The accelerator based neutron sources with suitable examples and sketches are discuss here advance. Accelerator based neutron sources is need to read.
Types of neutron sources:
- Isotopic (ampoule) sources.
- The accelerator as a source of neutrons.
- Neutron generators.
- industrial research: – continuous; – impulse.
- Plasma traps.
The accelerator as a source of neutrons.
Of course, the accelerator cannot be considered as a direct source of neutrons. To obtain neutrons, targets are used that are bombarded by accelerated particles. In most cases, reactions of the type (p, n), (d, n), (t, n), and (α, n) are use. At a certain fixed angle to the flux of incident particles, a monoenergetic neutron flux emerges in the energy range from several kiloelectron-volts to 20 MeV. To obtain any specific reaction, a thin target is irradiated with a sufficiently strong stream of monoenergetic particles, and neutrons emerging from the target at a give angle with respect to the direction of motion of the incident particles will have a certain energy. Reactions (p, n) are endoenergic.
As a result of this, when thin targets are bombarded with protons with energies only slightly above the threshold, monoenergetic neutrons with relatively low energies can be obtain. The most commonly used reaction is 7Li (p, n) 7Be, which gives neutrons of intermediate energies and fast 0.5 ÷ 2.0 MeV.
Fast and very fast neutrons are obtain by the reaction (d, n). These reactions, with the exception of 12C (d, n) 13N, are exoenergetic. The dependence of the neutron energy on the emission angle is show in Fig for the reaction 2D (d, n) 3He. The characteristics of some reactions (d, n) used by the neutron production fraction are give in Table.
Characteristics of the reactions (d, n) used to produce neutrons
|Reaction||Q, MeV||En (Ed = 0), MeV|
|2D (d, n) 3He||3.265||2.45|
|3T (d, n) 4He||17.4||14.1|
|7Li (d, n) 8Be||15||13.3|
|12C (d , n) 13N||-0.281||Epo = 0.328|
The same reactions (mainly 3T (d, n) 4He and 2D (d, n) 3He) are use in neutron generators.
Dependence of neutron energy on the angle of departure. Numbers at curves – deuteron energy in megaelectron-volts
The accelerator base neutron sources with suitable examples and sketches are discuss here advance. Accelerator base neutron sources is need to read.