CMS-UK Oversight Committee 18/11/03 D.J.A. Cockerill - RAL 1

The CMS ECAL Endcaps

Crystal ECAL Endcap Calorimeter

(EE)

PreshowerEE

CMS-UK Oversight Committee 18/11/03 D.J.A. Cockerill - RAL 2

CMS ECAL Endcap, EE

UK Involvement

Design and assembly of the EE

The UK has led the EE project since its inception:

- detailed Monte Carlo simulations

- optimisation of the physics performance

- research and development of Vacuum Photo-Triodes (VPTs)

- detailed mechanical design and systems integration

- testing of Supercrystals (SCs) in beams at CERN

The UK is responsible for

- completing the detailed design and systems integration

- procurement and testing of VPTs

- design and procurement of the VPT HV system

- procurement of the mechanical structures for the detector

- assembly of 50% of the SCs

CMS-UK Oversight Committee 18/11/03 D.J.A. Cockerill - RAL 3

Vacuum Photo-triodes (VPTs)

25.4 mm

Testing

1.8T at RAL

4T at Brunel

Production proceeding to schedule4000 devices per annumLast delivery Q4 2005

Concerns: anomalous devices, 6% of production.

CMS-UK Oversight Committee 18/11/03 D.J.A. Cockerill - RAL 4

EE Crystals

EE crystals larger than the barrel crystals

Shallower taper - different light collection

- no depolishing

100 prototype crystals evaluated in 2001

- results fed back to producer

100 pre-production crystals received in 2003

- under evaluation at Imperial and Brunel

Aim to place order for EE crystals by end of this year

Crystals on critical path

CMS-UK Oversight Committee 18/11/03 D.J.A. Cockerill - RAL 5

EE SC mechanics

Design complete

Contract15,000 inserts

600 interface plates 600 housings

Completed by Electro-Mec

(Reading) Ltd in Oct 03.

Interface plate and housing

ConcernsLate EE crystal delivery SC mass production not

before Q4 2005

Inserts

CMS-UK Oversight Committee 18/11/03 D.J.A. Cockerill - RAL 6

EE large mechanics progress

Presampler

Environmental Shield (Russia)

Supercrystals

Positional spacers

Back plate

Ring flange

Moderators (Russia)

HadCal E

Electronics Mechatronics

3.5 m

Design complete forBackplate

Ring flangePositional spacers

Contract signed with TM Engineering, UK

Phase 1 test pieces successfully completed at TM to specification

Nov 2003.

Positionalspacers

Samplebackplate

Dummy SCs

CMS-UK Oversight Committee 18/11/03 D.J.A. Cockerill - RAL 7

EE electronics integration

Remaining major design task

Detailed design for theintegration of electronics

and serviceson the back of EE

Concerns:Complex area

Requires input from other sectors of ECAL

Need to pre-order cable looms etc well before

parallel Dee assembly in 2006

CMS-UK Oversight Committee 18/11/03 D.J.A. Cockerill - RAL 8

EE Calibration at test beam

UK has demonstrated that the design meets the performance

specifications of CMS

Combined crystal plus preshower response to electrons at 180 GeV

Resolution 0.62%

CMS-UK Oversight Committee 18/11/03 D.J.A. Cockerill - RAL 9

EE planning

CMS-UK Oversight Committee 18/11/03 D.J.A. Cockerill - RAL 10

EE planning

Complete EE-1 in Q2 2007

with reduced testing/calibration on

Dee4

CMS-UK Oversight Committee 18/11/03 D.J.A. Cockerill - RAL 11

CMS EE Conclusions

Design for EE system integration and preparation for mass production top priorities.

The mass production of SCs and the assembly of 4 Dees in 2006 will require a smooth transition from ECAL Barrel to ECAL Endcap production.

UK seeking and encouraging other CMS ECAL institutes to participate in the mass production and assembly.

Uncertainty on EE crystal delivery THE major concern

UK successfully undertaking its deliverables to CMS

- VPT procurement, test and appraisal

- SC and large mechanics design and procurement

- HV system design

CMS-UK Oversight Committee 18/11/03 D.J.A. Cockerill - RAL 12

Additional info follows, next slide

CMS-UK Oversight Committee 18/11/03 D.J.A. Cockerill - RAL 13

VPT response in magnetic field

• Characteristic response of VPT– vs angle at B = 1.8T– vs magnetic field at angle of 15– nb: flat response v field above 1T

8-24 in CMS

CMS-UK Oversight Committee 18/11/03 D.J.A. Cockerill - RAL 14

Measured yield in 1.8T field

• Measured yield– In 1.8T field– Mean over 8-24– Converted to

electrons/MeV

• VPTs meet CMS requirements

• Good correlation with measurements at 0T and 4T

CMS-UK Oversight Committee 18/11/03 D.J.A. Cockerill - RAL 15

Measurements in different B fields

• Manufacturers measure p & g at 0T– pg well correlated

with yield at 1.8T

• Sample testing at 4T using Brunel Univ superconducting solenoid– Good correlation

with 1.8T data

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Relative gain at 4T

Production tubes

0

10

20

30

40

50

60

70

0.8 0.85 0.9 0.95 1 1.05 1.1 >1.1

Relative 4T/0T pulsed gain (upper bin edge)

Nu

mb

er

in b

in

Passed