Speaker
Mr
Egor Pinzhenin
(Budker INP SB RAS)
Description
Gas dynamic trap facility (GDT) is axisymmetric magnetic mirror trap for fusion plasma confinement [1]. There are fusion reactions in GDT during deuterium injection:
D + D -> He3 (0.82 MeV) + n (2.45 MeV)
D + D -> T (1.01 MeV) + p (3.02 MeV)
Thus registration of fusion reaction products is important contactless plasma diagnostics. This diagnostics contains information about fast particle distribution function, influence microinstabilities and collective effects to fast particles in GDT facility. Moreover it is direct simulation of neutron flux distribution for support theoretical and numerical research of GDT based neutron source.
As well as proton and neutron registration is used in GDT research [2]. Registration of neutrons in magnetic confinement facilities contains such advantages as: no influence of magnetic and electric fields, you may mount your detector out of vacuum vessel, but it is difficult to collimate thus it is difficult to obtain high spatial resolution. Neutron detectors based on PMT and plastic scintillator are used for timing measurements of DD reaction yield. On the other hand 3.02 MeV protons may be collimate easily, and you can obtain enough spatial resolution of your diagnostics. Detectors based on photodiode are used for 3.02 MeV proton registration. It works in counting mode, it is insensitive to magnetic field and neutron background of GDT experiment condition. Thus additional flux calibration do not require. Fusion proton diagnostics are used for absolute measurements with spatial resolution few cm.
Multichannel system of fusion proton registration in the GDT with high spatial (tenth of cm) and timing ($\sim$100 mks) resolution is developed by authors of the report. System for radial distribution of 3.02 MeV proton emissions is based on set of photodiode. Sensors are placed near the mirror point. System for longitude distribution is based on set of photodiode placed along the GDT device (detectors work in counting mode). Results will be presented in the report.
Gas dynamic trap facility generates $2\times 10^9$ neutrons per 5 ms. The DD product yield was measured 2 $10^9$cm$^{-1}$s$^{-1}$ near the mirror point. Neutron flux was $3\times 10^{11}$ $s^{-1}$ (in the same place). There is linear growth of neutron flux during experimental shot according to data of timing distribution of neutron flux detector so there is no steady-state plasma confinement regime in the GDT device.
[1] Bagryansky, et al. FUSION SCIENCE AND TECHNOLOGY, Vol. 59, No. 1T, p. 31-35 (2011).
[2] Bagryansky, et al. FUSION SCIENCE AND TECHNOLOGY, Vol. 59, No. 1T, p. 256-258 (2011).
Primary author
Mr
Egor Pinzhenin
(Budker INP SB RAS)
Co-author
Vladimir Maximov
(Budker INP SB RAS)
