REM Counters

Option

REM/N and REM/ION counters can be supplied in a number of variants. Feet can be supplied on the side and/or end, and a carry handle can be fitted at a point designed to balance the counter alone or the counter plus electronic package. Performance parameters can be varied by supply of different sensing tubes. The mechanical interface to other equipment can be adjusted to order, and a number of standard connectors fitted.

Spherical REM counters can also be supplied with similar variants; carrying handle, mechanical interface, electrical connector, etc.

Bonner Spheres are very application-specific, and all requirements will be made to order. The design of these products will be discussed and agreed before start of manufacture. 

Any other required options on these products can be considered and such enquiries should be directed, initially, to the sales department.

REM/N

This is one of the earlier REM counter designs still in regular production. It is a cylindrical assembly having a traditional (tubular) counter at it’s centre. This results in a uniform response in all directions at right angles to the counter axis. Typically, these devices have feet which enable them to be stood with the axis either vertical or horizontal, and a handle for portability. The neutron counter generally employed is of the BF₃ filled type.

REM/ION

Whilst very similar to the REM/N, the REM/ION counter utilises an ion chamber in place of the BF₃ counter as a sensing element. Use of the ion chamber enables this type of REM counter to be used in situations where the neutron dose equivalent rate is too high for use of the standard REM/N, or if the pulse repetition frequency is too low. However, it must be noted that the ion chamber is sensitive to gamma radiation as well as to neutrons. This product is not in common use.

Spherical REM (See Also, Bonner Spheres)

Spherical REM Counters use a spherical ³He neutron counter set at the centre of a spherical moderator. This produces a near-isotropic response to neutrons, though there is a ‘dead-spot’ at the counter connector assembly point. Attachment of electronics, etc. will also modify the response in some directions. An optional flat machined on the sphere provides a base on which the counter can stand.

³He has the advantage of being much safer and less reactive than BF₃ gas, particularly for health-related applications. In addition, because ³He is non-electronegative, electrons aren’t captured in the gas, resulting in faster rise times and larger pulse heights—a significant performance benefit.

This product is also smaller and lighter than the REM/N, making it especially well-suited for portable applications.
 

Description

Exosens REM Counters are designed to measure neutron dose equivalent (REM) accurately, providing insight into radiation levels that mimic the biological effects on human tissue. Each counter features a spherical ³He gas detector enclosed in a polyethylene moderator, sometimes augmented with heavy metal inserts like cadmium or lead to enhance response at specific energies.

The spherical design ensures isotropic sensitivity, while the moderator is engineered to approximate energy-independent neutron detection across the range of interest, typically 0.025 eV to 10 MeV. With the appropriate electronic package, the counters provide direct dose readings in rem or sieverts.

REM Counters are suitable for both portable neutron monitoring and fixed installations, offering flexible deployment in health physics, radiation protection, and cosmic radiation studies. Mounting facilities allow integration with compact electronic packages for self-contained monitoring solutions.

These counters combine precision, reliability, and ease of use, making Exosens REM Counters a trusted solution for professionals seeking accurate neutron dose measurements in a variety of environments.