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
CMS-UK Oversight Committee 18/11/03 D.J.A. Cockerill - RAL 16
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