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Cherenkov Quartz Calorimeter

#0728


Cherenkov Quartz Calorimeter

Tech Area / Field

  • INS-DET/Detection Devices/Instrumentation

Status
8 Project completed

Registration date
27.08.1996

Completion date
30.11.2000

Senior Project Manager
Malakhov Yu I

Leading Institute
ITEF (ITEP), Russia, Moscow

Supporting institutes

  • VNIITF, Russia, Chelyabinsk reg., Snezhinsk

Collaborators

  • EURATOM-Ciemat, Spain, Madrid\nCERN, Switzerland, Geneva

Project summary

The goal of this project is development of the technology for production of the calorimeters based on the quartz fibers, which will be produced for CMS detector at CERN (Geneva, Switzerland). CMS will be one of two general-purpose detectors at the Large Hadron Collider, which will be built at CERN. Calorimeters will be used for very small angles (from 0.5 ° to б °) with respect to axis of the interacted proton beams. Extremely high particle fluxes and energies should be detected and as the result high radiation fields are expected in this angular range. Radiation doses are expected to be up to 100 Mrad per year and neutron fluxes should be up to 109 n/cm2 s. The calorimeter should allow hermetic energy fluxes registration in this region and should operate reliably during 10 years.

The calorimeter based on Cherenkov effect in optical quartz fibers is one of few detector types, which can be used for solving of the problems described above. The calorimeter consists of optical quartz fibers embedded into absorber matrix made of copper or iron alloys. Cherenkov light emitted by relativistic charged particles yielded in the processes of the shower production in the absorber by high energy particles is captured partially and transferred by fibers to photodetectors (PMT) which are installed outside the region of high radiation fields. So the calorimeter has only one active component (quartz fibers) in the region of high radiation doses. The quartz fibers have sufficient radiation hardness to provide the guaranty of reliable operation for the calorimeter.

In addition to high radiation hardness the calorimeter based on the quartz fibers for region of small angles at CMS detector will have a set of very important features:


1) Very fast signal (shorter than 10 ns) which allow to detect reliably the signals from particles produced in different bunch interactions, which will have a period of 25 ns between interaction.
2) Very low sensitivity to neutrons and products of their interaction and also with respect to products of radioactivation.
3) Narrow spatial region in which the signal will be formed (more than two times narrower than for conventional calorimeters based on ionization or scintillation caused by secondary particles).

The problem of the technology development for the industrial production of the components for very forward calorimeters for CMS is under consideration now. One of the important stages of this technology will be manufacturing of the absorber of total weight of 150-200 t. providing the high radiation and mechanical requirements. It can minimize the calorimeter cost.

The scientists and engineers of ITEP and VNIITF interacting closely with the industry will develop the technology of the absorber plates production with the precise grooves for the quartz fibers and provide the assembling of the plates into the packages with a weight of several tones.

A lot of secondary neutrons will be produced in the very forward calorimeter of CMS. So the shielding will be a very important component which will reduce the neutron flux to the required level.

One of the tasks of this project is the development of physical and mathematical model for mapping the radiation field in calorimeter, shielding and other components of detector CMS. This model will help to optimize the composition and the construction of the shielding in terms of efficiency, weight, sizes and cost.

48 scientists and engineers from Russian nuclear weapon industry will participate in this project and will spend 429 man-month to fulfill the project. The activities on this project are planned in collaboration with foreign institutes. The joint studies carried out by groups of scientists from Russia, USA and Western Europe allowed to explore the main characteristics of the Cherenkov quartz fiber calorimeter prototypes and to determine the optimal parameters for very forward calorimeters of CMS(1-4)

The goal of this project is a development of the industrial technology for calorimeter manufacturing with the participation of the scientists and engineers from Russian military industry. The effective in terms of cost and quality solution should be found to build the experimental setup, which will satisfy the requirements.

Scientists and engineers from military plants involved into collaboration will get a good knowledge concerning international standards of design and production. The developed technology can be used in other branches where the equipment, which can operate in high radiation fields, is needed.

Expected results

The physical and mathematical model of the calculation the radiation fields and doses in the detector and experimental hall will be developed as the result of the project completion. Optimization of the geometry and the materials of shielding will be performed, the documentation concerning the technology of the production and the assembling of the absorber and shielding will be prepared. The industrial prototype of the calorimeter module will be produced.

The role of foreign collaborators

The University of Iowa (USA): Joint definition of the requirements to quality of the quartz fibers, joint studying of the quartz fibers radiation hardness, development of optical surface processing and optical properties test for quartz fiber bundles. Joint test of the module.

CIEMAT (Spain): Joint simulation of the calorimeter characteristics and radiation fields. Joint test of the calorimeter module.

CERN (Swiss): Joint definition of the requirements to the calorimeter shielding, definition of the requirements to the calorimeter plates. Joint test of the calorimeter module.

Bibliography


1). G.Anzivino et al., "Recent Development in Quartz Fibers Calorimetry", NTN, A357, 369-379, 1995
2). G.Anzivino et al., "Angular Dependence of Quartz Fiber Calorimeter Response", NIM, A360, 237-239, 1995
3). G.Anzivino et al., "Quartz Fiber Calorimetry-Monte Carlo Simulation", NIM, A357, 380-385, 1995
4). N.Akchurin et al., "Quartz Fiber Calorimeter" - The proceedings of VI International Conference on "Instrumentation for experiments at e+ e- colliders", submitted to NIM.


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