6.0.1
Calorimetry
Calorimetry
Calorimetry Table of Contents
Table of Contents and Overview...... 6.0
54. Design and Prototyping of a Scintillator-based Digital Hadron Calorimeter (UCLC; Vishnu Zutshi) 6.1
55. Linear Collider Detector Development Proposal to Develop Scintillator-Fiber Readout Calorimetry with a Novel Geometrical Design that has Excellent Spacial Resolution (LCRD; Uriel Nauenberg) 6.2
56. Fast Response Tile Scintillation Development for Calorimetry and Tracking in NLC Detectors (UCLC; Mike Hildreth) 6.3
57. Energy Flow Studies with the Small Detector at the Linear Collider (LCRD; Usha Mallik) 6.4
58. Development of a silicon-tungsten test module for an electromagnetic calorimeter (LCRD; Raymond Frey) 6.5
59. Digital Hadron Calorimetry for the Linear Collider using GEM based Technology (LCRD; Andy White) 6.6
60. Development of energy-flow algorithms, simulation, and other software for the LC detector (UCLC; Dhiman Chakraborty) 6.9
61. Investigation and Design Optimization of a Compact Sampling Electro-magnetic Calorimeter with High Spatial, Timing and Energy Resolution (UCLC; Graham Wilson) 6.10
62. RPC Studies and Optimization of LC detector elements for physics analysis (UCLC; Mark Oreglia) 6.11
63. Micro-machined Vacuum Photodetectors (LCRD; Yasar Onel)...... 6.12
64. Cherenkov compensated calorimetry (LCRD; Yasar Onel)...... 6.13
65. Study of Resistive Plate Chambers as Active Medium for the HCAL (LCRD; José Repond) 6.14
66. Proposal for Design Study of Active Mask for Future Linear Collider (LCRD; Teruki Kamon) 6.15
6.0.1
Calorimetry
Introduction to Calorimeter R&D
To explore the uncharted territory of the Electroweak symmetry breaking energies,
identification of Z, W and Higgs from their respective reconstructed decays is critical. This requires good lepton identification and very good jet energy resolution so that
reconstructed jet-jet energies can be accurately measured. Dijet mass must be measured to a precision of ~3 GeV or, in terms of jet energy resolution, (E in GeV). [52]
The most important aspect of the calorimeter is to provide accurate measurements of the four-momenta of charged and neutral particles, individually and in jets. In the present parlance of calorimetry, this is best achieved by an Energy Flow algorithm in three dimensions. [53] The Energy Flow (or Particle Flow) Algorithm consists of following the tracks measured by the tracking detector into the calorimeter and measuring their respective energy deposits. These particles, which typically carry ~60% of a jet’s total energy, are measured with much higher precision by the magnetized inner tracker. The electromagnetic calorimeter (ECal) is used to measure EM showers, carrying on average ~25% of jet energy, with a resolution of . This way, even though the energy resolution of the hadron calorimeter (HCal) for single hadrons may be no better than , a net jet energy resolution of is achievable by using the HCal to measure only the neutral hadrons, typically carrying merely ~11% of the total jet energy.
If realized, a detector for the LC will likely be the first with a calorimeter designed specifically for Energy Flow Algorithms. [54] It will be a challenge to develop algorithms under the unique conditions and constraints of the new facility. These will in turn drive the technology and design choices not only for the calorimeter, but for the inner tracker and the muon systems as well. For the calorimeter to be able to track and isolate charged particles in a jet while staying within a realistic budget, some features favored by traditional algorithms of sampling calorimetry may have to be sacrificed to gain 3-D tracking or imaging capabilities in the calorimeter. Particularly for the hadronic calorimeter, collecting a large number of hits with good position resolution will be more important than estimating the amount of energy associated with each hit. The current favorite designs for the NLC and TESLA calorimeters have ~30 layers of ~0.25 cm2cells totaling ~25 radiation lengths in the ECal and ~40 layers of 1-10 cm2cells totaling ~4.8 interaction lengths in the Hcal. [55, 56]
The Energy Flow scheme clearly requires a highly segmented calorimeter, both laterally and longitudinally. In principle, once the energy flow is fully accomplished, the long-coveted similar response to electrons and hadrons, namely, e/h ~ 1, should not be
necessary, since energy deposited by each particle will be measured individually. However, to what extent this can be accomplished needs to be tested both by realistic simulations, and in beam tests.
The considerations of cost and the technological challenge in satisfying the desire of having the entire calorimeter immersed in a 4-5 T magnetic field limit the radius of the calorimeter in the more popular designs. While a finely segmented calorimeter will aid muon measurements, the muon system may be required to serve as a “tail-catcher” for parts of jets leaking through the relatively thin calorimeter.
Several competing technologies have been proposed and are being investigated under a worldwide collaborative effort. [57] Possible alternatives for the ECal include Si-W, Scintillator-W or Scintillator-Pb, and lead tungstate crystals. Plastic scintillators, Resistive Plate Chambers (RPC), and Gas Electron Multipliers (GEM) are all candidates for possible active media for the HCal. Hybrids employing multiple technologies are also possible for both the ECal and the HCal. UCLC and LCRD proposals aim to study these options, with all groups working in close collaboration.
Hardware development must proceed in tandem, and in close cooperation with simulation studies. The design optimization must begin with simulation, while data from test-beam studies of the prototypes will help fine-tune the parameters of the simulation. Development of algorithms and extensive studies of a multitude of physics scenarios are key to designing the detector and charting the physics program. While every group interested in a specific detector technology accepts the responsibility of testing it in simulation, the overall plan involves much more. A flexible yet powerful software environment is required to generate millions of Monte Carlo (MC) events under various scenarios both within and beyond the Standard Model, simulate detector response to those under different options, reconstruct the signatures, tune algorithms, and parametrize detector response for very large volumes of MC events for which full detector simulation is not feasible. Several university groups, including some primarily involved in calorimetry, plan to contribute to the common infrastructure, support, and MC production service for the entire LC community. Increasingly, this effort is converging toward a global unification. Technical and fiscal considerations favor international collaboration in the planning and execution of beam tests as well. [58]
A number of sub-proposals, C, D, and E, shown in the table below, are about various simulation studies, in particular, regarding Energy-Flow and various types of optimizations. Sub-proposal E is presently attempting the simulation of some of
the proposed technology choices prior to developing an EM calorimeter. The second part of C includes developing readout electronics and is also part of sub-proposal L. Proposal P concentrates on detector performance issues associated with recognition of gamma-gamma events, which are expected to comprise a serious background for certain types of SUSY signals.
C. / UCLC6.11 / RPC Studies and Optimization of LC detector elements for physics analysis / Mark Oreglia / University of Chicago
D. / UCLC
6.9 / Development of Energy-Flow Algorithms, Simulation and Other Software for the LC Detector / Dhiman Chakroborty / NICADD
E. / UCLC
6.10 / Investigation and Design Optimization of a Compact Sampling EM Calorimeter with High Spatial, Timing and Energy Resolution / Graham Wilson / University of Kansas
P. / LCRD
6.15 / Proposal for Design Study of Active Mask for Future Linear Collider / Teruki Kamon / Texas A&M
Sub-proposals F and G, shown in the table below, are to study a finely segmented Silicon-Tungsten electromagnetic calorimeter and a longitudinally (in addition to laterally) segmented electromagnetic crystal calorimeter. Both proposals include simulation studies as well.
F. / LCRD6.5 / Development of a silicon-tungsten test module for an electromagnetic calorimeter / Raymond Frey / University of Oregon
G. / LCRD
6.4 / Energy flow studies with the Small Detector at the Linear Collider / Usha Mallik / University of Iowa
Shown below are a number of proposed calorimeters with scintillators and/or detectors of various types, H, I and J. Sub-proposal I specifically mentions HCAL. Two different types of hadron calorimeters are also proposed, sub-proposal K proposes use of GEM-based technology and sub-proposal L proposes use of glass RPC's. As part of the study, simulation is included in H, I and K. Proposal N will investigate the possible use of vacuum photodetectors.
H / LCRD6.2 / Linear Collider Detector Development Proposal to Develop Scintillator-Fiber Readout Calorimetry with a Novel Geometrical Design that has Excellent Spacial Resolution / Uriel Nauenberg / University of Colorado
I. / UCLC
6.1 / Design and Prototyping of a Scintillator-based Digital Hadron Calorimeter / Vishnu Zutshi / NICADD
J. / UCLC
6.3 / Fast Response Tile Scintillation Development for Calorimetry and Tracking in NLC Detectors / Mike Hildreth / Notre Dame
K. / LCRD
6.6 / Digital Hadron Calorimetry for the Linear Collider using GEM based Technology / Andy White / U.Texas at Arlington
L. / LCRD
6.14 / Study of Resistive Plate Chambers as Active Medium for the HCAL / Jose Repond / Argonne National Lab
M. / LCRD
6.13 / Cerenkov Compensated Calorimetry / Yasar Onel / University of Iowa
N / LCRD
6.12 / Micro-machined Vacuum Photodetectors / Yasar Onel / University of Iowa
The sub-proposal M is based on the use of Cerenkov compensated Calorimetry to provide event-by-event compensation by exploiting ionization and the Cerenkov radiation.
References
[52] J. C. Brient, H. Videau, Calorimetry at the future e+e- linear collider, hep-ex/0202004, and references therein, The American Research on LC Calorimetry xorg/lcd/calorimeter/, and a collection of Calorimetry-related talks given at various LC workshops talks.html, The CALICE project and European research on LC Calorimetry html, The Asian Research on LC Calorimetry
[53] P.Gay, Energy Flow with high-granularity calorimeters, LCW 2000, Fermilab, Oct. 2000. Calorimeter%20Clustering.pdf.
[54] Worldwide Calorimeter Activities of the International Linear Collider Detector R&D www-jlc.kek.jp/subg/cal/WWCAL/index.html.
[55] Linear Collider Physics Resource Book for Snowmass 2001, American Linear Collider Working Group, BNL-52627, CLNS 01/1729, FERMILAB-Pub-01/058-E, LBNL-47813, SLAC-R-570, UCRL-ID-143810-DR, LC-REV-2001-074-US, hep-ex/0106058 stanford.edu/snowmass/OrangeBook/index.html.
[56] Physics at an e+e- collider, R. D. Heuer, D. Miller, F. Richard, P. Zerwas, TESLA Technical Design Report, Part III, hep-ph/0106315 PartIII/physic.html.
[57] Reports presented at the Cornell workshop of the ALCPG, July 2003, ˜dhiman/lc-cal/cornell03/cal_agenda.html, LC Calorimetry summary presented at the Cornell workshop of the ALCPG, July 2003, LC/workshop/talks/Chakraborty_calsummary.ppt.
[58]