Note that one important circumstance is that in the described nuclear reactor on thermal neutrons the nuclei of natural uranium [sub.92][sup.238]U, capturing fast neutrons
from fission of uranium isotope nuclei [sub.92][sup.238]U or neutrons in the process of their deceleration, do not test their division.
Prompt neutrons are born at energy ranges from 0.1 to 10 MeV but the fast neutron
spectrum component is shifted to lower energies due to the elastic and inelastic scattering interactions of fast neutrons
with sodium as well as structural and other materials existing in SFR.
Since then, diamond detectors have been explored for use in extreme environments [7-11], microdosimetry [12, 13], and thermal [10, 14, 15] and fast neutron
sensing [10, 16-20], including deuterium-deuterium (DD) and deuterium-tritium (DT) fusion plasma diagnostics [21, 22].
In the past, this reaction was discussed in some detail for the detection of fast neutrons
 where a Teflon cup covering a 30 cc Ge(Li) diode was used to detect the 6.13 MeV photon.
To shield from fast neutrons
from the reactor we plan to use additional external layer of water 50 cm thick and on the outside-plastic scintillator as an active veto shield from ionizing particles of cosmic rays penetrating to the depth of about 16 m of water equivalent.
In the typical reactor, fast neutron
are slowed down by moderators to increase the probability of collision between these slow neutrons and the fissile 235U nucleus, and thus increase the amount of energy generated by fission.
These reactors work with fast neutrons
. To produce such fast neutrons
we allow a fast moving proton obtained through an accelerator with energy 1GeV to hit the as a target.
Fermi had discovered that probability of capture was increased if fast neutrons
were slowed down by collisions with a non-absorber or moderator.
Davie employs everyday analogies to explain relatively complex physical problems, my favourite being the use of a pool table to describe the interaction of fast neutrons
with [H.sup.+] ions and soil particles in the explanation of how a neutron probe works.
To minimize potential backgrounds to experiments, single-crystal bismuth filters may be placed in the beam to attenuate gamma rays and fast neutrons
from upstream components in the guide.
Hirsch argued that the tokamak geometry and the need to shield the superconducting magnets from fast neutrons
made DT tokamak power plants too large and expensive compared to fission plants of the same power output.
The probe incorporates a 50 mCi (1.85 GBq) Americium-Beryllium ([sup.241]Am-Be) source, with a source strength of 111000 fast neutrons
per second, and a helium ([sup.3]He) proportional counter detector, some 13.2 cm in length and 2.54 cm in diameter.