SciFi Results and Comparison Malcolm Ellis, for the MICE Scintillating Fibre Group Abingdon, 31

st

October 2003

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The SciFi Group

Japan K. Yoshimura

KEK

Y. Kuno, H. Sakamoto, A. Sato, M. Yoshida,

Osaka

UK P. Kyberd

Brunel

A. Khan, L. Tong

Edinburgh

G. Barber, M. Ellis, K. Georgiou, R. Goncalo, K. Long, J. Sedgbeer, A. Tapper

Imperial College London

P. Cooke, R. Gamet

Liverpool

US A. Bross, J. Estrada, J. Krider, R. Rucinski, P. Rubinov

FNAL

D. Kaplan, Y. Torun

Illinois Institute of Technology

G. Hanson, A. Klier

Riverside

X. Yang

UCLA

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The Tracker

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The Tracker Document



Tracker Document asked specific questions, some common to both detectors, others specific to the individual types.



I will first show the various things that have been done in the past few months to allow us to say Yes, and then list those few items we have not answered so far.

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Simulation



All software in G4MICE environment

 

Simulation of nominal configuration (0.25% dead channels, 7-1 grouping, 1 GHz RF background, etc…) Position, momentum, x’, y’, t’ resolutions determined



No degradation in resolutions for 100x nominal background rate.

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Position Resolution

•X Resolution: 570 microns •Y Resolution: 430 microns 6

Momentum Resolution

•P T Resolution: 1.3 MeV/c •P L Resolution: 5.8 MeV/c 7

X’ Y’ and T’

• X’ Resolution: 7.7 mrad •Y’ Resolution: 4.9 mrad •T’ Resolution: 6.7 x 10 -3 8

Pattern Recognition Efficiency

   

Number of space points in fitted track (or zero if no track fitted) Most of the time 5 space points are made and fitted in track With no dead channels or background: 99.9 ± 0.1 % Overall tracking efficiency in nominal situation: 99.0 ± 0.5 %

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Future Improvements



Track fit still needs correct treatment of Energy Loss in Kalman package – this will be added soon



Track fit currently uses space points, made from intersection of three views in a station. We can add individual fibres as measurements, and thus make full use of all available information



Optimise grouping so as to maintain channel count, but increase point resolution at last station (for example).

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RF Test



201 MHz RF transmitted in close proximity to the VLPC cryostat.



Transmitting antenna operated horizontally and vertically



Received power measured on scope and compared to Lab G test with the same antenna.

•

Pedestal width increased by 0.5 ADC (0.033 PE)

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SciFi Properties



Clear fibre attenuation length measured: 7.62m

22mm  

Light Yield measured for various scintillator types, pT + 5000 ppm has highest yield at 2.6 PE per MIP, measured with a PMT



Systematic effect to be understood, however no cross-talk was observed in any of the scintillating fibres.

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Tracker Prototype Construction



Doublets (ribbons, planes, a single view) constructed at Fermilab



Waveguides built and tested at KEK/Osaka



Carbon Fibre Supports (IC/Liverpool)



Planes aligned and glued to carbon fibre supports



Fibres bundled into groups of 7



Bundles threaded into connector blocks



Bundles potted, cut and polished



Final assembly and test at Fermilab

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Cosmic Ray Data Taking



Two 36x36 cm 2 scintillators in coincidence form trigger.



Lead sheet used for a momentum filter



VLPC timing, pedestal and gains calibrated prior to waveguide connection



Light yield measured



Proper efficiency, dead channels, tracking to come soon…

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VLPC Gain

1p.e.

pedestal 2p.e.

Typical Gain: 15 ADC counts/ p.e.

Preamp Gain Setting: 0x350 Gain Setting: 0x150 6 ADC counts/ p.e.

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Chose events with hits in Upper and Lower Stations

> 10 counts to select cosmic-ray X view V view Station A X view W view Station C 16

Light Yield in Station B

W view V view X view

Peak at 24 counts  4 p.e.

Mean is 4.6 p.e.

X view: PT+3HF 5000ppm W view: PT+3HF 3500ppm V view: PT+3HF 2500ppm Expectation from beam test in KEK • 2.6 p.e. in 0.35mm scifi • QE of VLPC ~ 4 times larger than PMT • Transport loss in waveguide ~ 40% • assume connection loss ~ 10% at each optical connector  •This has a large uncertainty due to PMT calibration 5p.e.

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Expectation based on D0

  

From measurements with 835 micron fibre and 11.5 m waveguide – expect

–

10-12 pe in the current MICE prototype configuration Why the discrepancy?

–

Construction process

•

Aluminisation, ribbon, bundling, connectorising, cutting, polishing, etc.

–

DAQ

•

Gate timing Under investigation Check DAQ timing

–

Independent measurement of fibre light yield

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Single Plane Efficiency



Tracking not reliable yet, so calculate lower bound on efficiency



Require clear hit in the V and W projections of station B

 

Count hits above threshold in third (middle) station Efficiency



95% - consistent with expectations from light yield and threshold setting

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Dead Channels



Cosmic Data rate low, only 7000 triggers, however in these, there are on average 1.29 channels per plane which never have the highest hit in the plane in an event.



This gives an upper estimate for the dead channel rate of 0.6%



Note that as with the efficiency, this number has a large uncertainty. We will improve this with tracking.

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Construction Schedule and Cost



Prototype was completed pretty much to schedule and budget.



Assume we will build 3 trackers, to allow contingency for R&D, spares.

 

First Iteration schedule has delivery on time in 2006 if we start “now”.

Full cost, $1.9M – possible saving of $975k through loan of D0 spares



Excellent opportunity for collaboration with D0, but can’t delay decision long.

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What were the “No” Answers

 

Noise on the mains (filterable)

–

D0 has experience of such noise in the calorimetry electronics but not in the Fibre Tracker.

–

Paul has said we may be able to do this at RAL Didn’t measure performance with known sources (this is known, so perhaps lower priority)



G4MICE has not yet provided emittance reconstruction

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Achievements



7 planes (in 3 stations) of Scintillating Fibre detector have been successfully constructed and operated at D0.



All simulation and reconstruction software is committed to G4MICE and can be used to check fine details of remaining question marks (P T resolution, etc…)

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Future



Open Issues:

–

Understanding Light Yield

–

Resolution in reconstructed parameters and thus emittance



We plan to produce a document by the end of the year addressing all aspects (including the open issues)

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