1M. Ellis - NFMCC - 31st January 2007 MICE Tracker.

1M. Ellis - NFMCC - 31st January 2007

MICE Tracker


Outline

Tracker design 5 Station tracker 3 planes of scintillating fibre Readout with VLPCs

Prototypes

Quality Assurance

Tracker construction Fibre Mirroring Doublet plane fabrication Waveguides VLPC Cassette Cryostats


A “Station” Carbon Fibre Support

A MICE Tracker

Tracker is in a 4T Solenoid


Fibre Plane

Active Area

Radius > 15cm

426 m

• 350 m scintillating fibres are arranged in two overlapping rows to form a sheet of fibre.

•Active area has a diameter of 30 cm.

•Small fibre minimises radiation length in direction of muon passage.


Readout

Position resolution required is of order 1mm, so no need to read out every single fibre.

Gang 7 neighbouring fibres together into one channel and the light is read out over clear fibre by Visible Light Photon Counters (VLPCs).


VLPCs

Visible Light Photon Counters – operate at 9 Kelvin. Combine high QE with low noise and high rate capability. D0 expertise is gradually being transferred to MICE. Readout through AFEIIt boards (D0 upgrade) firmware

modified for MICE (see T. Hart’s talk).


Prototypes

Several prototype trackers have been built to test the design and construction techniques.

First 3 station tracker was completed in October 2003 and tested in cosmic rays at Fermilab in 2003 and 2004.

An additional station was built to refined specifications with new connectors and tested in a beam (in a 1T solenoid) at KEK in October 2005.

Analysis of the data is ongoing, but an issue with the precision drilling of holes for the fibres was discovered and a 5th station is currently being completed and will be tested as proof of the final design, construction and quality assurance techniques before the final trackers for MICE are built.


Tests at FNAL and KEK


Towards the Final Trackers

Preliminary results from analysis of the KEK data show lower light yield from the 4th station than expected.

This has been traced back to an issue with the CNC drilling of the holes in the connectors.

Construction and testing of the 5th station should verify that this is now solved.

In addition, several tools and techniques have been developed to assist the people when building the tracking planes, in particular:

When bundling 7 fibres into a channel (detect and correct accidental swaps of fibre from one channel into another or incorrect number of fibres in a bundle).

When threading bundles into the station connectors, test to ensure that the channels have been inserted into the correct position.


QA for Bundling and Connectorisation

Ensure each bundle has correct 7 fibres

Ensure correctmapping fromplane to connector


QA Software

CCD images are analysed by software (Imperial College)

The software notifies the operator if there is any failure or suspicious bundles.


Fibre Mirroring and Ribbons

All scintillating fibres have been mirrored.

A small fraction may need to be re-done.

Average reflectivity of the mirror is 75% (RMS 4%).

Ribbon production is well underway with over 28 complete (most of which are now in London).

Frequency

0

50

100

150

200

250

0.6

0.62

50.

650.

675

0.7

0.72

50.

750.

775

0.8

0.82

50.

850.

875

0.9

0.92

5M

ore

Frequency


Waveguides

Waveguides are currently being assembled in Japan.

Have had some issues with the fibre size and holes in the connectors.

Revised procedure has been devised to reduce risk of damage.

Test cookie for fiber QA

D0 connector Bulkhead connectors Station connectors

Internal Waveguide Test cookie

External Waveguide


Cryostats

A prototype two cassette cryostat has been built and operated successfully in the US and Japan.

Most of the parts for the four production cryostats have arrived and they are being assembled at Fermilab.

During this week the first production cryostat is being tested at Fermilab.

All four should be tested and ready to be delivered to RAL in the spring.

Prototype cryostat with one VLPC cassette will go to London to be used to readout the stations that are being assembled for the final trackers as part of the quality control process.


Station Production Status

Station 6: View X

+ bundling/QA+ connectorisation

View W+ bundling/QA-- Connectorisation

ETA: five stations – end of March


Coming months should see:

Complete analysis of KEK data Commissioning of first MICE production cryostats. Completion of system for characterising all VLPC

cassettes used in MICE. Preparation of a readout system based on the

prototype cryostat to be used to readout Station 5 in a cosmic ray test and later used with a radioactive source for testing of all final stations.

Progress on MICE firmware for the AFEIIt boards. Completion of waveguides. Construction and testing of MICE tracker stations.

1M. Ellis - NFMCC - 31st January 2007 MICE Tracker.

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Transcript of 1M. Ellis - NFMCC - 31st January 2007 MICE Tracker.