Neutrons cannot be detected by the same detectors as alphas, betas, or gammas. Why? Briefly describe some methods for detecting neutrons. Solution Neutrons are high-speed nuclear particles that have an exceptional ability to penetrate other materials. Of the various types of ionizing radiations, neutrons are the only one that can make objects radioactive. Because of their exceptional ability to penetrate other materials, neutrons can travel great distances in air and require very thick hydrogen-containing materials (such as concrete or water) to block them Neutrons are much harder to detect because they are not charged. Other detectors like Geiger Muller Counter, Scintillation Detectors make use of charged particle. Neutrons are thus detected by nuclear interactions that produce secondary charged particles. For example, boron trifluoride (BF3) counters make use of the10B(n,a)7Li reaction to detect neutrons. Often one uses a moderator, such as paraffin, to slow the neutrons and thus increase the detection efficiency. These detectors are used to monitor the neutron fluxes in the vicinity of a reactor or accelerator. Neutron REM Meter, with Proportional Counter—A boron trifluoride or helium-3 proportional counter tube is a gas-filled device that, when a high voltage is applied, creates an electrical pulse when a neutron radiation interacts with the gas in the tube. The absorption of a neutron in the nucleus of boron-10 or helium-3 causes the prompt emission of a helium-4 nucleus or proton respectively. These charged particles can then cause ionization in the gas, which is collected as an electrical pulse, similar to the GM tube. These neutron- measuring proportional counters require large amounts of hydrogenous material around them to slow the neutron to thermal energies. Other surrounding filters allow an appropriate number of neutrons to be detected and thus provide a flat-energy response with respect to dose equivalent. The design and characteristics of these devices are such that the amount of secondary charge collected is proportional to the degree of primary ions produced by the radiation..

1. Neutrons cannot be detected by the same detectors as alphas, betas, or gammas. Why? Briefly
describe some methods for detecting neutrons.
Solution
Neutrons are high-speed nuclear particles that have an exceptional ability to penetrate other
materials. Of the various types of ionizing radiations, neutrons are the only one that can make
objects radioactive. Because of their exceptional ability to penetrate other materials, neutrons can
travel great distances in air and require very thick hydrogen-containing materials (such as
concrete or water) to block them Neutrons are much harder to detect because they are not
charged. Other detectors like Geiger Muller Counter, Scintillation Detectors make use of charged
particle. Neutrons are thus detected by nuclear interactions that produce secondary charged
particles. For example, boron trifluoride (BF3) counters make use of the10B(n,a)7Li reaction to
detect neutrons. Often one uses a moderator, such as paraffin, to slow the neutrons and thus
increase the detection efficiency. These detectors are used to monitor the neutron fluxes in the
vicinity of a reactor or accelerator. Neutron REM Meter, with Proportional Counter—A boron
trifluoride or helium-3 proportional counter tube is a gas-filled device that, when a high voltage
is applied, creates an electrical pulse when a neutron radiation interacts with the gas in the tube.
The absorption of a neutron in the nucleus of boron-10 or helium-3 causes the prompt emission
of a helium-4 nucleus or proton respectively. These charged particles can then cause ionization
in the gas, which is collected as an electrical pulse, similar to the GM tube. These neutron-
measuring proportional counters require large amounts of hydrogenous material around them to
slow the neutron to thermal energies. Other surrounding filters allow an appropriate number of
neutrons to be detected and thus provide a flat-energy response with respect to dose equivalent.
The design and characteristics of these devices are such that the amount of secondary charge
collected is proportional to the degree of primary ions produced by the radiation.