As Flown on Cosmos 936
A joint US - USSR flight experiment package contains a number of US radiation detectors designed mainly to determine physical parameters of different components of radiation in space. The joint flight experiment included the objective of elucidating results from Cosmos 782 which contained an unexplained difference in HZE flux values measured by American and Soviet investigators. The flight package consists of three separate parts: a US, 25% part which was located at one end of the experiment container; a USSR, 25% part located at the opposite end of the container; and a joint 50% part in the central region of the container. Detector materials from the 50%, joint portion are shared equally by US and USSR investigators.
Plastic Nuclear Track Detector (PNTD): Measurement of HZE (high-energy ionized) particle radiation is passively accomplished with plastic radiation detectors. PNTDs are located in the joint portion of the flight container and on the face of the US detector package.
US Detector Package: Several types of detectors are flown in the US detector package in order to measure neutron fluxes present in the spacecraft. These are all passive integrating devices, employgin either thermoluminescent detectors (TLDs) or track etch as the sensitive recording medium. In the first case, the high cross section of the 6LI(n,T)4He reaction in LiF TLDs is used. In the second, various radiator foils are sandwiched against cellulose nitrate plastic or moscovite mica which record the tracks of either 4He particles or fission fragments, respectively.
Lithium Fluoride (LiF) Thermoluminescent Detector (TLD): The TLDs are of both 6LiF and 7LiF types. The chips are 0.635 cm square and 0.089 cm thick. The chips are composed of pure extruded LiF. Discrimination on the basis of the high neutron cross section of 6Li can be made from the measurement differences between the two materials. Neutron measurements can be made in the presence of relatively large absorbed doses from other particles by this method.
Radiation Foil Detector Packet: Detectors having particle radiators composed of 6LiF, 181Ta, 209Be, 232Th, and 238U are included in the packet. The first of these employs cellulose nitrate plastic to register the 4He particles from the 6Li(n,T)4He reaction. The remainder contain mica to register fission fragments from the (n,f) reactions. The thickness of the 6LiF radiator foils are 4.5 mg/cm2. The thicknesses of the fission foils vary, but all are thicker than the ranges of the fission fragment produced. This gives the fission foil detectors maximum efficiency, since there is little attenuation of the detached neutrons through the foils. 6Li detectors require a self-shielding correction.
Nuclear Emulsions: Measurement of the proton exposure component is accomplished by Ilford nuclear emulsions of the G.5 (25 micrometers and 50 micrometers) K.2 (100 micrometers) type. Each emulsion is mounted on a 178 micrometer Melinex substrate, and one of each type inserted into a 0.006 inch thick black polyethylene bag, heat-sealed to ensure a light-tight container. Each such emulsion packet (3.8 x 5.1 cm) is then inserted, along with several plastic layers, into another black bag, forming a single "orthoganol" detector. Twelve US packets were attached to the joint US - USSR foam cube and to the US detector package.