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Lindstrom, P. J.

Publications and source records attributed to Lindstrom, P. J..

16 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Stopping of relativistic heavy ions in various media

The residual ranges of (900 + or - 3)-MeV/amu gold nuclei accelerated at the Lawrence Berkeley Laboratory Bevalac have been measured in several different media. The energy of the beam of nuclei was measured directly using a new time-of-flight system. The ranges were measured by absorption in linear wedges of polyethylene, carbon, aluminum, copper, tin, and lead and in circular wedges of polystyrene, aluminum, and gold, and by total absorption in nuclear emulsion. The measured ranges were significantly different from those calculated from the best available theoretical estimates of the energy loss of highly charged nuclei. It is concluded that at present energy losses and residual ranges of relativistic heavy ions in an arbitrary medium cannot be predicted with better than an approximately 2 percent accuracy.

Waddington, C. J.↗
NASA NTRS1985

Implications of new measurements of O-16 + p + C-12,13, N-14,15 for the abundances of C, N isotopes at the cosmic ray source

The fragmentation of a 225 MeV/n O-16 beam was investigated at the Bevalac. Preliminary cross sections for mass = 13, 14, 15 fragments are used to constrain the nuclear excitation functions employed in galactic propagation calculations. Comparison to cosmic ray isotonic data at low energies shows that in the cosmic ray source C-13/C approximately 2% and N-14/0=3-6%. No source abundance of N-15 is required with the current experimental results.

Guzik, T. G.↗
NASA NTRS1980

A measurement of the isotopic composition of galactic cosmic ray carbon, nitrogen and oxygen

The paper reports the results of an investigation of the isotopic composition of galactic cosmic ray carbon, nitrogen and oxygen (80-230 MeV/amu) made using the U.C. Berkeley HKH instrument aboard the ISEE-3 spacecraft. The combination of high mass resolution and a large statistical sample makes possible a precise determination of the relative isotopic abundances for these elements. In local interplanetary space the following values are found: C-13/C = 0.067 + or - 0.008, N-15/N = 0.54 + or - 0.03, O-17/O less than 0.027, and O-18/O - 0.019 + or - 0.003.

Wiedenbeck, M. E.↗
NASA NTRS1975

Momentum distributions of isotopes produced by fragmentation of relativistic C-12 and O-16 projectiles

The fragment momentum distributions in the projectile rest frame are, typically, Gaussian shaped, narrow, consistent with isotropy, depend on fragment and projectile, and have no significant correlation with target mass or beam energy. The nuclear temperature is inferred from the momentum distributions of the fragments and is approximately equal to the projectile nuclear binding energy, indicative of small energy transfer between target and fragment.

Greiner, D. E.↗
NASA NTRS1975

Fragmentation of Ar-40 at 100 GeV/c

The delta Z is greater than or equal to 1 reaction cross section for 1.8 GeV/n Ar-40 have been measured on targets ranging from H to Pb. Comparing these cross sections with H-1, C-12, and O-16 reaction cross sections at relativistic energies yields a formula for nucleus-nucleus reaction cross sections.

Lindstrom, P. J.↗
NASA NTRS1975

Interactions of 2.1 GeV/n He-4, C-12, N-14 and O-16 nuclei in emulsion

The interaction mean-free-path lengths for He-4, C-12, N-14 and O-16 nuclei at 2.1 GeV/n have been measured in nuclear emulsion detectors. The angular distributions of Z equals 1 and 2 secondaries from the interactions of C, N and O beams are determined, and the topology of projectile fragmentation of these ions is examined.

Heckman, H. H.↗
NASA NTRS1974

Rigidity spectrum of z greater than or equal to 3 cosmic-ray nuclei in the range 4-285 GV and a search for cosmic antimatter

A measurement, using the magnetic emulsion spectrometer system, of the differential rigidity spectrum of Z greater than or equal to 3 nuclei of the galactic cosmic radiation is presented. The system was flown on Aug. 22, 1969, from Palestine, Texas. The instrument floated above 125,000 feet for eight hours. The data in the rigidity range 8-285 GV can be represented by a power-law spectrum in rigidity, J(rho) = A rho to the minus gamma power, with the exponent gamma = 2.6 plus or minus 0.10. The spectrum in the range 15-285 GV is also described by the same exponent, gamma = 2.6 plus or minus 0.25. The data below 8 GV cannot be described by the same power law without invoking solar modulation. A set of nonunique parameters for modulation are given. Upper limit for the fraction of antimatter in the rigidity range 4-125 GV is .005 with 95% confidence limit.

Golden, R. L.↗
NASA NTRS1974

Charge composition of cosmic rays between 4 and 100 GV

Balloon-flight measurements were used to determine ratios of cosmic-ray L nuclei (charge Z ranging from 3 to 5) to M nuclei (Z ranging from 6 to 8) and of VH nuclei (Z from 20 to 27) to M nuclei using a magnetic spectrometer. The purpose of the measurements was to establish whether both ratios vary with rigidity as this would provide evidence for more than one basic acceleration mechanism. The results provide no indication that the VH spectrum is steeper than the M spectrum.

Golden, R. L.↗
NASA NTRS1972

Fragmentation of N-14 nuclei at 29 GeV - Inclusive isotope spectra at 0 deg.

We report the first results of a Bevatron heavy-ion experiment on the inclusive spectra of isotopically identified nuclei 3(Z-range between 3 and 7), produced by the fragmentation of 29-GeV N-14 ions in carbon and hydrogen. The preliminary values of the partial differential cross sections at 0 deg give evidence that the modes of fragmentation of N-14 projectiles are independent of the target nucleus.

Heckman, H. H.↗
NASA NTRS1972

Response of trapped particles to a collapsing dipole moment.

Particle motion in the secularly varying geomagnetic field is investigated in terms of a dipolar magnetic field with decreasing magnetic moment M. For dM/dt equal to the rate of decay of the earth's dipole component, we find there is drift in B-L space, resulting in an inward drift of particles accompanied with increased energy and unidirectional intensity. Secular variation of the geomagnetic field appears to be a dominant mechanism for radial drift in the inner radiation belt.

Heckman, H. H.↗
NASA NTRS1971

Fragmentation of nitrogen-14 nuclei at 2.1 Gev per nucleon.

An experiment has been carried out at the bevatron on the nuclear fragmentation of nitrogen-14 ions at an energy of 2.1 billion electron volts (Gev) per nucleon. Because of the near equality of the velocities of the nitrogen-14 beam and the fragmentation products at an angle of 0 deg, we find it possible to identify the nuclear fragments isotopically.

Heckman, H. H.↗
NASA NTRS1968

B-L space and geomagnetic field models.

Geomagnetic field models compared in magnetic field strength-earth distance coordinates /B-L space/, noting geomagnetically trapped radiation flux ambiguities

Heckman, H. H.↗