Jack Miller

Lawrence Berkeley National Laboratory | LBL

Space biology research aims to understand fundamental spaceflight effects on organisms, develop foundational knowledge to support deep space exploration and, ultimately, bioengineer spacecraft and habitats to stabilize the ecosystem of plants, crops, microbes, animals and humans for sustained multi-planetary life. To advance these aims, the field l...

Human exploration of deep space will involve missions of substantial distance and duration. To effectively mitigate health hazards, paradigm shifts in astronaut health systems are necessary to enable Earth-independent healthcare, rather than Earth-reliant. Here we present a summary of decadal recommendations from a workshop organized by NASA on art...

The era of high-throughput techniques created big data in the medical field and research disciplines. Machine intelligence (MI) approaches can overcome critical limitations on how those large-scale data sets are processed, analyzed, and interpreted. The 67th Annual Meeting of the Radiation Research Society featured a symposium on MI approaches to h...

Human space exploration beyond low Earth orbit will involve missions of significant distance and duration. To effectively mitigate myriad space health hazards, paradigm shifts in data and space health systems are necessary to enable Earth-independence, rather than Earth-reliance. Promising developments in the fields of artificial intelligence and m...

Space biology research aims to understand fundamental effects of spaceflight on organisms, develop foundational knowledge to support deep space exploration, and ultimately bioengineer spacecraft and habitats to stabilize the ecosystem of plants, crops, microbes, animals, and humans for sustained multi-planetary life. To advance these aims, the fiel...

In addition to microgravity, spaceflight simultaneously exposes biology to a suite of other stimuli. For example, in space, organisms experience ionizing radiation environments that significantly differ in both quality and quantity from those normally experienced on Earth. However, data on radiation exposure during space missions is often complex t...

We developed a highly-selective technique to measure the energy loss and linear-energy-transfer (LET) spectra of energetic charged particles in high-resolution and over a large collection of particle-event types. Precise and wide-range spectral and tracking measurements were performed with a single semiconductor pixel detector. The quantum-counting...

Research on astronaut health and model organisms have revealed six features of spaceflight biology that guide our current understanding of fundamental molecular changes that occur during space travel. The features include oxidative stress, DNA damage, mitochondrial dysregulation, epigenetic changes (including gene regulation), telomere length alter...

Background: Ionizing radiation from galactic cosmic rays (GCR) is one of the major risk factors that will impact the health of astronauts on extended missions outside the protective effects of the Earth’s magnetic field. The NASA GeneLab project has detailed information on radiation exposure using animal models with curated dosimetry information fo...

The space radiation environment is a complex mixture of particle types and energies originating from sources inside and outside of the galaxy. These environments may be modified by the heliospheric and geomagnetic conditions as well as planetary bodies and vehicle or habitat mass shielding. In low Earth orbit (LEO), the geomagnetic field deflects a...

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.

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...

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 diffi...

Space radiation has recently been considered a risk factor for astronauts’ cardiac health. As an example, for the case of how to query and identify datasets within NASA’s GeneLab database and demonstrate the database utility, we used an unbiased systems biology method for identifying key genes/drivers for the contribution of space radiation on the...

Accurate assessment of risks of long-term space missions is critical for human space exploration. It is essential to have a detailed understanding of the biological effects on humans living and working in deep space. Ionizing radiation from galactic cosmic rays (GCR) is a major health risk factor for astronauts on extended missions outside the prot...

Radiation on the Martian Surface: Model Comparisons with Data from the Radiation Assessment Detector on the Mars Science Laboratory (MSL/RAD): Results from the 1st Mars Space Radiation Modeling Workshop - Special Issue

Highly ionizing atomic nuclei HZE in the GCR will be a significant source of radiation exposure for humans on extended missions outside low Earth orbit. Accelerators such as the LBNL Bevalac and the BNL AGS, designed decades ago for fundamental nuclear and particle physics research, subsequently found use as sources of GCR-like particles for ground...

Abstract Most accelerator-based space radiation experiments have been performed with single ion beams at fixed energies. However, the space radiation environment consists of a wide variety of ion species with a continuous range of energies. Due to recent developments in beam switching technology implemented at the NASA Space Radiation Laboratory (N...

A major attribute of the Water Walls Life Support Architecture is its potential to provide radiation shielding in addition to its air revitalization, climate control, contaminant control, and waste processing functions. This section describes the method and results of a series of preliminary particle beam tests conducted in the HIMAC Accelerator in...

The available nuclear fragmentation data relevant to space radiation studies are reviewed. It is found that there are serious gaps in the data. Helium data are missing in the intervals 280 MeV n-3 GeV n and >15 GeV n. Carbon data are missing >15 GeV n. Iron projectile data are missing at all energies except in the interval 280 MeV n-3 GeV n.

Human space flight requires protecting astronauts from the harmful effects of space radiation. The availability of measured nuclear cross-section data needed for these studies is reviewed in the present paper. The energy range of interest for radiation protection is approximately 100 MeV/n–10 GeV/n. The majority of data are for projectile fragmenta...

In this letter we focus on the new SI definition of the kilogram, and specifically that it fails to meet three of the generally accepted criteria for a good reference quantity: comprehensibility and realizability, general availability and invariance.

This paper describes a new mathematical method called conflation for consolidating data from independent experiments that measure the same physical quantity. Conflation is easy to calculate and visualize and minimizes the maximum loss in Shannon information in consolidating several independent distributions into a single distribution. A formal math...

It is widely accepted that improvement of the current International System of Units (SI) is necessary, and that central to this problem is redefinition of the kilogram. This paper compares the relative advantages of two main proposals for a modern scientific definition of the kilogram: an 'electronic kilogram' based on a fixed value of Planck's con...

Exposures were made with Medipix2 TimePix-based Si detectors at the HIMAC facility in Japan to explore the potential for discrimination between tracks with differing charges and energies, but with very similar dE/dx values. Data were taken at 15° increments for a number of different beams including 600 and 800MeV/A Si, 180MeV/A Ne and 100MeV/A O. D...

We report fragmentation cross sections measured at 0 deg for beams of 14-N, 16-O, 20-Ne, and 24-Mg ions, at energies ranging from 290 MeV/nucleon to 1000 MeV/nucleon. Beams were incident on targets of C, CH2, Al, Cu, Sn, and Pb, with the C and CH2 target data used to obtain hydrogen-target cross sections. Using methods established in earlier work,...

To meet the challenge of future deep space programs, an accurate and efficient engineering code for analyzing the shielding requirements against high-energy galactic heavy ion radiation is needed. In consequence, a new version of the HZETRN code capable of simulating high charge and energy (HZE) ions with either laboratory or space boundary conditi...

We report fragmentation cross sections measured at 0ˆ for beams of 14N, 16O, 20Ne, and 24Mg ions, at energies ranging from 290 MeV/nucleon to 1000 MeV/nucleon. Beams were incident on targets of C, CH2, Al, Cu, Sn, and Pb, with the C and CH2 target data used to obtain hydrogen-target cross sections. Using methods established in earlier work, cross s...

A critical need for NASA is the ability to accurately model the transport of heavy ions in the Galactic Cosmic Rays (GCR) through matter, including spacecraft walls, equipment racks, etc. Nuclear interactions are of great importance in the GCR transport problem, as they can cause fragmentation of the incoming ion into lighter ions. Since the radiat...

This article reviews several recent proposed redefinitions of the kilogram, and compares them with respect to practical realizations, uncertainties (estimated standard deviations), and educational aspects.

In preparation for the development of an active Space Radiation Dosimeter based on the Medipix2 pixel ASIC technology developed at CERN in Geneva, Switzerland, exposures were made at the HIMAC facility in Japan with a TimePix-based version with a Si detector layer to explore the potential for discrimination between tracks with differing charges and...

Pion production by collisions of relativistic heavy ions has been studied recently. For the reaction 1.05 GeV/A Ar + Ca pion (+), they discovered a peak in the invariant cross section at mid-rapidity at P/sub perpendicular/approximately 0.5 m/sub pion/c. This peak is not apparent in the 730 MeV p(+)p and was attributed to possible hydrodynamic flow...

Motivated by differences in the predicted fragmentation of heavy ions at energies around 5 GeV/A as employed in the event generators used by the FLUKA Monte Carlo Code [1], a set of measurements were carried out at the AGS facility at the Brookhaven National Laboratory to determine as much information as possible about the cross sections to allow h...

Cosmic radiation shielding properties are important for spacecraft, and hydrogenous materials such as polyethylene have been shown to be effective in shielding against galactic cosmic rays and solar energetic particles. Ultrahigh molecular weight polyethylene (UHMWPE) fibers, which are effective in such shielding, also have advanced mechanical and...

This article describes an optimal method (conflation) to consolidate data from different experiments, and illustrates the advantages of conflation by graphical examples involving gaussian input distributions, and by a concrete numerical example involving the values of lattice spacing of silicon crystals used in determination of the current values o...

Space radiation hazards are recognized as a key concern for human space flight. For long-term interplanetary missions, they constitute a potentially limiting factor since current protection limits for low-Earth orbit missions may be approached or even exceeded. In such a situation, an accurate risk assessment requires knowledge of equivalent doses...

We have measured the radiation transport and dose reduction properties of lunar soil with respect to selected heavy ion beams with charges and energies comparable to some components of the galactic cosmic radiation (GCR), using soil samples returned by the Apollo missions and several types of synthetic soil glasses and lunar soil simulants. The sui...

Recently, the Monte Carlo transport code HETC has been extended to include the interactions and transport of energetic heavy ions. Here, for the first time, we compare predictions of fragment production and energy loss with laboratory data measured at Brookhaven National Laboratory and at the National Institute of Radiological Sciences in Japan. Ve...

Only a modest shielding will be available to crew and components during future Exploration class missions, and the expense of transporting material to the moon will allow for little if any supplemental shielding material. An alternative is the essentially unlimited supply of lunar soil, if ways can be found to effectively use it. Measurements of se...

Space radiation hazards are recognized as a key concern for human space flight. For long-term interplanetary missions, they constitute a potentially limiting factor since current protection limits for low-Earth orbit missions may be approached or even exceeded. In such a situation, an accurate risk assessment requires knowledge of equivalent doses...

Ions of high atomic number and energy (HZE particles) pose a significant cancer risk to astronauts on prolonged space missions. On Earth, similar ions are being used for targeted cancer therapy. The properties of these particles can be drastically altered during passage through spacecraft shielding, therapy beam modulators, or the human body. Here,...

We present measurements and model calculations of fluence and linear energy transfer in water (LET infinity) obtained using Fe-56 beams with 1 GeV/amu kinetic energy incident on aluminum, polyethylene, PMMA, and lead targets. The measured spectra are compared to predictions of the PHITS model. The study is motivated by NASA's need to develop accura...

Mitigation of radiation exposures received by astronauts on deep-space missions must be considered in the design of future spacecraft. The galactic cosmic rays (GCR) include high-energy heavy ions, many of which have ranges that exceed the depth of shielding that can be launched in realistic scenarios. Some of these ions are highly ionizing (produc...

We have measured and calculated the radiation transport properties of lunar regolith with respect to galactic cosmic radiation and solar protons, in order to evaluate the utility of regolith as radiation shielding for humans on extended stays on the lunar surface.

Galactic and cosmic ray (GRC) radiation on the airless Moon will be life-threatening to astronauts. Experiments conducted with Apollo lunar soils have demonstrated that simulants are adequate substitutes for lunar samples in studies of radiation protection.

Charge-changing and fragment production cross sections at 0 degrees have been obtained for interactions of 290, 400, and 650 MeV/nucleon (40)Ar beams, 650 and 1000 MeV/nucleon (35)Cl beams, and a 1000 MeV/nucleon (48)Ti beam. Targets of C, CH(2), Al, Cu, Sn, and Pb were used. Using standard analysis methods, we obtained fragment cross sections for...

To meet the challenge of future deep space programs, an accurate and efficient engineering code for analyzing the shielding requirements against high-energy galactic heavy radiations is needed. In consequence, a new version of the HZETRN code capable of simulating high charge and energy (HZE) ions with either laboratory or space boundary conditions...

We present a summary of results from recent work in which we have compared nuclear fragmentation cross section data to predictions of the PHITS Monte Carlo simulation. The studies used beams of 12 C, 35 Cl, 40 Ar, 48 Ti, and 56 Fe at energies ranging from 290 MeV/nucleon to 1000 MeV/nucleon. Some of the data were obtained at the Brookhaven National...

Cosmic radiation shielding properties are important for spacecraft. Hydrogenous materials such as polyethylene have been shown effective against galactic cosmic rays (GCR) and solar energetic particles. Ultrahigh molecular weight polyethylene (UHMWPE) fibers have advanced mechanical and physical properties, which are very valuable for NASA missions...

To meet the challenge of future deep space programs an accurate and efficient engineering code for analyzing the shielding requirements against high-energy galactic heavy radiations is needed. Such engineering design codes require establishing validation processes using laboratory ion beams and space flight measurements in realistic geometries. In...

We have collected from the literature partial charge-changing cross sections for projectiles with charge 6⩽Z⩽26, energy ranging from 290 up to 2100 MeV/nucleon and interacting with several targets, in order to investigate weak and strong factorization properties. The same analysis methods as in our previous work have been applied to the data: we ha...

We are preparing to return humans to the Moon and setting the stage for exploration to Mars and beyond. However, it is unclear if long missions outside of Low-Earth Orbit (LEO) can be accomplished with acceptable risk. The central objective of our project, the Earth-Moon-Mars Radiation Exposure Module (EMMREM), is to develop and validate a numerica...

In planning for long-duration spaceflight, it will be important to accurately model the exposure of astronauts to heavy ions in the galactic cosmic rays (GCR). As part of an ongoing effort to improve heavy-ion transport codes that will be used in designing future spacecraft and habitats, fragmentation cross sections of 28Si have been measured using...

Naturally occurring radiation to which astronauts may be exposed come in three main forms: galactic cosmic rays (GCRs), charged particles accelerated to high energies by eruptive events at the Sun (solar energetic particles, or SEPs), and highly energetic particles trapped in the inner magnetospheres of the Earth and other magnetized planets.

The PHITS (Particle and Heavy Ion Transport System) code is a three-dimensional Monte Carlo code that is able to simulate the transport of nuclei and other particles in complicated geometries and calculate fluxes, doses, energy-deposition distributions and many other observables. Among its many possible fields of application, it can be used e.g. to...

The Zero Degree Detector (ZDD) is an instrument that has been used in accelerator expo- sures to measure the angular dependence of particles produced in heavy ion fragmentation experi- ments. The ZDD uses two identical layers of pixelated silicon detectors that make coincident meas- urements over the active area of the instrument. The angular distr...

Radiation risk management for human space missions depends on accurate modeling of high-energy heavy ion transport in matter. The process of nuclear fragmentation can play a key role in reducing both the physical dose and the biological effectiveness of the radiation encountered in deep space. Hydrogenous materials and light elements are expected t...

The design of future spacecraft such as the Crew Exploration Vehicle must take into account the radiation shielding properties of both the structural components as well as dedicated shielding materials. Since modest depths of shielding stop the vast majority of Solar Energetic Particles (SEP), the greater challenge is posed by the need to shield th...

A tissue-equivalent proportional counter (TEPC) has been used as a dosimeter in mixed radiation fields. Since it does not measure LET directly, the response function must be characterized in order to estimate quality factor and thus equivalent dose for the incident radiation. The objectives of this study were to measure the response of a spherical...

Measurements to characterize the shielding properties of the EMU space suit and a human phantom were performed using 155 and 250 MeV proton beams at the Loma Linda University Medical Center (LLUMC). The beams simulate radiation encountered in low-Earth orbit (LEO), where trapped protons having kinetic energies on the order of 100 MeV are abundant....

The ICCHIBAN InterComparison for Cosmic-rays with Heavy Ion Beams At NIRS project is an international collaboration established in order to intercompare detector response and intercalibrate space radiation instruments used for astronaut and cosmonaut dosimetry Over the past four years 20 laboratories in 12 nations have participated in eight ICCHIBA...

Projectile total and partial charge-changing cross sections have been measured for argon ions at 400 MeV/nucleon in carbon, aluminum, copper, tin and lead targets; cross sections for hydrogen were also obtained using a polyethylene target. The validity of weak and strong factorization properties has been investigated for partial charge-changing cro...

The design of future spacecraft such as the Crew Exploration Vehicle must take into account the radiation shielding properties of both the structural components as well as dedicated shielding materials. Since the vast majority of solar energetic particles (SEP) are stopped by modest depths of shielding, the far greater challenge is posed by the nee...

We report results for chromosomal aberrations in human peripheral blood lymphocytes after they were exposed to high-energy iron ions with or without shielding at the HIMAC, AGS and NSRL accelerators. Isolated lymphocytes were exposed to iron ions with energies between 200 and 5000 MeV/nucleon in the 0.1-1-Gy dose range. Shielding materials consiste...

Space radiation research is laying the groundwork for addressing the problem of radiation exposure to humans on extended space missions. This research relies heavily on investigations at ground-based proton and heavy ion accelerators. The interpretation of the data from these experiments depends sensitively on the details of how these heavily ioniz...

Radiation dosimetry for manned spaced missions depends on the ability to adequately describe the process of high-energy ion transport through many materials. Since the types of possible nuclear interactions are many and complex, transport models are used which depend upon a reliable source of experimental data. To expand the heavy ion database used...

A new version of the HZETRN code capable of validation with HZE ions in either the laboratory or the space environment is under development. The computational model consists of the lowest order asymptotic approximation followed by a Neumann series expansion with non-perturbative corrections. The physical description includes energy loss with stragg...

We have measured charged nuclear fragments produced by 1 GeV/nucleon 56 Fe ions interacting with aluminium, polyethylene and lead. These materials are relevant for assessment of radiation risk for manned space flight. The data will be presented in a form suitable for comparison with models of nuclear fragmentation and transport, including linear en...

The Green's function approach to ion transport greatly facilitates the modeling of laboratory radiation environments and allows for the direct testing of transport approximations of material transmission properties. This approach has been used successfully by radiation investigators at the NASA, Langley Research Center to construct simple solutions...

This report describes the highlights and progress made in a program of measurements studying radiation transport through materials of interest to NASA. All measurements were performed at accelerator facilities, primarily using GCR-like heavy-ion beams incident upon various elemental and composite targets. Both primary and secondary particles exitin...

ALTEA-MICE will supplement the ALTEA project on astronauts and provide information on the functional visual impairment possibly induced by heavy ions during prolonged operations in microgravity. Goals of ALTEA-MICE are: (1) to investigate the effects of heavy ions on the visual system of normal and mutant mice with retinal defects; (2) to define re...