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MICE Video MTG9/25/2002
MICE Fiber Tracker Design Update
Requirements and Proposed Detector Implementations
A. BrossFermilab
MICE Video MTG9/25/2002
Detector Options
Letter of Intent based the trackers on four planes of scintillating fiber
MICE Video MTG9/25/2002
Fiber Tracker Option for MICE
At this point we have taken a VERY conservative approach to the Fiber Tracker
Assume Backgrounds are extremely high! Requires use of smallest fiber diameter possible
– 350 micron– Under these assumptions, the Fiber option may be the
only one that will work uvt readout station
Doublet structure 0.3 % Xo per station
5 stations/spectrometer This yields a system with about 45k channels!
VLPC readout <3 m light piping fibers from detector to VLPC
MAJOR EFFORT And COST $5M
Of course, other assumptions can reduce the cost/effort significantly!
MICE Video MTG9/25/2002
Fiber Tracker Channel
MirrorScintillating
Fiber
Optical connector
Waveguide
VLPC cassette
Electronics
Cryostat
MICE Video MTG9/25/2002
Scintillating Fiber Ribbons
Interlocking doublet 835 m 3HF scintillating fiber
Fluorescence 525 nm (peak) to 610 nm
Grooved substrate - machined Delrin
Pitch between 915 and 990 m Optimal P/d 1.2
Substrate put into curved backbone Fibers glued together with
polyurethane adhesive Ribbons is then QC’ed using
scanning X-ray source Technique is very fast
All MICE planes require 4 MMeffort + Tooling
MICE Video MTG9/25/2002
VLPC Readout Option
VLPC (Visible Light Photon Counter)
Cryogenic APD operating @ 9K
Characterization/test/sort Cassette Assignment
As shown
MICE Video MTG9/25/2002
1024 Channel VLPC Cassettes
Engineering Design 8 – 128 channel modules Cassette carries two 512 ch
readout boards Front-end amp/discriminator Analog – SVX IIe
3’
MICE Video MTG9/25/2002
Lab 3 CRT (Singlet) Light Yield
Lab 3 CRT Light Yield Summary Covers Waveguide lengths 7.7-11.4m
MICE Video MTG9/25/2002
MICE Fiber Tracker
Conventional FT using MAPMT
With same length of readout fiber
If waveguides are used 430 nm = 1300 dB/km (1/e =
3.4m) 525nm = 450 dB/km (1/e =
9.6m)– D0 measured 8.1m @ f
p = 525 nm
QE = 20% Yield =
9 X 20/80 X exp(-5/3.4)/exp(-5/8)
1 pe Waveguide length would have to
be limited to 2 to 3 meters
Attenuation vs. wavelengthof Kuraray clear fiber
3 HF
Conventional Blue
MICE Video MTG9/25/2002
On-Going Work
We have prototyped ribbons 500 and 350 micron diameter Will measure light yield with VLPCs at Fermilab
Trying to put together small test system (128 ch) for use at KEK test beam in Dec.
Negotiated with Fermilab management for support Most parts exist, however need to assemble new
cassette 128 ch VLPC cassette based on D0 parts Cryo system exists
– Commercial Oxford flow cryostat Can measure
Light yield Resolution Timing performance
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