at the ratio of GDH fit to Polrad transverse cross section.
03/20/2003
Small angle GDH preparation:
- Alexandre:
- fast feedback will be on all the time.
- did simulation MC of the sieve slits for Nilanga.
- Jian-Ping:
- will leave on Friday 28 for one week.
- Alexandre will be the contact person during Jian-Ping absence.
- Seonho:
- taking care of on-line analysis
- Patricia:
- laser shield will be ready on Monday, so will start alignment then.
- will take care of the DAQ script and EPICS start_of_run and end_of_run
- Vince:
- finished field calibration
- did RF calibration: F(kHz)= 1.471 + 32.46*V
- Showed the results of the field mapping done in December for Spin Duality
- explained his plans about the field mapping for nGDH.
- Jing:
- helped Vince to connect back all target cables
- will help Bob with replugging back the DAQ cables
- will help Patricia with the laser alignment
Cell production:
- Todd:
- all three spheres have good lifetime.
- The cell made at the same time as the 72-hours-lifetime sphere is right now spining down.
Spin duality analysis :
- Patricia:
- contacted Armen about the shower calibration. Seonho thinks that the problem is coming from the detmap.
- replay is done, now improving code to get asymmetries
g2n analysis :(Kevin)
- Compare his calculation with Keith one (did about one year ago)
- NMC fit is pretty bad in the resonance region.
GDH analysis :(Karl)
- comparison of delta sigma para and perp for 862 MeV with Seonho's analysis
--> agree pretty well.
- now checking polarized elastic tail.
03/13/2003
Small angle GDH preparation:
- Alexandre:
- Runplan: optimized on GDH not on each setting.
- For each setting change, the target operator will have to adjust compensating coils.
- Jian-Ping:
- Septum: cool down should be done next wednesday, then start the power up and acceptance test.
- During acceptance, magnetic probe in target system to check the effects.
- field mapping is crucial.
- Bob Mickaels needs help to reconnect the DAQ system due to the clean up.
- Seonho:
- 14 showers blocks to be changed.
- is helping Alexandre with the runplan.
- Nilanga:
- need positions of the sieve slits.
- new pivot location --> new position of the origin.
- need cerenkov calibration coefficient to prepare the database for the experiment.
- Patricia:
- set up all posts at 80cm away from original position.
- On Friday, will start optics alignment:
1) clean up the laser hut.
2) move back all the optics from the target lab.
3) start alignement with pointer.
- Vince:
- will connect the Helmhotz coils.
- field calibration during the weekend
- prepare plan for field mapping: certainly 2 mappings needed --> one with longitudinal coils on and one with tranverse coils one.
Spin duality analysis :
- Patricia:
- preshower-shower calibration: working on it.
- asymmetries: used the wrong ESPACE version on the last replay, so replaying again.
- preparing APS talk.
g2n analysis :(Kevin)
- Elastic and quasi-elastic contributions (unpolarized)
- compare his results with what Karl generated for him: significant difference in the resonance region.
- after quasi-elastic substraction: longitudinal asymmetries are 1 sigma lower and tranverse asymmetries 3 sigma lower.
GDH analysis :(Karl)
- working on polarized elastic tail:
1) used code Rosetail to generate unpolarized elastic tail
2) used Alexandre's code to get elastic asymmetries
3) multiplied unpolarized elastic tail by the asymmetries to get polarized elastic tail.
03/06/2003
Small angle GDH preparation:
- Alex:
- Rad Worker II training will be certainly on Thursday 13.
- we will have 3 target ladders for the experiment.
- For short run settings, don't want to do all 3 target spin configurations.
- won't run above 30% deadtime.
- want to have a quick online analysis for elastic kinematics.
- need to check raising tail during commissionning with ref. cell run.
- water calibration on standard and ice-cone cells necessary before the beginning of the experiment.
- Jian-Ping:
- GDH will run with G0 mode.
- we will perform water calibration as often as we can.
- Seonho will be the shift coordinator.
- run coordinators: 1) Doug, 2) from Haiyan's group, 3) Robert, 4) Xiaodong, 5) Todd's postdoc or Olivier.
- Karl will take care of the correction coils and gradient coils.
- Kevin will be in contact with the EPICS group to integrate the reading of the helmholtz coils currents in the datastream. Also he will setup the spectrum analyser to be control from the counting house.
- Patricia:
- preshower mapping is done: Map, histo --> no bad blocks found.
- Jian-Ping said that laser hut is ready and so Patricia can start the installation of the optics.
- need to order RTDs.
- Jaideep:
- would like to use the A-phi box for the water calibration.
g2n analysis :(Kevin)
- Unpolarized quasi-elastic and elastic cross sections.