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Intensive Neutrino Source

#1431


Calibration and Testing of the Technology for the Preparation of an Intense Neutrino Source Based on AR-37 Isotope as well as for the Calibration of an Iodine Detector of Solar Neutrinos

Tech Area / Field

  • FIR-ISO/Isotopes/Fission Reactors
  • SAT-AST/Astronomy/Space, Aircraft and Surface Transportation

Status
8 Project completed

Registration date
18.12.1998

Completion date
25.11.2005

Senior Project Manager
Alexandrov K A

Leading Institute
Russian Academy of Sciences / Institute of Nuclear Research, Russia, Moscow

Supporting institutes

  • FEI (IPPE), Russia, Kaluga reg., Obninsk\nExperimental Designing Bureau of Machine Building (OKBM), Russia, N. Novgorod reg., N. Novgorod\nBeloyarsk NPP, Russia, Sverdlovsk reg., Zarechny\nInstitute of Reactor Materials, Russia, Sverdlovsk reg., Zarechny

Collaborators

  • University of Pennsylvania / School of Arts and Sciences, USA, PA, Philadelphia\nUniversity of Washington / Institute of Nuclear Theory, USA, WA, Seattle

Project summary

The solar neutrino problem has been and continues to be one of the most important issues of present day nuclear physics and astrophysics and may represent our first excursion into the physics beyond the present Standard Model. The critical result of four existing experiments detecting solar neutrinos - chlorine, SUPERKAMIOKANDE, SAGE and GALLEX - is an essential deficit of electron neutrinos generated in the nuclear fusion reactions that power the Sun's energy emission, essential deficit of electron neutrinos generated in the nuclear fusion reactions that power the Sun's energy emission.

Most strikingly, there is an almost complete absence of electron neutrinos from 7Be in the observed solar neutrino spectrum. A new solar neutrino detector, one that uses 127I as a target and detects electron neutrinos via the reaction 127I(vc,e-)127Xe, has been proposed to more carefully investigate this absence of 7Be neutrinos. Calculations suggest that the 127I detector will have a significantly enhanced sensitivity to 7Be neutrinos. However, a quantitative measurement of the solar neutrino flux is impossible without a specific calibration of the detector with an artificial neutrino source of known intensity. One of the best neutrino source for this is 37Ar. The decay of 37Ar, by orbital electron capture, generates neutrinos of 814 keV, very close to 862 keV - the energy of neutrinos emitted by 7Be decay in the Sun.

The immediate goal of this project is the development of the technology required to produce an unique 57Ar source with an intensity of 1..2 MCi. The only viable present approach to producing such an intense source of 37Ar is by irradiation of a massive calcium target in a high power nuclear reactor with a high flux of fast neutrons, such as BN-600, in Russia. As a response of natural calcium on neutron irradiation the isotopes of argon (mainly 37Ar) and also other gaseous products such as helium and hydrogen are formed. After irradiation the gaseous phase must be extracted from the target by physical or chemical methods. After extraction, the extracted argon must be reliably packed in a minimum volume in order to increase the efficiency of registration of neutrino flux from a source by an iodine detector. The activity of the prototype of a source should be reliably determined, for example, by calorimetric method.

The reactor BN-600 is a power reactor, that is, it's main goal is the production of electric power. Therefore it is necessary for us to clearly demonstrate that the irradiation of a calcium containing target in BN-600 is both safe and within required technological parameters. These considerations then determine the need to carry out a wide range of calculations and experimental tests. So, the main purpose of the project is the development of safe technology for the creation of a compact neutrino source based on 37Ar isotope as well as technology of calibration of an iodine detector of solar neutrinos. The experience gained in the successful completion of this project will also permit the production of high-intensity 37Ar sources for other future experiments. Furthermore, the set of technological solutions and the experience obtained can be applied to the use of fast breeder reactors for the production of other radionuclides useful for medicine, industry, scientific research.

An important overall expected result is the creation of prototype of the source with intensity 250..400 kCi, delivery this source to the Baksan neutrino observatory and the test calibration of single module of the iodine detector. This result should be considered as a test of the developed technology and will verify overall technical readiness for the creation of a full-scale neutrino source and full-scale calibration of the iodine detector.

The project completion will be carried out in close cooperation with INR RAS, which has unique experience in detecting solar neutrino with the gallium-germanium neutrino telescope (GGNT), and with the leading institutes - developers of nuclear technologies. A similar cooperative program was involved in the production of a 0.6 MCi intensity neutrino source in the breeder reactor BN-350 in Kazakhstan that was used to calibrate the GGNT. Also involved in the proposed project is Beloyarskaya NPP, which is experienced in the generation of artificial radioactive isotopes such as 60Co etc. in the reactor BN-600.

Potential Role of Foreign Collaborators

All stages of the project will be completely opened for the participation of any foreign collaborators. The collaboration may be realized in different forms including immediate financial, scientific and engineer participation in all stages of the project completion. A special role of possible foreign collaborators is expected in promotion of the technology obtained to the world market.


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