Exposure to space radiation will be a limiting factor in future missions beyond low Earth orbit, such as to Mars. Mission durations will range from many days to weeks and many months, all spent outside the geomagnetic field, exposed to chronic galactic cosmic rays (GCR) as well as periodic solar particle events (SPE). Experiments in space are difficult and expensive. While it is not feasible to replicate the full space radiation environment on the ground, some particle accelerators are capable of producing significant components of the GCR. From the late 1990s through the present day HIMAC has been one of the most important such facilities. In this section we review a number of experiments in which HIMAC has been used to further international research in space radiation physics and biology, including radiation shielding, detector development for crewed and robotic spacecraft, radiation effects on biological organisms and electronics.
Measurements of nuclear fragmentation cross sections and of particle production in thick targets are needed for the development of space radiation shielding. Cross sections are used as source terms for models of fragmentation and transport, and thick target measurements for model validation and to evaluate candidate shielding materials and concepts. Here we briefly review how HIMAC ion beams have been used to simulate elements of the space radiation field for cross section and thick target measurements.
The ICCHIBAN project was an international collaboration to intercalibrate and intercompare the response of the different detectors and instruments used for radiation dosimetry aboard manned spacecraft. The objectives of the ICCHIBAN project were: 1) to determine the response of space radiation instruments and dosimeters to heavy ions of charge and energy similar to that found in the galactic cosmic radiation (GCR) spectrum; 2) to compare the response and sensitivity of various space radiation monitoring instruments and aid in reconciling differences in measurements made by various radiation instruments during space flight; and 3) to establish and characterize a heavy ion “reference standard” against which space radiation instruments can be calibrated. ICCHIBAN experiments were carried out at a number of particle accelerator facilities, the vast majority, eight, using the HIMAC heavy ion accelerator at the National Institute for Radiological Sciences, Chiba, Japan. Benefits of the ICCHIBAN project included the identification and correction of problems in calibration and data interpretation of a number of active space radiation instruments, and the demonstration of the overall efficacy and reproducibility of passive radiation dosimeters, especially luminescence-based detectors such as TLD and OSLD used in conjunction with CR-39 PNTD.
Space radiation exposures are distinct from those in charged particle radiotherapy in that they are typically low dose, low dose rate and mixed field. It is not feasible to exactly replicate these conditions in ground-based facilities, but carefully designed experiments at HIMAC have provided insight into the biological effects of space radiation.
The mechanisms of Single Event Effects (SEEs) on Silicon Carbide (SiC) power devices are becoming clearer. However, to completely understand the mechanisms of SEEs on SiC power devices and to explore radiation hardened technologies for SiC power devices, it is necessary to study the radiation response of SiC power devices using high-energy heavy ions at accelerator facilities such as the Heavy Ion Medical Accelerator in Chiba (HIMAC). The radiation hardening test methodology using high energy heavy ions is reviewed and the application of HIMAC for SEE testing is introduced with recent results from tests of SiC power devices.
A variety of radiation detectors and instruments have been deployed to characterize the radiation environment in low and high Earth orbit, lunar orbit, Mars orbit and on the surface of Mars. Here we discuss the testing and calibration of these detectors using HIMAC ion beams.