RZ -133 Neutron/Gamma Ray Survey Instrument with Directional Response

Delta Epsilon has developed and patented a unique radiation survey monitor that represents a breakthrough in the high efficiency detection and rapid localization of sources of gamma and neutron emitting radiation. Its principal innovations are twofold: (A) the ability to identify the angular direction of a gamma source from the instrument in conjunction with (B) a simultaneous high efficiency measurement of neutron radiation with essentially equal response from both thermal to fast (MeV) energies.

The ability to determine source direction is an aid to inspectors or first responders because it reduces the time required to locate, secure or remediate a potential radioactive threat. This reduces the exposure to first responders, subsequent somatic damage to others in the area as well as danger to those inspectors having to work in an unstable environment such as a boarded ship at sea.

Source direction is given as letters that correspond to the points on a compass (N, NE, E, etc with N being the front of the instrument. With appropriate graphics display hardware an instant and intuitive repesentation of the direction of maximum gamma intensity would be displayed. In a functional sense, this represents an image of the immediate radioactive environment surrounding the instrument.

MCNP simulations indicate an intrinsic angular resolution of about fifteen degrees. Both gamma and neutron counts as well as direction are displayed simultaneously in conjunction with audible alarms or tone proportional to radiation intensity.

The importance of a concurrent efficient neutron response capability eliminates an unnecessary intrinsic vulnerability of a gamma only system and is essential to having a comprehensive radiation monitoring capability. Actual nuclear weapons and fissile materials have relatively weak gamma signatures that may be easily disguised or shielded and subsequently not detected by a gamma only instrument. An adequate neutron response capability could be the difference between making or missing a critical detection and suffering a catastrophic result.

The identical patented concepts, principles and operational characteristics described for the portable instrument could be applied to a larger system that could be mounted on a small vehicle such as an ATV, utility truck, patrol boat or helicopter.

Delta Epsilon has conducted MCNP modeling on a gamma and neutron detector array that would include both high sensitivity neutron and gamma-ray directional measurements as well as radioelement identification by gamma ray spectral analysis. Neutron directional response will be in azimuth. The gamma direction will be determined in both azimuth and elevation giving a 3-D directional response.

SYNOPSIS OF PROPOSED INSTRUMENT FEATURES:

• Rapid survey of large areas from the sea, ground, or air. A seaborne instrument would have adequate sensitivity to preliminarily screen adjacent vessels without having to board them.

• Gamma sensitivity is 50 times greater than for hand held instruments meeting the ANSI N-42.33 sensitivity standard. For example, MCNP modeling indicates a response of 7,000 cps. for a 1mCi Cs-137 source at 5 meters.

• Gamma spectroscopy with readily available NaI is improved by potential for high precision spectra and large peak-to-Compton ratio.

• 3-D gamma directional array provides azimuthal and vertical source direction.

• Neutron sensitivity is about 14 times greater than the ANSI N42.34 and IAEA alarm standards for a hand held instrument. For example, response to fast neutrons is about 50 c/s for 1 ug Cf-252 at 5 meters. This sensitivity confers a significant neutron search capability.

• Both neutron and gamma source direction with angular resolution of better than 10 degrees.

Delta Epsilon is interested in a possible collaborative effort with an appropriate partner or entity to undertake further development and commercialization of these instruments and their unique capabilities. Interested and qualified parties should contact us for further details.

Read the rest of the details in our printable PDF RZ -133 Neutron/Gamma Ray Survey Instrument brochure or return to the Delta Epsilon Rediometric Instruments overview.

Please conact Delta Epsilon if you have questions or require additional information.