Bremsstrahlung effects in energetic particle detectors (original) (raw)
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Journal of Geophysical Research, 1965
A set of scintillation counters was carried on polar-orbiting Air Force satellites in the last half of 1961. Cosmic-ray effects were observed at high latitudes with good statistics. The L value of the 'edge' of the cosmic-ray plateau was found to vary with longitude and to vary between L-2.7 and L-3.3. This corresponds to a 'knee' at from L-3.1 to L-3.7. A 'kneecap,' consistently observed at the plateau edge, is interpreted as the appearance of reentrant albedo as the satellite moves to lower latitudes. The relative amount of this albedo was 8 ñ 2% at an altitude of 300 km. A day-night effect in the observed high-latitude reentrant albedo cutoff is consistent with known day-night changes in the magnetosphere. The observed altitude dependence of flux at very high latitudes is used to derive an omnidirectional interplanetary flux of 2.6 __+ 0.3 particles/cm • sec at this time. Perigee 150 km Period 91.5 min Tumble None Detectors carried CsI Small fluor 9/17-9/23 11/5-11/11 12/13 only 83ø 83 ø 81 ø 410 km (32 øS) 1000 km (32 øS) 500 km (38 øS) 240 km 245 km 240 km 90.9 min 97.1 min 91.8 min Starting between Starting approxi-None orbit 30 and 41 mately orbit 9 with period of a with period of a few tens of seconds few minutes CsI CsI CsI Small fluor Small fluor Small fiuo• Large fluor Large fluor Electron spectrom-Electron spectrometer eter Univ. Chicago Univ. Chicago lowcounter tele-energy proton scope detector Neutron Neutron Univ. Chicago high-energy proton telesc6'pe energy; it rose to a maximum of 50% at 150 key, fell to 25% at 300 key, and to 10% at 1 Mev, which was the highest energy used in the calibration. The proton threshold was calculated to be at E• • 2.5 Mev for protons incident normal to the Be window. This detector was directional, was mounted on the vehicle to look at the local zenith, and was collimated to be sensitive to particles incident in a cone of halfangle approximately 70 ø. The 'small' fluor detector consisted of a 6-inchlong, 2.5-inch-diameter plastic scintillator bonded to an Ascop 541A photomultiplier. This small fluor was completely surrounded by a 0.050-inch A1 case. Discriminators were set so the threshold was 0.5 Mev energy deposited in the scintillator. This detector was omnidirectional except where shielded by the vehicle. The vehicle shielding varied from ~25% for lowenergy (<100 Mev) protons to <•5% at very high energies (>1 bey). This detector was capable of detecting minimum ionizing particles. Thresholds calculated using range-energy tables are listed in Table 2. The 'large' fluor detector consisted of a larger cylindrical plastic scintillator viewed by a CBS CL 1106 photomultiplier. It was surrounded by 1.5 g/cm • of Pb and A1. Discriminators were set TABLE 2. Detector Characteristics Detector Proton Minimum Detection Shielding Geometry and Area Threshold Direct Electron Electron Bremsstrahlung Detection Detection Threshold Threshold CsI Small fluor Large fluor 0.01 g/cm • Be Directional, cone of half-angle •70 ø, area-5 cm • 0.5 g/cm' A1 Omnidirectional, omnidirectional cross section-158 cm •.
Electron calibration of a high-energy cosmic ray detector
Nuclear Instruments and Methods, 1973
The response of the GSFC High Energy Cosmic Ray Detector has been studled usmg electrons m the energy range 5 4 to 18 GeV. A serm-emplrlcal analytic form has been developed to determme the startmg pomts and the energies of electron-Induced cascade showers
Scientific Goals and In-orbit Performance of the High-energy Particle Detector on Board the CSES
The Astrophysical Journal Supplement Series, 2019
The CSES satellite aims to monitor electromagnetic-, particle-and plasma perturbations in the ionomagnetosphere and inner Van Allen radiation belts, originated by electromagnetic sources external and internal to the geomagnetic cavity, cosmic rays and solar events. In particular, the objective of the space mission is to investigate lithosphere-atmosphere-ionosphere coupling mechanisms (including effects of lightning, earthquakes, volcanoes and artificial electromagnetic emissions) that induce perturbations of the top side of the ionosphere and lower boundary of the radiation belts. To this purpose, the mission has been conceived to take advantage of a multi-instrument payload comprising nine detectors for the measurement of electromagnetic field components, plasma parameters and energetic particles, as well as X-ray flux. The Italian team participating in the CSES mission has built one of these devices, the High-Energy Particle Detector (HEPD), for high-precision observations of electrons, protons and light nuclei. During its trip along the orbit, and thanks to the large set of detectors operated on board, CSES completely monitors the Earth, acting as an excellent instrument for Space Weather.
Scientific Goals and In-orbit Performance of the High-energy Particle Detector on Board the CSES
Astrophysical Journal Supplement Series, 2019
The CSES satellite aims to monitor electromagnetic-, particle-and plasma perturbations in the ionomagnetosphere and inner Van Allen radiation belts, originated by electromagnetic sources external and internal to the geomagnetic cavity, cosmic rays and solar events. In particular, the objective of the space mission is to investigate lithosphere-atmosphere-ionosphere coupling mechanisms (including effects of lightning, earthquakes, volcanoes and artificial electromagnetic emissions) that induce perturbations of the top side of the ionosphere and lower boundary of the radiation belts. To this purpose, the mission has been conceived to take advantage of a multi-instrument payload comprising nine detectors for the measurement of electromagnetic field components, plasma parameters and energetic particles, as well as X-ray flux. The Italian team participating in the CSES mission has built one of these devices, the High-Energy Particle Detector (HEPD), for high-precision observations of electrons, protons and light nuclei. During its trip along the orbit, and thanks to the large set of detectors operated on board, CSES completely monitors the Earth, acting as an excellent instrument for Space Weather.
Radiation Measurements
One of the many risks of long-duration space flights is the excessive exposure to cosmic radiation, which may have serious consequences particularly during solar flares and higher solar activity. Since space radiation mainly consists of charged heavy particles, the equivalent dose differs significantly from the absorbed dose. The objectives of this project, which began in the KFKI Atomic Energy Research Institute of the Hungarian Academy of Sciences several years ago, are to develop a three-dimensional silicon detector telescope (TriTel) and to develop software for data evaluation of the measured energy deposition spectra. A version of TriTel will be installed onboard a European satellite (ESEO) in a highly eccentric orbit crossing, the Van Allen belts. The instrument will encounter high fluxes of trapped electron radiation in a considerable part of the orbit. In order to give a rough estimate of the expected fluxes and spectra of protons and electrons in orbit, calculations were ma...
A software toolkit to simulate activation background for high energy detectors onboard satellites
Space Telescopes and Instrumentation 2020: Ultraviolet to Gamma Ray, 2020
A software toolkit for the simulation of activation background for high energy detectors onboard satellites is presented on behalf of the HERMES-SP 1 collaboration. The framework employs direct Monte Carlo and analytical calculations allowing computations two orders of magnitude faster and more precise than a direct Monte Carlo simulation. The framework was developed in a way that the model of the satellite can be replaced easily. Therefore the framework can be used for different satellite missions. As an example, the proton induced activation background of the HERMES CubeSat is quantified.
Energetic particle monitoring in space: three-decades of experience at IEPSAS
IEPSAS in Košice, Slovakia has a long track of experience with the design, construction, testing and operating of energetic particle detectors at low-altitude and high-apogee satellites as well as interplanetary probes during past 30 years. A review of experiments in space and a brief survey of selected results with references is presented. A simple programmable energetic particle detector MEP-1 developed for COMPASS microsatellite is described with more details. The device can be used for both scientific and application tasks at LEO. In addition to the scientific studies of near Earth environment, the experience obtained can be used in the future also for commercial satellites, where relatively simple, monitoring type of devices for measurement of radiation, especially due to the effects of space weather, are of relevance.
Experimental Check of Bremsstrahlung Dosimetry Predictions for 0.75 MeV Electrons
IEEE Transactions on Nuclear Science, 2000
Bremsstrahlung dose in CaF2 TLDs from the radiation produced by 0.75 MeV electrons incident on Ta/C targets is measured and compared with that calculated via the CYLTRAN Monte Carlo code. The comparison was made to validate the code, which is used to predict and analyze radiation environments of flash x-ray simulators measured by TLDs. Over a wide range of Ta target thicknesses and radiation angles the code is found to agree with the 5% measurements.
The evaluation of the radiation hazards on components used in space environment is based on the knowledge of the radiation level encountered on orbit. The models that are widely used to assess the near-Earth environment for a given mission are empirical trapped radiation models derived from a compilation of spacecraft measurements. However, these models are static and hence are not suited for describing the short timescale variations of geomagnetic conditions. The transient observation-based particle (TOP)-model tends to break with this classical approach by introducing dynamic features based on the observation and characterization of transient particle flux events in addition to classical mapping of steady-state flux levels. In order to get a preliminary version of an operational model (actually only available for electrons at low Earth orbit, LEO), (i) the steady-state flux level, (ii) the flux enhancements probability distribution functions, and (iii) the flux decay-time constants (at given energy and positions in space) were determined, and an original dynamic model skeleton with these input parameters has been developed. The methodology is fully described and first flux predictions from the model are presented. In order to evaluate the net effects of radiation on a component, it is important to have an efficient tool that calculates the transfer of the outer radiation environment through the spacecraft material, toward the location of the component under investigation. Using the TOP-model space radiation fluxes and the transmitted radiation environment characteristics derived through GEANT4 calculations, a case study for electron flux/dose variations in a small silicon volume is performed. Potential cases are assessed where the dynamic of the spacecraft radiation environment may have an impact on the observed radiation effects.
The Energetic Particle Detector
Astronomy & Astrophysics, 2020
After decades of observations of solar energetic particles from space-based observatories, relevant questions on particle injection, transport, and acceleration remain open. To address these scientific topics, accurate measurements of the particle properties in the inner heliosphere are needed. In this paper we describe the Energetic Particle Detector (EPD), an instrument suite that is part of the scientific payload aboard the Solar Orbiter mission. Solar Orbiter will approach the Sun as close as 0.28 au and will provide extra-ecliptic measurements beyond ∼30° heliographic latitude during the later stages of the mission. The EPD will measure electrons, protons, and heavy ions with high temporal resolution over a wide energy range, from suprathermal energies up to several hundreds of megaelectronvolts/nucleons. For this purpose, EPD is composed of four units: the SupraThermal Electrons and Protons (STEP), the Electron Proton Telescope (EPT), the Suprathermal Ion Spectrograph (SIS), a...