MICE Video MTG 9/25/2002 MICE Fiber Tracker Design Update Requirements and Proposed Detector Implementations A. Bross Fermilab

MICE Video MTG 9/25/2002 Detector Options  Letter of Intent based the trackers on four planes of scintillating fiber

MICE Video MTG 9/25/2002 Fiber Tracker Option for MICE u At this point we have taken a VERY conservative approach to the Fiber Tracker u Assume s Backgrounds are extremely high! s Requires use of smallest fiber diameter possible –350 micron –Under these assumptions, the Fiber option may be the only one that will work u uvt readout station s Doublet structure s 0.3 % X o per station u 5 stations/spectrometer u This yields a system with about 45k channels! s VLPC readout s <3 m light piping fibers from detector to VLPC u MAJOR EFFORT And COST s $5M u Of course, other assumptions can reduce the cost/effort significantly!

MICE Video MTG 9/25/2002 Fiber Tracker Channel Mirror Scintillating Fiber Optical connector Waveguide VLPC cassette Electronics Cryostat

MICE Video MTG 9/25/2002 Scintillating Fiber Ribbons  Interlocking doublet  835  m 3HF scintillating fiber u 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 u 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 MM effort + Tooling

MICE Video MTG 9/25/2002 VLPC Readout Option  VLPC (Visible Light Photon Counter) u Cryogenic APD 9K  Characterization/test/sort Cassette Assignment u As shown

MICE Video MTG 9/25/ Channel VLPC Cassettes  Engineering Design u 8 – 128 channel modules u Cassette carries two 512 ch readout boards s Front-end amp/discriminator s Analog – SVX IIe 3’

MICE Video MTG 9/25/2002 Lab 3 CRT (Singlet) Light Yield Lab 3 CRT Light Yield Summary Covers Waveguide lengths m

MICE Video MTG 9/25/2002 MICE Fiber Tracker  Conventional FT using MAPMT  With same length of readout fiber u If waveguides are used   430 nm = 1300 dB/km (1/e = 3.4m)   525  nm = 450 dB/km (1/e = 9.6m) –D0 measured f p = 525 nm u QE = 20% u Yield = s 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. wavelength of Kuraray clear fiber 3 HF Conventional Blue

MICE Video MTG 9/25/2002 On-Going Work  We have prototyped ribbons u 500 and 350 micron diameter u 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. u Negotiated with Fermilab management for support u Most parts exist, however need to assemble new cassette s 128 ch VLPC cassette based on D0 parts s Cryo system exists –Commercial Oxford flow cryostat u Can measure s Light yield s Resolution s Timing performance