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The goal of this white paper is to identify and describe promising key research goals to aid the theoretical characterization and observational detection of ionizing radiation from quiescent and flaring upper atmospheres of planet hosts as well as properties of stellar coronal mass ejections (CMEs) and stellar energetic particle (SEP) events.

Although not specifically designed for it, the Solar Isotope Spectrometer (SIS) on the Advanced Composition Explorer spacecraft is sensitive to particle anisotropies of heavy ions at energies of tens of MeV/nucleon. Using the arrival time of each particle (to the nearest second) and the trajectory measured with the instrument's position sensing detector, the arrival direction of each particle may be determined to ˜30° in azimuth about the spacecraft spin axis and to better than 1° in zenith angle from the axis. This allows the angular distribution of particles to be measured within the ˜145° wide field of view of the instrument, from which the intensities both along the field and perpendicular to it can usually be determined. We describe how anisotropies are obtained from SIS and present examples demonstrating some of the capabilities of SIS in studying anisotropies. With further analysis, SIS can contribute to studies exploring the dependence of particle angular distributions on energy and species.

The Isotope Magnet Experiment, ISOMAX, a balloon-borne superconducting magnet spectrometer was built with the capability to measure the isotopic composition of the light isotopes (3 ≤ Z ≤ 8) of the cosmic radiation up to 4 GeV/nucleon by using the β vs. rigidity technique with a mass resolution better than 0.25 amu, employing a combination of time-of-flight (TOF) system and silica-aerogel Cherenkov counters for the velocity determination. One of the primary scientific goals of ISOMAX was the accurate measurement of radioactive 10 Be with respect to its stable neighbor isotope 9 Be conveying information on the age of the cosmic rays in the galaxy. ISOMAX had its first flight on August 4-5, 1998, from Lynn Lake, Manitoba, Canada. It provided 13 h of data with a residual atmosphere of less than 5 g/cm^2 . This paper reports the results of the beryllium ratio 10 Be/9 Be = 0.195 ± 0.036 at the top of atmosphere in the energy range from 0.261 - 1.030 GeV/nucleon using the TOF in the 1998 flight. The high energy results of the beryllium ratio up to 2 GeV/nucleon in the Cherenkov regime as well as the lithium results in the TOF energy range are also reported in these proceedings.

A state-of-the-art time-of-flight (TOF) system has been developed for the ISOMAX balloon-borne cosmic ray instrument. ISOMAX was built to measure the isotopic composition of the light elements in the cosmic rays, (3

The Trans-Iron Galactic Element Recorder (TIGER) for the Ultra-Long Duration Balloon project Demo2000 (TD2K) is designed to measure the abundances of all elements in the Galactic Cosmic Rays (GCRs) with 26 ≤ Z ≤ 40 and energies above 300 MeV/nucleon. TD2K's flight is expected to approach 100 days in length. Launch will be from New Zealand in 2001. TD2K will have sufficiently good resolution to measure the individual abundances of the odd-Z elements between Z=26 and Z=40 for the first time. Measurements of odd-Z nuclei are important for distinguishing between the effects of first ionization potential and volatility in the injection process for ultraheavy GCRs, for models of nucleosynthesis, and constraining models of cosmic-ray propagation at short pathlengths. TD2K uses a combination of Cherenkov and scintillation counters to determine the atomic number and energy of incident cosmic rays, and a coded cintillating-fiber hodoscope for trajectory corrections. TD2K is an improved version of the TIGER instrument flown in 1997, results from which are reported at this conference (Sposato et al., 1999). We will present the status of the TD2K instrument and of the ULDB program as it affects the Demo 2000 flight.

TIGER is a balloon-borne cosmic-ray experiment designed to measure the elemental abundances of Galactic Cosmic Rays (GCRs) in the charge range 26

We report the results of an accelerator calibration of detectors planned for use in the ZIM experiment for ACCESS. The experiment utilizes silicon detectors to measure dE/dx, and aerogel and acrylic Cherenkov counters for velocity measurements. For a 79Au beam with energy 10.6 GeV/nucleon, we obtain resolution in charge for the silicon, acrylic Cherenkov, and aerogel Cherenkov of 0.20, 0.22, and 0.45 cu respectively.

The Isotope Magnet Experiment, (ISOMAX), is a balloon-borne superconducting magnetic spectrometer with a time-of-flight system and aerogel Cherenkov counters. Its purpose is to measure the isotopic composition of the light elements (3 < Z < 8) in the cosmic radiation. Particle mass is derived from a velocity vs. magnetic rigidity (momentum/charge) technique. The experiment had its first flight in August 1998. The precision magnetic spectrometer uses advanced drift-chamber tracking and a large, high-field, superconducting magnet. The drift-chamber system consists of three chambers with 24 layers of hexagonal drift cells (16 bending, 8 non-bending) and a vertical extent of 1.4 m. Pure CO2 gas is used. The magnet is a split-pair design with 79 cm diameter coils and a separation of 80 cm. During the 1998 flight, the central field was 0.8 T (60% of the full design field). Presented are results from flight data, for a range of incident particle Z, on the spatial resolution and efficiency of the tracking system, and on the maximum detectable rigidity (MDR) of the spectrometer. For in-flight data, spatial resolutions of 54 mm for Z=2 and 45 mm for Z=4 are obtained. An MDR of 970 GV/c is achieved for Z=2.

We describe the science motivation and development of a pair production telescope for medium-energy gamma-ray polarimetry. Our instrument concept, the Advanced Energetic Pair Telescope (AdEPT), takes advantage of the Three-Dimensional Track Imager, a low-density gaseous time projection chamber, to achieve angular resolution within a factor of two of the pair production kinematics limit (~0.6 deg at 70 MeV), continuum sensitivity comparable with the Fermi-LAT front detector (, Version to be published in Astroparticle Physics, 32 pages, 11 figures