High LET particle radiation inside skylab (SL2) command module.

The design of a portable three-band cosmic-ray neutron detector is reported in this article. This instrument has been designed to characterise cosmic ray neutron fields in the upper atmosphere and in cosmic reference field facilities. The design utilises a spherical moderator with a layer of spallation material covering a central (3)He proportional counter. The instrument incorporates twelve lithium-coated diodes, six on the outside of the polyethylene layer and six placed within the structure. The dimensions, materials and arrangement of these in the instrument have been optimised with MCNPX to provide a compromise between the requirements of portability and spectral response.

Cosmic Radiation↗

PubMed2006

MIDN: a spacecraft microdosimeter mission.

MIDN (MIcroDosimetry iNstrument) is a payload on the MidSTAR-I spacecraft (Midshipman Space Technology Applications Research) under development at the United States Naval Academy. MIDN is a solid-state system being designed and constructed to measure microdosimetric spectra to determine radiation quality factors for space environments. Radiation is a critical threat to the health of astronauts and to the success of missions in low-Earth orbit and space exploration. The system will consist of three separate sensors, one external to the spacecraft, one internal and one embedded in polyethylene. Design goals are mass <3 kg and power <2 W. The MidSTAR-I mission in 2006 will provide an opportunity to evaluate a preliminary version of this system. Its low power and mass makes it useful for the International Space Station and manned and unmanned interplanetary missions as a real-time system to assess and alert astronauts to enhanced radiation environments.

Cosmic Radiation↗

PubMed2006

Past and future application of solid-state detectors in manned spaceflight.

The radiation exposure in space missions can be reduced by careful mission planning and appropriate measures, such as provision of a radiation shelter, but it cannot be eliminated. The reason for that is the high penetration capability of the radiation components owing to their high energies. Radiation is therefore an acknowledged primary concern for manned spaceflight and is a potentially limiting factor for long-term orbital and interplanetary missions. The radiation environment is a complex mixture of charged particles of solar and galactic origin and of the radiation belts, as well as of secondary particles produced in interactions of the galactic cosmic particles with the nuclei of atmosphere of the earth. The complexity even increases by placing a spacecraft into this environment owing to the interaction of the radiation components with the shielding material. Therefore it is a challenge to provide for appropriate measurements in this radiation field, coping with the limited resources on experiment power and mass. Solid-state dosemeters were already chosen for measurements in the first manned flights. Thermoluminescence dosemeters (TLDs) and plastic nuclear track detectors (PNTD) especially found a preferred application because they are light-weighted, need no power supply and they are tissue-equivalent. Most of the data available until 1996 were gathered by using these passive detectors; this especially holds for heavy ion particle spectra. The systems, supplemented by converter foils or fission detectors and bubble detectors, provide information on dose, particle flux-, energy- and linear energy transfer spectra of the ionising radiation and neutron fluxes and doses. From 1989, silicon detectors were used for dose and flux measurements and later on for particle spectrometry. Silicon detectors were demonstrated as a powerful tool for the description of space radiation environment. Optical simulated luminescence (OSL) detectors have now been introduced as a new system in space research. Both, OSL and superheated drop detectors are candidates for personal dosimetry systems. The article will summarise past results, and results of measurements performed recently on the ISS, and conclude with future aspects.

Cosmic Radiation↗