Quarknet Presentation 20023

1
Quarknet Presentation 2002-3

• By
• Yasar Onel
• University of Iowa
• Iowa City, IA 52242

2
CMS Detector Subsystems
3
CMS in the Collision Hall
Tracker ECAL HCAL Magnet Muon
4
360 tones per side at 8.6 meter1800 electronics
channels5x105 quartz fibers (1000km)Most
radiation-hard calorimeter1 Grad of radiation
field near beampipe
5
CMS Longitudinal View
6
Why HF?

• Covers the pseudorapidity range 3-5
• HF psedorapidity range 4.5-5 will get
  100Mrad/year. Therefore the detector should be
  able to withstand this exceptionally high
  radiation field.
• Two main objectives
• To improve the measurement of the missing
  transverse energy EmissT
• To enable identification and reconstruction of
  very forward jets

7
Experimental Technique

• Light is generated by Cherenkov effect in quartz
  fibers
• Sensitive to relativistic charged particles
  (Compton electrons...)
• d2N/dxdl2paz2(sin2q/l2)
• (2paz2/ l2 )1-1/b2n2
• bmin 1/n
• Emin 200 keV
• Amount of collected light depends on the angle
  between the particle path and the fiber axis

8
HF Collaborators

• Hungary
• KFKI- RMKI - Budapest
• ATOMKI - Debrecen
• Russia
• ITEP- Moscow
• Moscow State U.
• VNIITF (Snezhinsk)
• Turkey
• Cukurova University - Adana
• Middle East Technical University - Ankara
• Bogazici University - Istanbul
• USA
• Boston University
• Fairfield University
• University of Iowa
• Iowa State University
• Texas Tech University

9
Quartz Calorimeter Features

• The detector is intrinsically radiation hard at
  the required level (hundreds of MRads)
• The detector, for all practical purposes, is
  sensitive to the electromagnetic shower
  components (?M)
• It is based on Cherenkov radiation and is
  extremely fast (
• Low but sufficient light yield (
• The effects of induced radioactivity and neutron
  flux to a great extend are eliminated from the
  signal
• Neutron production is considerably reduced
  (high-Z vs low-Z)
• The detector is relatively short
• The detector is perfectly hermetic

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Iowa-Fairfield-ORNL
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CMS_HF Prototype
Measured energy resolution for electrons (upper
figure) and pions (lower figure) for the HF
calorimeter. In the hadronic energy study, the
intrinsic resolution is found to scale with the
logarithm of the energy (squares in the lower
figure).
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HF Fiber Spacing (PPP1)
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HF Fiber Spacing

• 0.6 mm quartz fibers in iron
• Half a million quartz fibers viewed with about
  2000 phototubes

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CMS-HF PPP1
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CMS-HF PPP1
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HF PPP1 Side View
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Response to Electrons and Pions

• HF PPP1 responds linearly within 1 to electrons
  in the energy range tested (6 200 GeV). The
  pion (neg) response is highly nonlinear.

18
Electromagnetic Energy Resolution
137/sqrt(E) with 1.6 fiber packing Fraction
(HAD95)

• Electromagnetic energy resolution is completely
  dominated by photostatistics (Np.e.). The usual
  parametrization, a/sqrt(E) b, results in a192
  and b9 for the PPP1. 0.85 fiber fraction
  degrades the EM energy resolution by a sqrt(2)
  compared to HAD95 (1.6).

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Hadronic Energy Resolution

• Hadronic energy resolution is dominated by
  non-stochastic processes at higher energies.
  Photo statistics becomes important only at lower
  energies. The intrinsic energy resolution can be
  expressed as c-dln(E). The expected energy
  resolution at 1 TeV is 18.

20
Previous Experimental Data on Photodetectors by
HF Group
R6427
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Uniformity Scan with Electrons

• There is a /- 6 response nonuniformity to
  electrons due to fiber periodicity at every 2.5
  mm (5 mm for EM).

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Summary PPP1

• 1 linearity in response to electrons. Highly
  non-linear to negative pions
• Electromagnetic Energy Resolution 192 ? 9
• Expected Hadronic Energy Resolution at 1TeV is
  18
• /- 6 non-uniformity in response to electrons
  due to fiber periodicity
• Suppressed induced radiation damage on fibers
• in PMT region (400-500nm)

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HF - Mechanics Wedge Concept
PMT Plate
Ferrule Plate
Strong Back
Air-core Light Guides
20-degree Steel Wedge
Borated (Pb) Polyethylene
Fibers Source Tubes

• The concept wedge allows for a simpler
  construction scenario. Each 20-degree sector is
  optically and electrically independent. This
  makes manufacturing, quality control and testing
  more streamlined.

24
HF Wedge and Optical Assembly

• HF 20-degree sectors will be assembled into a
  superstructure with the aid of two L-shaped
  lifting fixtures. Each sector is optically and
  electronically independent.

The routing of the fibers and source tubes are
designed and being tested on the PPPWedge this
month (February 2001).
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HF READOUT BOX OPTICS DESIGN
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Optics Fiber Routing and Termination
Fibers
Source Tubes
Wedge
Ferrules

• Preliminary fiber insertion studies have been
  carried out with the PPP2 wedge.

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HF - EDIA, FNAL - RDMS
0.5 cm spacing, packing fraction, source tubes,
edge chamfer design complete.We have started to
produce wedges.
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HF - Optical Routing
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HF Responsibilities
Mechanics Design (US)
Cylindrical Shielding (CERN)
Optical Assem. (HU)
FE, Trig/DAQ DCS, Voltage (US)
Fibers - QP (US)
Strongback, Ferrule Plate (Turkey)
Luminosity (US)
Calibration (US)
Absorber (RDMS)
Photodetectors (US)
Transporter (IRAN)
Readout Boxes (US)

• End Plug
• (CERN)

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Mechanics Wedge Assembly Scenario

• Mechanical design and the detector assembly
  scenarios are carried out at Fermilab. The
  support structure houses a half of the HF
  detector in a rigid frame. Around it, there is a
  matrix of shielding elements made out of steel,
  concrete and polyethylene (not shown).
• The transporter table is being designed. It
  allows for opening of the detector in half and
  also allows for motion in the beam direction.

Shielding
Support Structure
20-degree wedge
Transporter (not shown)
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First 2 HF Wedges in Superstructure

• The wedges will be bolted onto the superstructure
  for support and it also serves as a part of the
  steel shielding.

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½ HF in Superstructure
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Assembled HF

• The HF will rest on a transporter table that
  enables motion to clear the beam pipe during
  installation and maintenance.

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Iowa Raddam 98 Module
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IOWA LIL-CERN Radiation Damage Facility
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IOWA LIL-CERN Radiation Damage Facility
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Fiber Radiation Damage and Induced Resolution
54 Mrad QP

• Quartz fiber irradiation studies have been
  carried out in the last several years. The
  induced attenuation profile shows that there is
  less absorbtion in 400-500 nm (PMT) region
  compared to either shorter or longer wavelengths.

38
HF Fiber
QP (Quartz, Plastic) Fused silica core, polymer
cladding, UV-cured acrylate buffer. 850 km for
600 core N.A. 0.33 /- 0.02

• QQ (Quartz, Quartz)
• Fused silica core, fluorine-doped silicate
  cladding, polyimide buffer.
• 100 km for 600 core
• N.A. 0.22 /- 0.02

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HF Design Parameters Update

• The HF fiber matrix is optimized for the required
  performance and ease of optical assembly. Two
  independent simulation studies indicate that the
  fiber spacing can be coarsened without much
  degradation in performance.
• Fiber Spacing
• 5 mm x 5 mm square grid (from 2.5 mm x 2.5 mm)
• Quartz fiber packing fraction
• 0.85 ( 600-micron core dia.)
• Fiber OD 800-micron dia.
• The fiber hole/groove max OD 900-micron
• Dead region between wedges
• 5 mm or less between fibers of neighbor wedges
• No change in
• h x f segmentation (0.175 x 0.175)
• 165 cm (EM), 143 cm (HAD)
• Diffusion welded grooved steel plates

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HF Transverse Segmentation
3 EM (24/20-deg) HAD (24/20-deg) TOTAL(48/20-deg)
The active region extends from r12.5 cm to 130
cm. The depth is 165 cm (Fe).
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XY Uniformity
XY Uniformity, Dark Current, Relative Gain
8 channel pico-ammeter
Pinhole Mask
32 channel Voltage ADC
Motor Controller
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Iowa PMT Timing Test Setup
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Iowa Light Guide Test Setup
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Iowa Light Guide Test Setup
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X Uniformity without light guide
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Uniformity with Al mylar light guide
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Uniformity with HEM (straight) light guide
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Light guide with 375 GeV pion
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Light Guide with 80 GeV e-
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Higgs Search
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HCAL - ? Coverage
(A.Nikitenko)
HF needed for tag jets, missing ET and jet vetoes
(SUSY)
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Higgs Discovery Reach
The WW fusion process, isolated by 2 tag jets
with formation of the Higgs and subsequent decay
into W W may be THE discovery mode for Higgs
masses 53
Summary

• HF is now part of the working detector. The
  Physics of SUSY requires HF at first beam.
• The gantry crane will lower HF into UX5 in 2004.
• The CMS-HCAL community/leadership has created a
  plan to meet this critical path milestone. We
  have begun the HF constructions.

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Assembled Strongback-Wedge