Search NASA⌕ Search

Engineering topics

Ormes, J. F.

Publications and source records attributed to Ormes, J. F..

At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Energy Spectra of Cosmic Ray Nuclei to Above 100 Gev/nucleon

The chemical composition cosmic rays as a function of energy in the range of a few GeV/nucleon to some hundreds of GeV/nucleon for boron through iron are presented. The experiment combined an ionization spectrometer and a gas Cherenkov counter, which was flown on a balloon, to perform two different and independent energy measurements. The experimental apparatus is described in detail. The energy dependence of the cosmic ray escape length for boron and iron is reported and predicted changes in the energy dependence of the ratios of primary nuclei 0/C and iron/C+0 are discussed.

Simon, M.↗
NASA NTRS1979

An instrument to measure the spectrum of cosmic ray iron and other nuclei to above 100 GeV/nucleon

A balloon-borne instrument system for the study of cosmic ray composition in the energy region beyond 100 GeV/nucleon is described. The large area detector incorporates an ionization spectrometer or calorimeter to determine the energy of the incident particles which is calibrated in flight by a gas Cerenkov counter filled with freon 12 at 20 psi. Calibration of calorimeter response indicates that the effects of ionization energy loss and nucleon fragmentation are correctly accounted for in a Monte Carlo simulation. A charge measuring module consisting of five scintillators and a lucite Cerenkov counter is used to determine the charge and position of the incoming particles. A spatial resolution of 5 to 10 cm has been obtained by using the ratios of pulse heights in different photomultiplier tubes aimed at the same scintillators within the module. The detector represents the heaviest cosmic ray experiment that can be flown over 30 km using the dynamic launching technique commonly employed.

Arens, J. F.↗
NASA NTRS1978

An instrument to measure the spectrum of cosmic ray iron and other nuclei to above 100 GeV-nucleon

A balloon-borne detector system for extending the study of cosmic ray composition to the energy region beyond 100 GeV/nucleon is described. The instrument incorporates an ionization calorimeter and a gas Cherenkov counter filled with freon for the determination of energies, and a charge module, consisting of scintillation and a lucite Cherenkov counter, for determining the charge of the incoming particle. The scintillators were utilized to determine the position of the incoming particle in addition to its charge. The characteristics of these detectors with respect to resolution, and the methods employed in laboratory calibration, cross-checks with flight data and actual performance in the flights are described in detail. Monte Carlo simulation of the ionization calorimeter and comparison of the response of the calorimeter and gas Cherenkov counter for complex nuclei was used to convert the observed calorimeter signal to absolute energy in a consistent manner.

Arens, J. F.↗
NASA NTRS1978

High energy cosmic ray iron spectrum experiment

An instrument containing a gas Cerenkov counter and an iron ionization spectrometer was constructed in order to measure the cosmic-ray iron spectrum to 300 GeV/nucleon. Trajectories of particles were determined by entopistic or position-determining scintillator systems. The geometric factors with and without the gas Cerenkov counter were 0.3 and 0.6 sq m-ster, respectively. The instrument was successfully flown in June 1976 without the spectrometer and in October 1976 with the spectrometer from Palestine, Texas. The June flight yielded 14.5 h of data; the October flight, 25 h.

Arens, J. F.↗
NASA NTRS1977

Energy spectra of cosmic ray nuclei - Z of 4 to 26 and E of 0.3 to 2 GeV/amu

The differential kinetic-energy spectra of cosmic-ray nuclei in the charge range from 4 to 28 are determined using data obtained from a high-altitude balloonborne detector. The data are derived from the response of an acrylic plastic Cerenkov counter and cover the kinetic-energy range from 400 to 2100 MeV/amu. A Cerenkov pulse-height histogram is obtained for each charge, and the kinetic-energy spectra are derived by means of a formal mathematical deconvolution of these histograms. Results of the deconvolution calculation extrapolated to the top of the atmosphere are presented for the most abundant nuclei; it is found that the spectra are not amenable to representation by spectral indices, so the relative spectra of the different elements are compared by evaluating the charge ratios as a function of energy. The results show that secondary/primary ratios decrease with increasing energy, while primary/primary ratios are constant for Z of 6 to 10 and 14 to 26 but vary for Z of 10 to 14. It is concluded that the data seem to indicate more than one cosmic-ray source region.

Maehl, R. C.↗
NASA NTRS1977

Be-10 abundance and the age of cosmic rays - A balloon measurement

A balloon-borne payload was launched from Thompson, Canada, on August 15, 1973. The float depth averaged 4.5 g/sq cm of residual atmosphere, and the experiment live time was 31,500 sec. A total-energy-versus-range technique was used in the measurements. Preliminary results from this experiment have been given by Hagen et al. (1975). The final results are reported along with a detailed description of the analysis techniques. Information is provided concerning improved atmospheric and energy corrections, an updated estimation of the modulation effects, and a revised lifetime estimate.

Hagen, F. A.↗
NASA NTRS1976

Energy spectra of cosmic ray nuclei: 4z26 and .3E2 GeV/amu

Energy spectra of cosmic ray nuclei in the charge range 5 is less than or equal to z less than or equal to 26 have been derived from the response of an acrylic plastic Cerenkov detector. Data were obtained using a balloon borne detector and cover the energy range 320 is approximately less than e approximately less than 2200 MeV. amu. Spectra are derived from a formal deconvolution using the method of Lezniak (1975). Relative spectra of different elements are compared by observing charge ratios. Secondary primary ratios are observed to decrease with increasing energy, consistent with the effect previously observed at higher energy. Primary to primary ratios are constant for 6 is less than or equal to z less than or equal to 26 and 14 is less than or equal to z less than or equal to 26 but vary for 10 is less than or equal to z less than or equal to 14. This data is found to be consistent with existing data where comparable and lends strong support ot the idea of two separate source populations contributing to the cosmic ray composition.

Maehl, R. C.↗
NASA NTRS1976

The isotopic composition of cosmic rays with Z between 5 and 26

Results are reported for a high-altitude balloon flight which measured the isotopic composition of cosmic rays by using a Cerenkov-range technique to determine the masses of arriving cosmic rays with charges between 5 and 26 for kinetic energies around 450 MeV/amu. Event-selection criteria are discussed, and the mass-determination technique is outlined. Some of the mass histograms resulting from the analysis are presented along with the mean masses calculated from the data, and the derived isotopic compositions. It is found that: (1) C, N, and O are consistent with pure C-12, N-14, and O-16 sources; (2) Mg seems to require some neutron-rich component at the source; (3) Ne appears to require a source isotopic composition that is even more neutron-rich than the universal abundances; and (4) the source may be somewhat enriched in Fe-54. It is suggested that the fundamental nuclear physics which governed the synthesis of solar-system material may also be responsible for cosmic rays, implying that the solar system is probably an average sample of galactic matter.

Fisher, A. J.↗
NASA NTRS1975

Neutron-rich isotopes of cosmic rays with Z between 9 and 16

Data are reported on the isotopic composition of cosmic rays with charges between 9 and 16 at a temperature of 450 MeV per amu. The data show the presence of a considerable neutron-rich component of Mg and Ne, the measured mean masses being 24.3 plus or minus 0.1 and 20.8 plus or minus 0.1, respectively. Coupled with a calculation of the evolution of cosmic-ray isotopic abundances during propagation, these masses indicate that there is probably some neutron-rich material in this charge range at the cosmic-ray source. To explain the Ne mass requires more neutron-rich Ne at the source than is observed in solar-system material. This result is discussed in light of recent theories of nucleosynthesis and cosmic-ray propagation.

Maehl, R. C.↗
NASA NTRS1975

The isotopic composition of cosmic rays with 5 is less than or equal to z which is less than or equal to 26

Results obtained from a high altitude balloon flight from Thompson, Canada in August, 1973 are reported. The instrument consisted of a spark chamber, a Lucite Gerenkov counter and thirteen layers of scintillators. For heavy particles the Cerenkov-range method of analysis was used to determine the mass of particles energetic enough to produce a Cerenkov signal and then stop in the layered scintillators. The data appear to be consistent with current cosmic-ray propagation models. Using a simple exponential path length propagation model this data is extrapolated to the cosmic-ray source and some implications of the data are discussed as to the nature of the source.

Fisher, A. J.↗
NASA NTRS1975

Cosmic-ray composition measurements with high-energy ionization spectrometers

Element abundances of cosmic rays for elements Li through Si with energy above 0.8 GeV/amu were measured on a balloon-borne instrument containing a total absorption ionization spectrometer. Statistical techniques were used to analyze the five measurements of each particle to determine its charge and energy. The technique allows a determination of systematic errors to be made. Corrections for Landau fluctuations, spark-chamber inefficiency, and background particles were included. Comparison with other published results is made. There are differences in the shapes of the differential spectra determined from measurements using different techniques, and our intensities still lie somewhat below those of other workers.

Arens, J. F.↗
NASA NTRS1975

Adaptation of an existing cosmic ray ionization spectrometer experiment to Spacelab

This paper examines the technique of adapting an existing experiment to a Shuttle sortie mission. A sample cosmic-ray balloon experiment was studied to determine the feasibility of this cost-saving technique, which is applicable to a large spectrum of existing experiments, and to determine the programmatic impact and key problems. The main areas investigated include the determination of required modifications, steps in integration to the Spacelab/Shuttle, and the impact on orbital support and operations. One of the main problems in equipment adaptation is the acoustical loading during Shuttle boost; an environmental cover design presented herein shows a potential method to attain the required acoustic attenuation.

Alvarado, U. R.↗
NASA NTRS1975

A balloon measurement of the cosmic ray element abundances

The experiment described was flown from Thompson, Canada in August, 1973 to measure the cosmic ray element abundances in the atmosphere. All particles used in the analysis, including approximately 25,000 oxygen and 1600 iron nuclei, had sufficient energy at the top of the atmosphere to trigger the Cerenkov counter. Nuclei between beryllium and nickel were identified, using two plastic scintillators and an acrylic plastic Cerenkov counter. The relative composition and fluxes are determined. Agreement with earlier measurements in the atmosphere is within 5%; however, larger differences appear in composition extrapolated to the top of the atmosphere. In particular, the nitrogen abundance is almost 20% higher and the iron abundance is 20% lower than the generally accepted values.

Ormes, J. F.↗
NASA NTRS1975

Astrophysical implications of the isotopic composition of cosmic rays

This paper considers some of the astrophysical consequences of recent cosmic-ray isotope measurements in the charge range between 4 and 26 for energies of 200 to 600 MeV/amu. Using a simple exponential path-length propagation model, the isotopic and chemical compositions are extrapolated observed back to the cosmic-ray source. With the possible exception of neon, all the results are consistent with the current understanding of cosmic-ray propagation and source composition. Some implications of the isotopic data as to the nature of the source are discussed.

Maehl, R.↗
NASA NTRS1975

A Cerenkov-Range analysis of the isotopic composition of cosmic rays with Z from 6 to 26

High-altitude balloon data on the isotopic composition of heavy cosmic rays are reported. The experiment used a Cerenkov detector, arrays of scintillators, and a digitized wire spark chamber. Peaks assigned to the mono-isotopic elements F and Na indicate that an absolute mass scale can be derived from the data. Even-Z elements in the Z range from 12 through 16 are represented mainly by alpha-particle nuclei. Neutron-rich components dominate in the case of neon present. Mass histograms are plotted for C, O, N, Ne, Mg, and Fe.

Fisher, A. J.↗
NASA NTRS1974

Cosmic ray composition measurements and high energy ionization spectrometers

Element abundances of cosmic rays Li through Si with energy above 0.8 GeV/amu were measured on a balloon borne instrument containing a total absorption ionization spectrometer. Statistical techniques were used to analyze the five measurements of each particle to determine its charge and energy. The technique allows a determination of systematic errors to be made. Corrections for Landau fluctuations, spark chamber inefficiency, and background particles were included. Comparison with other published results is made. Differences in the shape of the spectrum determined from measurements of different workers indicate that the absolute intensity is still known to only plus or minus 15% between 2 and 10 GV/c rigidity.

Arens, J. F.↗
NASA NTRS1974

An interpretation of the carbon-oxygen to iron ratio

Data from recent measurements on the composition of primary cosmic rays above 1 GeV/nucleon are critically reviewed for information pertaining to selection of suitable energy-dependent composition models. Areas where crucial experimental information may result in selection of a suitable model are pointed out. In particular, the study of the energy distribution of VVH nuclei, and the derivation of more accurate energy spectra of 10 less than or equal to Z less than or equal to 14, 15 less than or equal to Z less than or equal to 23 and Z greater than 24 would contribute to discriminate between models which rely on interstellar propagation and those that ascribe a different source mechanism for Fe group nuclei.

Balasubrahmanyan, V. K.↗