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Cherenkov Water Detector

#0643


Cherenkov water Detector of Extensive Air Showers Generated by High-energy Particles

Tech Area / Field

  • SAT-AST/Astronomy/Space, Aircraft and Surface Transportation
  • PHY-PFA/Particles, Fields and Accelerator Physics/Physics

Status
8 Project completed

Registration date
10.05.1996

Completion date
11.01.1999

Senior Project Manager
Malakhov Yu I

Leading Institute
MIFI, Russia, Moscow

Supporting institutes

  • Scientific Engineering Center SNIIP, Russia, Moscow

Collaborators

  • CNRS/ Université de Paris VI ET VII / Laboratorie de Physique Nucléaire et de Hautes Energies, France, Paris\nUniversity of Chicago, USA, IL, Chicago\nUniversita Degli Studi di Torino / Instituto di Fisica, Italy, Torino

Project summary

Experimental arrangements for the detection of extensive air showers (EAS) generated by cosmic ray particles in the atmosphere arc widely used to study primary cosmic ray energy spectrum and super-high-energy particle interaction characteristics, and also to solve g-ray astronomy problems. The most widespread technique of EAS detection on the Earth's surface is based on the registration of various air shower components by a system of scintillation counters. All currently operating setups have two essential demerits:

1. Sensitive elements (scintillation counters) cover only small part of the total area of the arrangement. Non-uniformity of the sensitive area of the detectors does not allow to study in detail the lateral distribution of the energy carried by shower particles.

2. The sizes of the detectors of muon and hadron components arc considerably (tens and hundreds times) less than the area of electron-photon component detector, which makes difficult the separation of showers induced by hadrons and photons, and, consequently, the utilization of such arrangements for g-ray astronomy purposes.

The use of large area Cherenkov water detectors for EAS investigations, suggested by Prof. A.A.Petrukhin, represents a new direction in the development of cosmic ray detection techniques. Water detectors of air showers are free of the above demerits. The working volume of the detectors of this kind is continuous. The continuity of the sensitive volume provides the possibility of model-independent study of the lateral distribution of energy flow in EAS, and simultaneously allows to reduce substantially the energy threshold of primary cosmic ray particle detection. The important feature of these arrangements is nearly equal size of muon, hadron, and electron-photon detectors, which gives the possibility to increase considerably the efficiency of g-induced EAS separation among the background of hadron-initiated showers.

However, the creation of water detectors of air showers is related with various technical, methodical, and physical problems which have to be solved before the design and construction of large-scale arrangements.

The objective of the suggested project is the development of the techniques and methods of the detection of air showers in large water volumes. The unique feature of the project in comparison with the existing experimental setups is the technique of shower particle detection, which is based on the observation of Cherenkov radiation produced by charged particles in water. In the project realization the following problems will be solved:

1) specialized measuring modules capable of detecting Cherenkov radiation in water in a wide dynamic range at depth up to 50 meters will be developed;

2) the techniques of water transparency monitoring and the technology of the detector water volume purification from light-absorbing impurities, thus providing the possibility of low-intensive Cherenkov light fluxes detection will be elaborated;

3) angular, spatial and energy characteristics of the flux of Cherenkov light from air showers in water will be studied;

4) will be determined the optimal conditions for the detection of basic components of air showers in water detectors will be determined.

The project will be realized on the basis of the detector NEVOD which is now under operation in MEPhI. Modernization of a number of electronic and technical systems of the setup will allow to create the unique Cherenkov water detector of air showers with effective area not less than 200 m2 which will be used for the conduction of physical, methodical, technical and technological investigations which are necessary for designing of larger scale arrangements: for calibration of the water tanks - basic modules for the international Auger Project, for investigations of the reliability of EAS muon separation in the American shallow depth water detector (MILAGRO). The measuring part of the detector which is being realized as a complete unified module, may be used as a basis for detecting elements in the MILAGRO setup. In the case the Russian made PMT will be approved for the use in the Auger Project implementation, the technical facilities of the NEVOD complex will be used for test and selection of photo-multipliers for the latter project. Collaboration with MILAGRO and Auger Project scientific groups is confirmed by the supporting letters.

The important feature of the experimental complex to be created will be a wide dynamic range of the detected events, from single muons to high energy air showers, and also the presence of peripheral detectors of different kinds. In particular, the complex includes a large-aperture muon hodoscope with a high spatial, angular and time resolution, which will allow to the permanent monitoring of upper layers of atmosphere, and to search for the sources of their perturbation (earthquakes, powerful explosions, other natural and artificial reasons). It creates the pre-requisites of the use of the experimental complex for applied purposes.


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