status of the fets laserwire scanner david lee uknfic meeting 07.11.08 [email protected]
TRANSCRIPT
David Lee • 07/11/2008
Outline
Introduction
Vacuum Vessel
Optics
Detector
> Field Map
> Electronics
Conclusion / Outlook
Status of the FETS Laserwire Scanner • 1
David Lee • 07/11/2008
The Front End Test Stand
Magnetic LEBT
RFQ
MEBT and chopper
H− ion source
Laser profile monitor
Status of the FETS Laserwire Scanner • 2
David Lee • 07/11/2008
The Front End Test Stand
Magnetic LEBT
RFQ
MEBT and chopper
H− ion source
Laser profile monitor
Status of the FETS Laserwire Scanner • 2
David Lee • 07/11/2008
Photo-dissociate some of the H- ions
Separate species using a dipole magnet
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Laser-based Beam Diagnostics: Principle for H−
Collect the detached electrons
Status of the FETS Laserwire Scanner • 3
David Lee • 07/11/2008
Photo-dissociate some of the H- ions
Separate species using a dipole magnet
−
−−
−
−
−
− −
−−−
−
−
−−
−
−
−
−
−
−
−−
Collect the detached electrons
−−
−
−
−
−
−
Laser-based Beam Diagnostics: Principle for H−
Status of the FETS Laserwire Scanner • 3
David Lee • 07/11/2008
Photo-dissociate some of the H- ions
Separate species using a dipole magnet
−
−−
−
−
−
− −
−−−
−
−
−−
−
−
−
−
−
−
−−
Collect the detached electrons
−−
−
−
−
−
−
Laser-based Beam Diagnostics: Principle for H−
Status of the FETS Laserwire Scanner • 3
David Lee • 07/11/2008
Photo-dissociate some of the H- ions
Separate species using a dipole magnet
−
−−
−
−
−
− −
−−−
−
−
−−
−
−
−
−
−
−
−−
Collect the detached electrons
−−
−
−
−
−
−
Laser-based Beam Diagnostics: Principle for H−
Status of the FETS Laserwire Scanner • 3
David Lee • 07/11/2008
Photo-dissociate some of the H- ions
Separate species using a dipole magnet
−
−−
−
−
−
− −
−−−
−
−
−−
−
−
−
−
−
−
−−
Collect the detached electrons
−−
−
−
−
−
−
Laser-based Beam Diagnostics: Principle for H−
Status of the FETS Laserwire Scanner • 3
David Lee • 07/11/2008
Photo-dissociate some of the H- ions
Separate species using a dipole magnet
−
−−
−
−
−
− −
−−−
−
−
−−
−
−
−
−
−
−
−−
Collect the detached electrons
−−
−
−
−
−
−
Laser-based Beam Diagnostics: Principle for H−
Status of the FETS Laserwire Scanner • 3
David Lee • 07/11/2008
Steering the Laser Beam
Status of the FETS Laserwire Scanner • 4
David Lee • 07/11/2008
Steering the Laser Beam
Status of the FETS Laserwire Scanner • 4
David Lee • 07/11/2008
Vacuum Vessel Internals Installation
Status of the FETS Laserwire Scanner • 5
David Lee • 07/11/2008
Optics
Optical table constructed in R8
Simple optics design compete
Gives reasonable performance in terms of laser diameter in the interaction region
Reconstruction of overlapping measurements could overcome problems with laser performance
Status of the FETS Laserwire Scanner • 6
David Lee • 07/11/2008
Vessel / Optics: To Do
One of the plates from the tank internals needs modifying
In the workshop today
Re-installed next Wednesday
Vacuum window to couple in the laser to be constructed
Have some drawings showing how this could be done
Complete laser safety requirements for RAL
Interlocks / Screening
Documentation
Install laser and optics at RAL
Alignment…
Status of the FETS Laserwire Scanner • 7
David Lee • 07/11/2008
The Electron Detector (I)
H−, H0
Electrons
Electroncollector
Magnet
Copperaccelerating
sheath
Status of the FETS Laserwire Scanner • 8
David Lee • 07/11/2008
The Electron Detector (II)
Status of the FETS Laserwire Scanner • 9
David Lee • 07/11/2008
Detector Magnet Field Map (I)
Status of the FETS Laserwire Scanner • 10
David Lee • 07/11/2008
Detector Magnet Field Map (II)
Status of the FETS Laserwire Scanner • 11
Magnet measured in opposite polarity to how it’s will be used &how it’s previously been tested
Discrepancy due to hysteresis
David Lee • 07/11/2008
Detector Readout
“Prototype” “Production”
Status of the FETS Laserwire Scanner • 12
David Lee • 07/11/2008
Detector: To Do
Test ‘production’ electronics
Finish installation of detector
Magnet
Readout
Power / data feed-thoughs
Status of the FETS Laserwire Scanner • 13
David Lee • 07/11/2008
Reconstruction Software
Test figure
No overlap 50 % (?) overlap
Test figure
Status of the FETS Laserwire Scanner • 14
David Lee • 07/11/2008
Conclusions and Outlook
The FETS laserwire scanner is progressing (reasonably) well
Installation should be complete by the end of the month
Then *all* we need is a beam
And then the fun really begins…
Status of the FETS Laserwire Scanner • 15
Backup Slides
David Lee • 07/11/2008
H− Injection
H− from Linac
Circulating protons
Stripping foil
Status of the FETS Laserwire Scanner • 16
David Lee • 07/11/2008
The Need for Multiple (>2) Projections
Status of the FETS Laserwire Scanner • 17
David Lee • 07/11/2008
The Need for Multiple (>2) Projections
Status of the FETS Laserwire Scanner • 17
David Lee • 07/11/2008
The Need for Multiple (>2) Projections
Status of the FETS Laserwire Scanner • 17
David Lee • 07/11/2008
The Need for Multiple (>2) Projections
Status of the FETS Laserwire Scanner • 17
David Lee • 07/11/2008
Laser-based beam diagnostics principle for H−
Photo-dissociate some of the H- ions
Separate species using a dipole magnet
−
−−
−
−
−
− −
−−−
−
−
−−
−
−
−
−
−
−
−−
Collect the detached electrons
−−
−
−
−
−
−
Rev. S
ci. Instrum
. 73
, 998
(20
02)
Status of the FETS Laserwire Scanner •18
David Lee • 07/11/2008
ADC
Two channel, integrate and hold, 20-bit ADC
Minimum sensitivity: −0.2–50 pC
Expected signal size ~1 pC so in effect we have a ~ 14-bit ADC
Status of the FETS Laserwire Scanner • 19
David Lee • 07/11/2008
ADC Protoboard
DDC112
Clock In
Atmel
μprocessor
RS232 to PC
Input 1
Power inRangeselectjumpers
Status of the FETS Laserwire Scanner • 20
David Lee • 07/11/2008
ADC Test Charge Resolution
Status of the FETS Laserwire Scanner • 21
David Lee • 07/11/2008
The Need for Non-Destructive, Non-Interceptive Diagnostics
Allows for online monitoring of the beam
Status of the FETS Laserwire Scanner • 22
David Lee • 07/11/2008
The Need for Non-Destructive, Non-Interceptive Diagnostics
Allows for online monitoring of the beam
Prevents the beam damaging the instrument
Plastic RubyP46
Status of the FETS Laserwire Scanner • 22