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High resolution Cerenkov and range detectors for balloon-borne cosmic-ray experiment

A combination of an active Cerenkov detector and passive range detectors is proposed for the high resolution measurement of isotopic composition in the neighborhood of iron in the galactic cosmic rays. A large area (4,300 sq cm) Cerenkov counter and passive range detectors were tested. Tests with heavy ions (2.1 GeV/amu C-12, 289 MeV/amu Ar-40, and 594 MeV/amu Ne-20) revealed the spatial uniformity of response of the Cerenkov counter to be better than 1% peak-to-peak. Light collection efficiency is independent of projectile energy and incidence angle to within at least 0.5%. Passive Lexan track recorders to measure range in the presence of the nuclear interaction background which results from stopping particles through 0.9 interaction lengths of matter were also tested. It was found that nuclear interactions produce an effective range straggling distribution only approximately 75% wider than that expected from range straggling alone. The combination of these tested techniques makes possible high mass resolution in the neighborhood of iron.

Ahlen, S. P.↗

TREK - A cosmic-ray experiment on the Russian space station Mir

The goals of the TREK experiment, now in place on the Mir space station, are to resolve and measure the composition of both odd-Z and even-Z cosmic-ray nuclei up to uranium, to measure the isotopic composition of Fe-group nuclei, and to search for transuranic nuclei and exotic particles such as strangelets. To collect tracks of ultraheavy cosmic rays, exterior panels holding an array of BP-1 phosphate glass 1.2 sq m in area and 16 plates thick are now mounted outside the Kvant-2 module on Mir. Heaters and relays regulate the temperature of the glass at 25 +/- 5 C. The detectors will record about 1000 cosmic-ray tracks with Z greater than or equal to 50 during about 2.5 years. An interior panel consisting of an array 0.09 sq m in area and 32 plates thick and mounted on the inside wall of the Soyuz spacecraft will collect tracks of about 13,000 Fe and 500 Ni nuclei.

Price, P. B.↗

The Energetic Trans-Iron Cosmic-ray Experiment (ENTICE)

The ENTICE experiment is one of two instruments that comprise the "Orbiting Astrophysical Spectrometer in Space (OASIS)", which is presently undergoing a NASA "Astrophysics Strategic Mission Concept Study". ENTICE is designed to make high precision measurements of the abundances of individual elements from neon through the actinides and, in addition, will search for possible superheavy nuclei in the galactic cosmic rays. The ENTICE instrument utilizes silicon detectors, aerogel and acrylic Cherenkov counters, and a scintillating optical fiber hodoscope to measure the charge and energy of these ultra-heavy nuclei for energies greater than 0.5 GeV/nucleon. It is a large instrument consisting of four modules with a total effective geometrical factor of approx.20 sq m sr. Measurements made in space for a period of three years with ENTICE will enable us to determine if cosmic rays include a component of recently synthesized transuranic elements (Pu-94 and Cm-96), to measure the age of that component, and to test the model of the OB association origin of galactic cosmic rays. Additionally, these observations will enable us to study how diffusive shock acceleration of cosmic rays operates differently on interstellar grains and gas. Keywords: cosmic rays Galaxy:abundances

Binns, W. R.↗

Retinal changes in rats flown on Cosmos 936 - A cosmic ray experiment

Ten rats, five centrifuged during flight to simulate gravity and five stationary in flight and experiencing hypogravity, orbited the Earth. No differences were noted between flight-stationary and flight-centrifuged animals, but changes were seen between these two groups and ground controls. Morphological alterations were observed comparable to those in the experiment flown on Cosmos 782 and to the retinal cells exposed to high-energy particles at Berkeley. Affected cells in the outer nuclear layer showed swelling, clearing of cytoplasm, and disruption of the membranes. Tissue channels were again found, similar to those seen on 782. After space flight, preliminary data indicated an increase in cell size in montages of the nuclear layer of both groups of flight animals. This experiment shows that weightlessness and environmental conditions other than cosmic radiation do not contribute to the observed damage of retinal cells.

Philpott, D. E.↗

Apollo 17 lunar surface cosmic ray experiment - Measurement of heavy solar wind particles

During the Apollo 17 mission a series of metal foils and nuclear track detectors were exposed both in the sun and in the shade on the surface of the moon. Here we give the analysis of the mica detectors which were used to measure the flux of solar wind particles of Fe-group and heavier elements. These particles register as shallow pits after etching in hydrofluoric acid. Calibration experiments were performed to determine the registration properties of different ions and to simulate the lunar environment. We obtain an Fe-group flux of 39,000 per sec per sq cm, which together with the H flux measured on IMP-7 gives an Fe/H ratio of 0.000041. For elements with Z exceeding 45 we can set only an upper limit on the abundance, ruling out an overabundance of extremely heavy elements relative to iron by a factor of 4.

Zinner, E.↗

Particulate impacts on the UHCRE cosmic ray experiment teflon covers: The ESA programme

The optical scanning equipment at the University of Kent Unit for Space Science consists of a 102.5 by 42.5 cm computer controlled motorized stage which has a reproduction accuracy of 30 microns over the entire area. This is used with an optical microscope connected to two charge coupled device video cameras which can be used to obtain stereo color images of any features found. A coordinate system can be defined on each cover by means of two or more reference marks which allow a feature to be located using different equipment such as a scanning electron microscope, providing two known marks can be found. By using back illumination, penetrating features can be found automatically, and their sizes, circularity, and positions logged for later revisiting either on the optical system or using a scanning electron microscope.

Mcdonnell, J. A. M.↗

The Cosmic Ray Nuclei Experiment on the Spacelab-II mission

The Cosmic Ray Nuclei Experiment flown on the Spacelab-II mission was designed to measure the elemental composition of individual cosmic ray nuclei (Li to Ni) from 40 Gev/amu to several TeV/amu. The detector utilizes plastic scintillation counters for charge measurement, and gas Cerenkov and transition radiation detectors for energy measurements. The data analysis is in progress and results on the energy spectra are expected in the near future.

Grunsfeld, John Mace↗

Advanced Cosmic-Ray Composition Experiment for Space Station (ACCESS): ACCESS Accommodation Study Report

In 1994 NASA Administrator selected the first high-energy particle physics experiment for the Space Station, the Alpha Magnetic Spectrometer (AMS), to place a magnetic spectrometer in Earth orbit and search for cosmic antimatter. A natural consequence of this decision was that NASA would begin to explore cost-effective ways through which the design and implementation of AMS might benefit other promising payload experiments. The first such experiment to come forward was Advanced Cosmic-Ray Composition Experiment for Space Station (ACCESS) in 1996. It was proposed as a new mission concept in space physics to attach a cosmic-ray experiment of weight, volume, and geometry similar to the AMS on the International Space Station (ISS), and replace the latter as its successor when the AMS is returned to Earth. This was to be an extension of NASA's suborbital balloon program, with balloon payloads serving as the precursor flights and heritage for ACCESS. The balloon programs have always been a cost-effective NASA resource since the particle physics instrumentation for balloon and space applications are directly related. The next step was to expand the process, pooling together expertise from various NASA centers and universities while opening up definition of the ACCESS science goals to the international community through the standard practice of peer review. This process is still ongoing, and the accommodation study presented here will discuss the baseline definition of ACCESS as we understand it today.

Wilson, Thomas L.↗

A Cerenkov - Delta E/Delta X experiment for measuring cosmic-ray isotopes from neon through iron

Cosmic-ray isotope masses are measured in a balloon-borne cosmic-ray experiment. Two Cerenkov counters and an NaI scintillator stack are used to determine changes in energy and in the Lorentz factor for a traversing or stopping particle. The mass is defined at the ratio of the change in energy to the change in the Lorentz factor. For incident elements from neon through iron, mass resolution better than 0.3 a.m.u. is expected, with incident Lorentz gammas ranging from 2.4 to 3.1, depending on the element. The mass resolution is approximately 0.2 a.m.u., measured for Mn-55 ions having an incident Lorentz factor of 2.75.

Buffington, A.↗

Advanced Cosmic Ray Composition Experiment for Space Station (ACCESS)

In 1994 the first high-energy particle physics experiment for the Space Station, the Alpha Magnetic Spectrometer (AMS), was selected by NASA's Administrator as a joint collaboration with the U.S. Department of Energy (DOE). The AMS program was chartered to place a magnetic spectrometer in Earth orbit and search for cosmic antimatter. A natural consequence of this decision was that NASA would begin to explore cost-effective ways through which the design and implementation of AMS might benefit other promising payload experiments which were evolving from the Office of Space Science. The first such experiment to come forward was ACCESS in 1996. It was proposed as a new mission concept in space physics to place a cosmic-ray experiment of weight, volume, and geometry similar to the AMS on the ISS, and replace the latter as its successor when the AMS is returned to Earth. This was to be an extension of NASA's sub-orbital balloon program, with balloon payloads serving as the precursor flights and heritage for ACCESS. The balloon programs have always been a cost-effective NASA resource since the particle physics instrumentation for balloon and space applications are directly related. The next step was to expand the process, pooling together expertise from various NASA centers and universities while opening up definition of the ACCESS science goals to the international community through the standard practice of peer-review. This process is still on-going and the Accommodation Study presented here will discuss the baseline definition of ACCESS as we understand it today. Further detail on the history, scope, and background of the study is provided in Appendix A.

Wilson, Thomas L.↗

The Radar Echo Telescope for Cosmic Rays: Pathfinder experiment for a next-generation neutrino observatory

The Radar Echo Telescope for Cosmic Rays (RET-CR) is a recently funded experiment designed to detect the englacial cascade of a cosmic ray-initiated air shower via in-ice radar, toward the goal of a full-scale, next-generation experiment to detect ultrahigh energy neutrinos in polar ice. For cosmic rays with a primary energy greater than 10 PeV, roughly 10% of an air shower’s energy reaches the surface of a high elevation ice sheet (≳2 ˙km) concentrated into a radius of roughly 10 cm. This penetrating shower core creates an in-ice cascade orders of magnitude more dense than the preceding in-air cascade. Additionally, this dense cascade can be detected via the radar echo technique, where transmitted radio waves are reflected from the ionization deposit left in the wake of the cascade. RET-CR will test the radar echo method in nature, with the in-ice cascade of a cosmic ray-initiated air shower serving as a test beam. In this work, we present the projected event rate and sensitivity based upon a three part simulation using corsika, geant4, and radioscatter. RET-CR expects ~1 radar echo event per day.

79 ASTRONOMY AND ASTROPHYSICS↗

The observation program for the GSFC cosmic X-ray spectroscopy experiment

The cosmic X-ray spectroscopy experiment on OSO-8 will observe seven X-ray binary sources in its first six months of operation. If possible, each of these sources will be observed for one or more binary orbits so that the X-ray spectrum of each object can be observed through all phases of its orbit. For the two pulsing binaries, Her X-1 and Cen X-3, spectral variations over the pulse period will be studied. Simultaneous radio observations of Cyg X-1 and Cyg X-3 will search for any correlation between radio and X-ray emission. During the first year of operation, the detectors will observe over 50% of the known X-ray sources.

Becker, R. H.↗

Further analysis of a recent cosmic-ray antiproton experiment

Reference is made to the measurements of a cosmic ray antiproton flux at a few hundred MeV reported by Buffington et al. (1981), noting that one of the final background processes to be removed by the data analysis in that study was helium-induced events which satisfied the criteria for topology and timing. The response in the third scintillator S3 was used to identify and remove these events. For the top two scintillators S1 and S2, pulse size information was lost during the data-taking. A method is reported here for the partial retrieval of pulse size information for the scintillator S2. This is possible because a portion of this signal was subtracted from the Cerenkov response before trigger discrimination and data recording to remove scintillation from the Cerenkov response. For separating protons from more highly charged particles, the method is considered sufficient. It is pointed out that the sample of events identified as antiprotons, for which the method can be applied, has the expected unit charge in scintillator S2.

Buffington, A.↗