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Hall A Compton Polarimeter For Hall A Collaboration Meeting June 23 rd 2005. Sirish Nanda Thomas Jefferson National Accelerator Facility 12000 Jefferson Ave, Newport News, Virginia 23606. Electron detector. Photon detector. Optical cavity. Dipoles. Hall A Compton Polarimeter. - PowerPoint PPT Presentation
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Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Hall A Compton Polarimeter For Hall A Collaboration Meeting
June 23rd 2005
Hall A Compton Polarimeter For Hall A Collaboration Meeting
June 23rd 2005
Sirish NandaThomas Jefferson National Accelerator Facility
12000 Jefferson Ave,Newport News, Virginia 23606
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Optical cavity
Photon detectorElectron detector
Dipoles
Hall A Compton Polarimeter
15 m
Non-intrusive measurementHigh current capability
- 30 cm deflection chicane- Detection of backscattered photons and recoil electrons
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Operational Status
• SRC Experiment: High current operation Beam quality monitoring Development tests of integrating DAQ.
• Trouble begins… Laser Power supply/controller failed. Backup power supply incompatible Unable to contact manufacturer=> PANIC!
• Solution Manual calibration of new controller. Rework EPICS control algorithm => Problem Solved. We no longer have a spare.
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
SRC Expt
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Counting vs. Integrating
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Lightwave 1064nm Laser
Laser Head
Controller/PS (in intensive care!)
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Cavity Lock @half power
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Compton Upgrade: Scope
• Green Laser and Cavity (30% completed)
Four-fold increase in figure-of-merit Larger scattering angles => possible to detect
electrons at lower energies
• New Electron detector (5% completed)
Finer pitch improves energy resolution Adjustable distance from beam to improve
dynamic range
• Integrating Photon DAQ (70% completed)
Provides redundancy to photon counting Improved systematics
(Cost 250k$)
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Green Optics Test Setup
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Laser Safety Issues
• Jab Safety Standards require a dedicated Green laser room
• Lab management is in the process of get us dedicated lab space in the ARC building
• Until then… We have set up a low power (class II, “e.g laser
pointer”) setup in the EEL Lab We can study most things at low power Get to know the green Laser and cavity Test setup is now operational in EEL
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
EEL Green Optics lab (Temporary)
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Laser: Power Response
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Laser: SHG Temp Response
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Green: Near field Beam spot
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Green Laser: beam profiling
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Green Laser Beam focus
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Turnkey Polarimeter (Thorlabs)
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Prometheus laser’s beam pol
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Polarization after FOI/45
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
…After QWP
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Circular Polarization for cavity injection
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Deepa’s Prototype cavity
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Cavity Mirror Mount
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Beam Injection to Cavity
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Green beam!
Thomas Jefferson National Accelerator Facility
Hall A Collaboration MeetingS. Nanda, June 23, 2005
Conclusion
• The present IR Compton laser/cavity is operating ok. But needs a functional backup laser, just in case…
• The integrating Compton DAQ has made great progress. Needs better understanding of systematic errors
• The Green Compton project is moving well. But needs help.
• It desperately needs a dedicated Green Laser lab.
I hope to complete the Green Compton Project by 2007.