Status of the Longitudinal and Transverse Polarimeters
description
Transcript of Status of the Longitudinal and Transverse Polarimeters
![Page 1: Status of the Longitudinal and Transverse Polarimeters](https://reader035.fdocuments.in/reader035/viewer/2022062322/56814c46550346895db94a02/html5/thumbnails/1.jpg)
Baudrand Sylvestre
Physics Research Commitee 1
Status of the Longitudinal and Status of the Longitudinal and Transverse PolarimetersTransverse Polarimeters
•Working polarimeters
•HERA polarization status 2005
•Efficiency of the polarimeters
•TPOL & LPOL
•Cavity LPOL
•Energy spectrum with locked or unlocked cavity
•Bremsstralung spectra
•Present Status
•New calorimeter
![Page 2: Status of the Longitudinal and Transverse Polarimeters](https://reader035.fdocuments.in/reader035/viewer/2022062322/56814c46550346895db94a02/html5/thumbnails/2.jpg)
Baudrand Sylvestre
Physics Research Commitee 2
WORKING POLARIMETERSWORKING POLARIMETERS
![Page 3: Status of the Longitudinal and Transverse Polarimeters](https://reader035.fdocuments.in/reader035/viewer/2022062322/56814c46550346895db94a02/html5/thumbnails/3.jpg)
Baudrand Sylvestre
Physics Research Commitee 3
Polarization Delivered in 2005Polarization Delivered in 2005
•Polarisation is rather low (less than 30%) compared to the previous year.
•Polarization do not show a clear tendency.
•Polarization level is not enough for experiments. For ex.HERMES predictions are based on 50%.
Experiments wait that the Polarization level increase
Helicity change
![Page 4: Status of the Longitudinal and Transverse Polarimeters](https://reader035.fdocuments.in/reader035/viewer/2022062322/56814c46550346895db94a02/html5/thumbnails/4.jpg)
Baudrand Sylvestre
Physics Research Commitee 4
Efficiency of the PolarimetersEfficiency of the Polarimeters
TPOL ~94% LPOL ~91% Both ~98.25%
• LPOL: Machine studies (begin of 2005) + Time for syst. studies and Cavity studies
• TPOL: TPOL vacuum window + Hardware electronics.
![Page 5: Status of the Longitudinal and Transverse Polarimeters](https://reader035.fdocuments.in/reader035/viewer/2022062322/56814c46550346895db94a02/html5/thumbnails/5.jpg)
Baudrand Sylvestre
Physics Research Commitee 5
LPOL & TPOLLPOL & TPOL
![Page 6: Status of the Longitudinal and Transverse Polarimeters](https://reader035.fdocuments.in/reader035/viewer/2022062322/56814c46550346895db94a02/html5/thumbnails/6.jpg)
Baudrand Sylvestre
Physics Research Commitee 6
LPOLLPOL
Good agrement TPOL-LPOL even at online level
2% errors between CR and SW. Detailed systematic studies are planned to decrease this number.
Data from 1st Jan to 20th May show a clear agreement at online level (no LPOL data quality corrections)
CR=Crystal calo. SW= Sandwich calo.
![Page 7: Status of the Longitudinal and Transverse Polarimeters](https://reader035.fdocuments.in/reader035/viewer/2022062322/56814c46550346895db94a02/html5/thumbnails/7.jpg)
Baudrand Sylvestre
Physics Research Commitee 7
TPOLTPOL
Detailed syst. Studies shows beam spot to Polarization correlations.
Monte Carlo simulation confirmed the observation.
Focus correction now applied online to data:
There were some changes in 2005 in hardware:
•Stepping motor controler changed.
•Si detector damaged 2 month ago- Debugging in progress.
•Function generator for depol.
Current TPOL syst. 3.5%
Applied on line
![Page 8: Status of the Longitudinal and Transverse Polarimeters](https://reader035.fdocuments.in/reader035/viewer/2022062322/56814c46550346895db94a02/html5/thumbnails/8.jpg)
Baudrand Sylvestre
Physics Research Commitee 8
NEW CAVITY LPOLNEW CAVITY LPOL
![Page 9: Status of the Longitudinal and Transverse Polarimeters](https://reader035.fdocuments.in/reader035/viewer/2022062322/56814c46550346895db94a02/html5/thumbnails/9.jpg)
Baudrand Sylvestre
Physics Research Commitee 9
The new Cavity LPOL is recording Comptons event now
•Histograms show a clear signal of compton photons above the Bremsstrahlung spectrum.
•Estimation gives a rate of 0.1 photons per bunch crossing
Energy spectrum with locked or Energy spectrum with locked or unlocked cavityunlocked cavity
10/03/05
![Page 10: Status of the Longitudinal and Transverse Polarimeters](https://reader035.fdocuments.in/reader035/viewer/2022062322/56814c46550346895db94a02/html5/thumbnails/10.jpg)
Baudrand Sylvestre
Physics Research Commitee 10
BremsBremssstratrahhlung Spectralung Spectra
• Synchrotron radiation shift has been reduced by putting a one X0 tungsten plate in front of the calo
• Problems with electronics readout induced a « shoulder », now removed
Brems Spectra is now understood
Ibunch =83,7A
PM Voltage: 850V
PM Voltage: 850V
Ibunch=170A
« shoulder »
![Page 11: Status of the Longitudinal and Transverse Polarimeters](https://reader035.fdocuments.in/reader035/viewer/2022062322/56814c46550346895db94a02/html5/thumbnails/11.jpg)
Baudrand Sylvestre
Physics Research Commitee 11
Present statusPresent status
• Locking STABLE under any accelerator conditions.
• Locking STABLE / switch laser pol.
• DAQ problems, under study
• Polarisation estimation almost there.
Cavity LPOL is on the way to deliver polarisation
06/05/05 BREMS
COMPTONS
![Page 12: Status of the Longitudinal and Transverse Polarimeters](https://reader035.fdocuments.in/reader035/viewer/2022062322/56814c46550346895db94a02/html5/thumbnails/12.jpg)
Baudrand Sylvestre
Physics Research Commitee 12
New CalorimeterNew Calorimeter
•Neither of the 2 LPOL calo are suitable for cavity operations.
•Tungsten- Quartz fiber sampling calorimeter.
•Signal produced from Č radiation in the quartz fiber.
•50 layers of tungsten plate interleaved with layers of quartz fiber
![Page 13: Status of the Longitudinal and Transverse Polarimeters](https://reader035.fdocuments.in/reader035/viewer/2022062322/56814c46550346895db94a02/html5/thumbnails/13.jpg)
Baudrand Sylvestre
Physics Research Commitee 13
New CalorimeterNew Calorimeter
Will be finished by end of June, take into operation as soon as possible
•Design and complete simulation of Č light done
•Energy resolution within the requirements
•To do: Cut the fibers & bundle them.
![Page 14: Status of the Longitudinal and Transverse Polarimeters](https://reader035.fdocuments.in/reader035/viewer/2022062322/56814c46550346895db94a02/html5/thumbnails/14.jpg)
Baudrand Sylvestre
Physics Research Commitee 14
ConclusionsConclusions•Working polarimeters:
•In 2005 Efficiency for the LPOL is ~ 91% and TPOL ~ 94%, combined 98.3%
•TPOL & LPOL:
•Polarimeters in agreement within systematics
•Cavity LPOL:
•Procedure for Laser/e-beam interaction now established
•Brems. spectrum is understood. DAQ problems are under studies.
•New calorimeter will be built by the end of June and put in operation immediately after.