A procedure for benchmarking laboratory exposures with 1 A GeV iron ions.

A new version of the HZETRN code capable of simulating HZE ions with either laboratory or space boundary conditions is under development. The computational model consists of combinations of physical perturbation expansions based on the scales of atomic interaction, multiple scattering, and nuclear reactive processes with use of asymptotic/Neumann expansions with non-perturbative corrections. The code contains energy loss with straggling, nuclear attenuation, nuclear fragmentation with energy dispersion and downshifts, and off-axis dispersion with multiple scattering under preparation. The present benchmark is for a broad directed beam for 1 A GeV iron ion beams with 2 A MeV width and four targets of polyethylene, polymethyl metachrylate, aluminum, and lead of varying thickness from 5 to 30 g/cm2. The benchmark quantities will be dose, track averaged LET, dose averaged LET, fraction of iron ion remaining, and fragment energy spectra after 23 g/cm2 of polymethyl metachrylate.     

Introduction to space weather

The solar and interplanetary origin of space weather disturbances, as well as the related magnetospheric dynamics, will be presented. Besides the involved phenomenology in solar–terrestrial physics, some of the main effects of space weather variability concerning mankind in space and at the earth’s surface will also be discussed. The November 2003 event is shown as an example of the solar, interplanetary and magnetospheric aspects of a space weather storm.     

Statistical validation of HZETRN as a function of vertical cutoff rigidity using ISS measurements

Measurements taken in Low Earth Orbit (LEO) onboard the International Space Station (ISS) and transit vehicles have been extensively used to validate radiation transport models. Primarily, such comparisons were done by integrating measured data over mission or trajectory segments so that individual comparisons to model results could be made. This approach has yielded considerable information but is limited in its ability to rigorously quantify and differentiate specific model errors or uncertainties. Further, as exploration moves beyond LEO and measured data become sparse, the uncertainty estimates derived from these validation cases will no longer be applicable. Recent improvements in the underlying numerical methods used in HZETRN have resulted in significant decreases in code run time. Therefore, the large number of comparisons required to express error as a function of a physical quantity, like cutoff rigidity, are now possible. Validation can be looked at in detail over any portion of a flight trajectory (e.g. minute by minute) such that a statistically significant number of comparisons can be made. This more rigorous approach to code validation will allow the errors caused by uncertainties in the geometry models, environmental models, and nuclear physics models to be differentiated and quantified. It will also give much better guidance for future model development. More importantly, it will allow a quantitative means of extrapolating uncertainties in LEO to free space. In this work, measured data taken onboard the ISS during solar maximum are compared to results obtained with the particle transport code HZETRN. Comparisons are made at a large number (∼77,000) of discrete time intervals, allowing error estimates to be given as a function of cutoff rigidity. It is shown that HZETRN systematically underestimates exposure quantities at high cutoff rigidity. The errors are likely associated with increased angular variation in the geomagnetic field near the equator, the lack of pion production in HZETRN, and errors in high energy nuclear physics models, and will be the focus of future work.     

Proton lateral broadening distribution comparisons between GRNTRN,MCNPX, and laboratory beam measurements

Recent developments in NASA’s deterministic High charge (Z) and Energy TRaNsport (HZETRN) code have included lateral broadening of primary ion beams due to small-angle multiple Coulomb scattering, and coupling of the ion-nuclear scattering interactions with energy loss and straggling. This new version of HZETRN is based on Green function methods, called GRNTRN, and is suitable for modeling transport with both space environment and laboratory boundary conditions. Multiple scattering processes are a necessary extension to GRNTRN in order to accurately model ion beam experiments, to simulate the physical and biological-effective radiation dose, and to develop new methods and strategies for light-ion radiation therapy. In this paper we compare GRNTRN simulations of proton lateral broadening distributions with beam measurements taken at Loma Linda University Proton Therapy Facility. The simulated and measured lateral broadening distributions are compared for a 250 MeV proton beam on aluminum, polyethylene, polystyrene, bone substitute, iron, and lead target materials. The GRNTRN results are also compared to simulations from the Monte Carlo MCNPX code for the same projectile-target combinations described above.     

Plasma effects of active ion beam injections in the ionosphere at rocket altitudes

Data from ARCS rocket ion beam injection experiments will be primarily discussed in this paper. There are three results from this series of active experiments that are of particular interest in space plasma physics. These are the transverse acceleration of ambient ions in the large beam volume, the scattering of beam ions near the release payload, and the possible acceleration of electrons very close to the plasma generator which produce intense high frequency waves. The ability of 100 ma ion beam injections into the upper E and F regions of the ionosphere to produce these phenomena appear to be related solely to the process by which the plasma release payload and the ion beam are neutralized. Since the electrons in the plasma release do not convect with the plasma ions, the neutralization of both the payload and beam must be accomplished by large field-aligned currents (milliamperes/square meter) which are very unstable to wave growth of various modes. Future work will concentrate on the wave production and wave-particle interactions that produce the plasma/energetic particle effects discussed in this paper and which have direct application to natural phenomena in the upper ionosphere and magnetosphere.     

Space Research Plan of China's Space Stationormalsize

China's manned spaceflight missions have been introduced briefly, and the research planning of space sciences for China's Space Station (CSS) has been presented with the topics in the research areas, including:life science and biotechnology, microgravity fluid physics and combustion science, space material science, fundamental physics, space astronomy and astrophysics, earth sciences and application, space physics and space environment, experiments of new space technology. The research facilities, experiment racks, and supporting system planned in CSS have been described, including:multifunctional optical facility, research facility of quantum and optic transmission, and a dozen of research racks for space sciences in pressurized module, etc. In the next decade, significant breakthroughs in space science and utilization will hopefully be achieved, and great contributions will be made to satisfy the need of the social development and people's daily life.      

Space Research Plan of China's Space Station

China's manned spaceflight missions have been introduced briefly,and the research planning of space sciences for China's Space Station(CSS) has been presented with the topics in the research areas,including:life science and biotechnology,microgravity fluid physics and combustion science,space material science,fundamental physics,space astronomy and astrophysics,earth sciences and application,space physics and space environment,experiments of new space technology.The research facilities,experiment racks,and supporting system planned in CSS have been described,including:multifunctional optical facility,research facility of quantum and optic transmission,and a dozen of research racks for space sciences in pressurized module,etc.In the next decade,significant breakthroughs in space science and utilization will hopefully be achieved,and great contributions will be made to satisfy the need of the social development and people's daily life.     

Energetic ion emission for active spacecraft control

Future space missions aiming at the accurate measurement of cold plasmas and DC to very low frequency electric fields will require that the potential of their conductive surfaces be actively controlled to be near the ambient plasma potential. In the near-Earth space these spacecraft are usually solar-cell powered; consequently, parts of their surface are most of the time exposed to solar photons. Outside the plasmasphere, a positive surface potential due the dominance of surface-emitted photoelectrons over ambient plasma electrons is to be expected. Photo- and ambient electrons largely determine the potential and positive values between a few Volts up to 100 V have been observed. Active ion emission is the obvious solution of this problem. A liquid metal ion emitter and a saddle field ion emitter are nearing the stage of flight unit fabrication. We will attempt to clamp the spacecraft potential to values close to the plasma potential. We present first results from vacuum chamber tests and describe the emission behaviour and characteristics of emitters producing, respectively, In⁺ and N₂⁺ beams with an energy of ≥ 5 keV.     

Space physics and the teaching of undergraduate electromagnetism

Space physics is not a subject typically found in the undergraduate curriculum, and it is rare even at the graduate level. On the other hand, the basis of space physics is electromagnetism and the motion of charged particles, which are common topics in both the introductory and advanced undergraduate physics curriculum, and examples from space physics can be used to enliven instruction. In this paper, I will discuss various topics commonly found in both introductory and upper-division electricity and magnetism classes where examples from space physics may facilitate student understanding or provide interesting, real-life examples of electromagnetism in action.     

Science Researches of Chinese Manned Space Flight

With the complete success of the 2nd stage of Chinese Manned Space Program (CMSP), several science researches have been performed on Tiangong-1 experimental spacelab, which was docked with three Shenzhou spaceships one after another. The China's real spacelab, Tiangong-2 will be launched in 2015, docked with a Shenzhou spaceship soon. After six months, it will be docked with the first Chinese cargo ship (Tianzhou-1). More space science researches, involving with space biology, fluid physics, fundamental physics, materials science, Earth science, astronomy and space environmental science, will be operated on Tiangong-2 spacelab, and crewed and cargo spaceships. Furthermore, the considerable large-scale space utilization of Shina's Space Station is planned. The research fields include yet not limited to space medicine and physiology, space life science and biotechnology, fluid physics and combustion in microgravity, space material science, and fundamental physics in microgravity, space astronomy, Earth science, space physics and space environment utilization, technology demonstration.      

Science Research and Utilization Planning of China's Space Station in Operation Period 2022-2032

The core module of China's Space Station (CSS) is scheduled to be launched around the end of 2020, and the experimental module I and II will be launched in the next two years. After on-orbit constructions, CSS will be transferred into an operation period over 10 years (2022-2032 and beyond) to continuously implement space science missions. At present, based on the project selection and research work in the ground development period of CSS, China is systematically making a utilization mission planning for the operation period, which focuses on the fields of aerospace medicine and human research, space life science and biotechnology, microgravity fluid physics, combustion science, materials science, fundamental physics, space astronomy and astrophysics, Earth science, space physics and space environment, space application technology, etc. In combination with the latest development trend of space science and technology, China will continue to update planning for science research and technology development, carry out project cultivation, payload R&D, and upgrade onboard and ground experiment supporting systems to achieve greater comprehensive benefits in science, technology, economy, and society.      

Ground-based measurements of galactic cosmic ray fragmentation in shielding.

The mean free path for nuclear interactions of galactic cosmic-rays is comparable to shielding and tissue thicknesses present in human interplanetary exploration, resulting in a significant fraction of nuclear reaction products at depth. In order to characterize the radiation field, the energy spectrum, the angular distribution, and the multiplicity of each type of secondary particles must also be known as a function of depth. Reactions can take place anywhere in a thick absorber; therefore, it is necessary to know these quantities as a function of particle energy for all particles produced. HZE transport methods are used to predict the radiation field; they are dependent on models of the interaction of man-made systems with the space environment to an even greater extent than methods used for other types of radiation. Hence, there is a major need to validate these transport codes by comparison with experimental data. The most cost-effective method of validation is a comparison with ground-based experimental measurements. A research program to provide such validation measurements using neon, iron and other accelerated heavy ion beams will be discussed and illustrated using results from ongoing experiments and their comparison with current transport codes. The extent to which physical measurements yield radiobiological predictions will be discussed.     

天基X射线掠入射式成像望远镜发展现状

阐述了太阳X射线成像观测在空间天气预报中的地位和作用，叙述了掠入射式X射线聚焦成像的基本原理，简要介绍了在轨成功运行的天体X射线成像望远镜和太阳X射线成像望远镜的基本设计和技术指标，并介绍了国内正开发研制的专门服务于空间天气预报的太阳X射线成像望远镜基本设计和主要特点．     

High-LET radiation carcinogenesis.

Recent results for neutron radiation-induced tumors are presented to illustrate the complexities of the dose-response curves for high-LET radiation. It is suggested that in order to derive an appropriate model for dose-response curves for the induction of tumors by high-LET radiation it is necessary to take into account dose distribution, cell killing and the susceptibility of the tissue under study. Preliminary results for the induction of Harderian gland tumors in mice exposed to various heavy ion beams are presented. The results suggest that the effectiveness of the heavy ion beams increases with increasing LET. The slopes of the dose-response curves for the different high-LET radiations decrease between 20 and 40 rads and therefore comparisons of the relative effectiveness should be made from data obtained at doses below about 20-30 rads.     

Bodies in flowing plasmas: Laboratory studies

A brief review of early laboratory investigations of bodies in flowing, rarefied plasmas is given together with a discussion of more recent parametric studies carried out at NASA/Marshall Space Flight Center (MSFC), which include the effects of the ion acoustic Mach number and the normalized test body potential. Good agreement is found between the experimental results and theoretical calculations which omit ion thermal motion. The relation between laboratory investigations and the results of satellite-borne measurements is addressed. This relationship has led to an appreciation for the benefits of applying the methods and techniques of laboratory plasma physics to investigations in space, where several limitations inherent to the laboratory can be circumvented. These types of investigations, conducted in Earth orbit, can enhance our understanding of space plasma physics and have direct application to certain types of solar system phenomena.     

Simulation of X-ray and gamma ray detector response and spectral deconvolution

A detailed Monte-Carlo code has been developed from basic principles that simulates the responses of high energy photon detectors to incident beams of photons. The detector response matrice (DRM)s are calculated using this code. Deconvolution of an artificially generated spectrum is presented.     

The FLUKA code for space applications: recent developments.

The FLUKA Monte Carlo transport code is widely used for fundamental research, radioprotection and dosimetry, hybrid nuclear energy system and cosmic ray calculations. The validity of its physical models has been benchmarked against a variety of experimental data over a wide range of energies, ranging from accelerator data to cosmic ray showers in the earth atmosphere. The code is presently undergoing several developments in order to better fit the needs of space applications. The generation of particle spectra according to up-to-date cosmic ray data as well as the effect of the solar and geomagnetic modulation have been implemented and already successfully applied to a variety of problems. The implementation of suitable models for heavy ion nuclear interactions has reached an operational stage. At medium/high energy FLUKA is using the DPMJET model. The major task of incorporating heavy ion interactions from a few GeV/n down to the threshold for inelastic collisions is also progressing and promising results have been obtained using a modified version of the RQMD-2.4 code. This interim solution is now fully operational, while waiting for the development of new models based on the FLUKA hadron-nucleus interaction code, a newly developed QMD code, and the implementation of the Boltzmann master equation theory for low energy ion interactions.     

Results of measurements of the response of a delta-doped CCD to neutral and charged particle beams

We report the measurements of the response of a delta-doped Charge Coupled Device (CCD) in imaging mode to beams of charged and neutral particles. That is, the detector imaged the incident beam over its 1024 × 1024 pixels, integrating the number of particles counted in each pixel during the exposure period. In order to count individual particles the exposure time would have had to be reduced considerably compared to the typical ?5 s used in these studies. Our CCD thus operated in a different manner than do conventional particle detectors such as the CEM and MCP that normally are used in a particle counting mode. The measurements were carried out over an energy range from 0.8 to 30 keV. The species investigated include H, H⁺, He⁺, N⁺, N₂⁺, and Ar⁺. The energy and ion mass covered wider ranges than previous measurements for the CCD. The results of these measurements show, as in the case of the previous measurement, for a given ion the CCD response increases with energy and for a given particle energy the response decreases with increasing mass of the particle. These results are in agreement with predictions of the theory of the range of ions in solids. The results also show the possibility for the application of the delta doped CCD as a detector for low energy particle measurements for space plasma physics applications.