neutron radiation sources

Research nuclear reactors

The neutron radiation sources with suitable examples and sketches are discuss here advanced. Neutron radiation sources is needed to read.

Types of neutron sources:

  1. Isotopic (ampoule) sources.
  2. The accelerator as a source of neutrons.
  3. Neutron generators.
  4. Reactors:
  5. industrial research: – continuous; – impulse.
  6. Plasma traps.

Research nuclear reactors

The first nuclear reactor was created under the direction of E. Fermi in 1942 in Chicago. The first beam research reactor (HFBR) was created in 1965 in Brookhaven. Today, there are several dozen research reactors in the world. The characteristics of the reactors, some of which have already been decommissioned, are reflected in Table.

ReactorPower, MWFlow × 10^14, neutr. cm-2s-1
PIK, Gatchina, Russia 10045
HFIR, Oak Ridge, USA 10030
HFR-ILL, Grenoble, France5815
HFBR, Brookhaven, USA 609
FRM-2, Munich, Germany 208
NRU, Chok- River, Canada 1253
ORPHEE, Saclay, France 142.5
JRR-3M, Ibaraki, Japan 202
Dhruva, Bombay, India 1002
IR-8, Moscow, Russia 81
BER-II, Berlin, Germany 101
The characteristics of the reactors

To use the time-of-flight technique, circuit breakers are installed on stationary reactors. Using two choppers, it is possible to form a monochromatic neutron beam. The first chopper serves to produce a pulsed beam. The second, installed at some distance from the first – for its monochromatization. Higher-energy neutrons reach the second chopper faster than lower-energy neutrons. By choosing the rotation speed of the choppers accordingly, it is possible to achieve a situation where the second chopper will pass neutrons only in a certain energy range. At the PIK (PNPI) reactor, a mechanical monochromator consists of four modules of the same type, which are placed along a collimated neutron beam. Each module represents

a rotor made of durable steel alloy. The energy resolution of the device depends on the speed of rotation of the rotors and the energy of the transmitted neutrons. In particular, at a speed of 15,000 rpm and a neutron energy of E ≈ 1 eV, to which the monochromator is tuned, ΔE / E ≈ 0.05. Nuclear reactors with a continuous neutron flux have flow limitations associated mainly with the problem of cooling. In pulsed reactors at the same average power, the yield of neutrons used for research is many times higher. Recently, the number of research reactors has been decreasing, and the future of intense neutron sources is associated with the use of accelerators.

The neutron radiation sources with suitable examples and sketches are discuss here advanced. Neutron radiation sources is needed to read.

Reference neutron radiation sources

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