As Flown on Cosmos 1129
The detector packets include stacks of plastic nuclear track detectors (PNTDs) for measurements of high-LET (linear energy transfer) particles (Z >= 6), and thermoluminescent detectors (TLDs) and radiator foil detectors for measurement of total doses due to charged particles and gamma rays.
Cosmos 1129 Corner Stacks*: The corner stacks are designed to contain both TLDs, for measuring the total absorbed dose, and particle radiator detectors, for measuring the neutron fluences.
Interior Plastic Stacks: The PNTD stacks in the interior module consist of alternating layers of three different detector types. A single repeat contains four ordered layers of the plastic types: GE Lexan polycarbonate, American Acrylics CR-39, Lexan, and Kodak Pathe cellulose nitrate (CN); with respective nominal layer thicknesses of 190 °m, 1,000 °m, 190 °m, and 100 °m. This sequence is repeated a sufficient number of times to comprise the entire thickness of each of the stacks. The arrangement of the plastic stacks along the three orthogonal directions is the preferred configuration because of the somewhat anisotropic response of the detectors (they responded to lower LET particles at normal incidence than at grazing incidence).
Exterior Plastic Stacks: The exterior PNTD stacks consist of alternating layers of Lexan and CN sandwiched between the two layers of CR-39. One surface of each stack is exposed directly to the space environment except for a very thin evaporated layer of aluminum to reduce the UV exposure and temperature during the mission.
Exterior TLD Packets: The external TLD packets contain six TLD chips each of 7LiF and CaF2 for total absorbed dose measurements outside the hull of the spacecraft. The TLD chips are held in twelve square milled holes, 0.635 cm in dimensions, in an aluminum plate. The two TLD types are placed in alternate spaces and are spread, approximately equally, across the external packet dimension. An aluminum top plate, 0.318 cm thick, protects the TLDs from the external environment.
A set of radiation dosimetry and spectrometry measurements were conducted using passive detector systems located inside and outside the Cosmos 1887 spacecraft. Various versions of the different components of these systems are flown in different arrangements on other Cosmos missions, such as Cosmos 936 and 1129 Radiation Detector Packets and Cosmos 2044 Radiation Dosimeters. All detectors for outside the spacecraft were held in a "clamshell" style container which was closed before re-entry to prevent heating of detectors in the atmosphere.
Lexan Box Detector Assembly (LBDA): The assembly contains Plastic Nuclear Track Detector (PNTD) stacks, a set of thermoluminescent detectors (TLDs) and a nuclear emulsion stack. The components are placed in a Lexan polycarbonate plastic box, with the five PTNDs (one thick center stack, 2.255 in2, plus four thin side stacks, 1.320 x 2.255 in) arranged in an orthogonal array to compensate for the angular response of PTNDs. The PTNDs used were special, high-sensitivity CR-39, plus several sheets of Tuffak polycarbonate detector. Heavy particle LET (linear energy transfer) spectrum is measured with the PNTD stacks. Emulsions are included for high-energy proton flux measurements.
Thermoluminescent Detector Assembly (TDA): Two identical flight units each containing two thin stacks and one thick stack of TLDs are used to measure depth doses (total absorbed dose) outside the spacecraft. The flight unit consisted of an aluminum cylinder of 5 cm diameter and 1.99 cm thickness with cylindrical holes to accommodate TLD stacks. An aluminized double-window of Kapton plastic totaling 15 °m serves to hold in the stacks and protects them from direct sunlight, heat, and vibration. In thin stacks, thirty thin TLD chips (9.14 x10-3 cm) are placed at the tops, and twelve thicker (0.889 cm) TLD chips at the bottoms. For the thick stacks, sixteen of the thicker TLD chips are stacked. All TLDs are 7Lif and separated by 15-°m-thick polycarbonate film. Strips of stiff, 0.015-cm-thick paper is placed beneath all stacks and on the sides (4) of the thick stacks for protection against vibration and movement.
Sealed Plastic Stacks (SPS): The stacks measure heavy particle LET spectra as a function of shielding depth in plastic outside the spacecraft. Doses and dose equivalents are also generated for the heavy particles. Hardware consists of two hermetically sealed flight units containing PTND stacks with aluminized Kapton double-windows, as above. PTND stacks are 3 cm in diameter and 1.4 cm thick and include sets of CR-39, Tuffak polycarbonate, and Cronar polyester detectors.
Outside Activation Foil Assembly (OAFA): The outside foil assembly measures neutron fluences outside the spacecraft. The two flight units contain 59Co activation foils and PNTD films. An aluminum frame with aluminized Kapton double-windows is placed above the detectors, while the sides of the units were left open to vacuum. PNTDs of Tuffak polycarbonate and Cronar polyester are used for an intercomparison between those open to vacuum and those hermetically sealed (SPS, above). Due to space limitations, CR-39 is not included.
Inside Activation Foil Assembly (IAFA): The inside foil assembly uses a single 59Co activation foil to measure neutron fluences inside the spacecraft. The assembly is placed near the LBDA.