ALCPG Tracking Session 1/11/03 K. Riles - U. Michigan1 Status Report on Michigan Group Tracker...
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Transcript of ALCPG Tracking Session 1/11/03 K. Riles - U. Michigan1 Status Report on Michigan Group Tracker...
ALCPG Tracking Session 1/11/03
K. Riles - U. Michigan 1
Status Report on Michigan Group Tracker Alignment R&D
Keith Riles, Jin Yamamoto, Haijun Yang
University of Michigan
ALCPG Tracking Group Session
January 11, 2003
ALCPG Tracking Session 1/11/03
K. Riles - U. Michigan 2
.
Why?
Assumption:
Inner detector subject to thermal drifts on time scales too short to collect adequate control sample of tracks for determining alignment from data
Conclusion:Need independent alignment system with rapid tracking of drifts “Real time alignment”
Goal:
Carry out R&D toward a low-mass, real-time tracker alignment system with O(1 micron) precision
ALCPG Tracking Session 1/11/03
K. Riles - U. Michigan 3
Two optical alignment schemes used in present / future experiments:
•RASNIK system -- L3 CHORUS CDF
•Frequency Scanned Interferometer (FSI) – ATLAS
[A.F.~Fox-Murphy et al., Nuc. Inst. Meth. A383, 229 (1996)]
Focusing efforts here on FSI approach
Seems more promising for low-material tracker
Basic idea:
Measure hundreds of absolute point-to-point distances on tracker structure, using an interferometer “fanout” of optical fibers from a central laser.
Laser frequency is scanned and fringes counted for each channel to determine absolute distances. Infer tracker distortions from fit.
ALCPG Tracking Session 1/11/03
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Status:
•Requested funds in joint UCLC/LCRD proposal – waiting…
•Former graduate student (Jin Yamamoto) has been spending part-time laying groundwork for acquiring equipment
•Big-ticket item – Scannable laser
•First choice: New Focus “Velocity” series (~630 nm) Tuning range: >3.5 THz (nominal f = 480 THz)
•Cost: ~$20K
•Infrared (~1.5 μm) laser with comparable range available for ~$10K – fallback option but visible light preferable
ALCPG Tracking Session 1/11/03
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Other components planned for first bench test:
•Photodiode
•Corner reflector
•Optical fibers and couplers
•Etalons (reference cavities)
Conceptual design:
•Need straw man configuration of interferometer beams
•Need simulation infrastructure for optimizing design
•Seeking talented student to write simulation program
ALCPG Tracking Session 1/11/03
K. Riles - U. Michigan 6
Summary
Poised to order laser (and wavelength-dependent components) – awaiting signal of funding likelihood:
In parallel will develop simulation tools to optimize design
Would love to know funding situation better…