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