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Sample records for ray heavy nuclei

  1. Propagation of heavy cosmic-ray nuclei

    NASA Technical Reports Server (NTRS)

    Letaw, J. R.; Silberberg, R.; Tsao, C. H.

    1984-01-01

    Techniques for modeling the propagation of heavy cosmic-ray nuclei, and the required atomic and nuclear data, are assembled in this paper. Emphasis is on understanding nuclear composition in the charge range Z = 3-83. Details of the application of 'matrix methods' above a few hundred MeV/nucleon, a new treatment of electron capture decay, and a new table of cosmic ray-stable isotopes are presented. Computation of nuclear fragmentation cross sections, stopping power, and electron stripping and attachment are briefly reviewed.

  2. The survival of heavy nuclei in cosmic ray source environments

    NASA Technical Reports Server (NTRS)

    Balasubrahmanyan, V. K.

    1972-01-01

    Results from the Goddard balloon spectrometer and the results reported by Soviet scientists using the Proton series of satellites are summarized. The important experimental results from the balloon spectrometer experiment are as follows: (1) On a total-energy scale, protons constitute only a minor proportion of the cosmic rays, only 20 percent. The rest of the cosmic rays are complex nuclei. (2) All the nuclei have the same power low spectrum in total energy and so the composition seems to be independent of energy.

  3. Measurement of heavy cosmic-ray nuclei on LDEF (M0002-2)

    NASA Technical Reports Server (NTRS)

    Beaujean, R.; Enge, W.; Siegmon, G.

    1984-01-01

    The objective of this experiment is to measure the elemental and isotopic abundamces of heavy cosmic-ray nuclei with nuclear charge Z equal to or greater than 3. The chemical and energy spectra will be measured for particles that have energies in the range from 20 to 1000 MeV per atomic mass unit. Two points of great interest are geomagneticaly forbidden cosmic-ray particles and heavy ions of the trapped radiation.

  4. A high-resolution study of ultra-heavy cosmic-ray nuclei (A0178)

    NASA Technical Reports Server (NTRS)

    Osullivan, D.; Thompson, A.; Oceallaigh, C.; Domingo, V.; Wenzel, K. P.

    1984-01-01

    The main objective of the experiment is a detailed study of the charge spectra of ultraheavy cosmic-ray nuclei from zinc (Z = 30) to uranium (Z = 92) and beyond using solid-state track detectors. Special emphasis will be placed on the relative abundances in the region Z or - 65, which is thought to be dominated by r-process nucleosynthesis. Subsidiary objectives include the study of the cosmic-ray transiron spectrum a search for the postulated long-lived superheavy (SH) nuclei (Z or = 110), such as (110) SH294, in the contemporary cosmic radiation. The motivation behind the search for super-heavy nuclei is based on predicted half-lives that are short compared to the age of the Earth but long compared to the age of cosmic rays. The detection of such nuclei would have far-reaching consequences for nuclear structure theory. The sample of ultraheavy nuclei obtained in this experiment will provide unique opportunities for many tests concerning element nucleosynthesis, cosmic-ray acceleration, and cosmic-ray propagation.

  5. Ultrahigh energy cosmic rays as heavy nuclei from cluster accretion shocks

    NASA Astrophysics Data System (ADS)

    Inoue, Susumu; Sigl, Günter; Miniati, Francesco; et al.

    Large-scale accretion shocks around massive clusters of galaxies, generically expected in hierarchical scenarios of cosmological structure formation, are shown to be plausible sources of the observed ultrahigh energy cosmic rays (UHECRs) by accelerating a mixture of heavy nuclei including the iron group elements. Current observations can be explained if the source composition at injection for the heavier nuclei is somewhat enhanced from simple expectations for the accreting gas. The proposed picture should be clearly testable by current and upcoming facilities in the near future through characteristic features in the UHECR spectrum, composition and anisotropy, in particular the rapid increase of the average mass composition with energy from 1019 to 1020 eV. The associated X-ray and gamma-ray signatures are also briefly discussed.

  6. Studies of the ionization states of solar and galactic cosmic ray heavy nuclei

    NASA Technical Reports Server (NTRS)

    Biswas, S.

    1982-01-01

    Enhancement of abundances of heavy nuclei (e.g., Mg, Si, and Fe) at low energies relative to solar photospheric abundances and anomalously high abundances of iron relative to oxygen nuclei at low energies were recently discovered in solar energetic particles studied at low energy. These phenomena are not understood at present. The proposed experiment is designed to study the recently discovered anomalous component of low energy galactic cosmic ray ions of C, N, O, Ne, and Ca to Fe of energy 5- to 10-million electron volts per atomic mass unit in regard to their ionization states, composition, and intensity, and to study the ionization states of heavy elements from oxygen to iron in energetic solar particles emitted during flare events. The same detector system will serve for both studies, with the second objective being given priority if there are any solar particle events during the mission.

  7. Frequency of light-flashes induced by Cerenkov radiation from heavy cosmic-ray nuclei

    NASA Technical Reports Server (NTRS)

    Madey, R.; Mcnulty, P. J.

    1972-01-01

    The expected frequency was calculated for light flashes induced in the dark-adapted eye by Cerenkov radiation from the flux of heavy nuclei that exists in space beyond the geomagnetic field. The expected frequency of light flashes depends on the threshold number of photons that must be absorbed in a rod cluster. The results of the calculation are presented as a curve of the mean frequency of light flashes versus the threshold number of absorbed photons. The results are not sensitive to variations in the path length from 5 to 15 grams per square centimeter of water-equivalent before the nucleus reaches the retina. Calculations were based on the fluxes and energy spectra of galactic cosmic ray nuclei of helium to iron, measured at a time of minimum solar modulation. The expected light flash frequencies induced by Cerenkov radiation are consistent with the frequencies reported by the astronauts on Apollo missions 11 through 14.

  8. Super-heavy nuclei

    NASA Astrophysics Data System (ADS)

    Hofmann, Sigurd

    2015-11-01

    Scientifically based searches for elements beyond uranium started after the discovery of the neutron. Neutrons captured by uranium nuclei and subsequent {β }- decay, similarly as most of the elements were produced in nature, was the successful method applied. However, as a first result, Hahn and Strassmann discovered nuclear fission indicating a limit for the existence of nuclei at an increasing number of protons. Eventually, the nuclear shell model allowed for a more accurate calculation of binding energies, half-lives and decay modes of the heaviest nuclei. Theoreticians predicted a region of increased stability at proton number Z = 126, later shifted to 114, and neutron number N = 184. These nuclei receive their stability from closed shells for the protons and neutrons. Later, increased stability was also predicted for deformed nuclei at Z = 108 and N = 162. In this review I will report on experimental work performed on research to produce and identify these super-heavy nuclei (SHN). Intensive heavy ion beams, sophisticated target technology, efficient electromagnetic ion separators, and sensitive detector arrays were the prerequisites for discovery of 12 new elements during the last 40 years. The results are described and compared with theoretical predictions and interpretations. An outlook is given on further improvement of experimental facilities which will be needed for exploration of the extension and structure of the island of SHN, in particular for searching for isotopes with longer half-lives predicted to be located in the south east of the island, for new elements, and last not least, for surprises which, naturally, emerge unexpectedly.

  9. Photodisintegrated gamma rays and neutrinos from heavy nuclei in the gamma-ray burst jet of GRB 130427A

    NASA Astrophysics Data System (ADS)

    Joshi, Jagdish C.; Razzaque, Soebur; Moharana, Reetanjali

    2016-05-01

    Detection of ˜0.1-70 GeV prompt γ-ray emission from the exceptionally bright gamma-ray burst (GRB) 130427A by the Fermi-Large Area Telescope provides an opportunity to explore the physical processes of GeV γ-ray emission from the GRB jets. In this work, we discuss interactions of Iron and Oxygen nuclei with observed keV-MeV photons in the jet of GRB 130427A in order to explain an additional, hard spectral component observed during 11.5-33 s after trigger. The photodisintegration time-scale for Iron nuclei is comparable to or shorter than this duration. We find that γ rays resulting from the Iron nuclei disintegration can account for the hard power-law component of the spectra in the ˜1-70 GeV range, before the γγ → e± pair production with low-energy photons severely attenuates emission of higher energy photons. Electron antineutrinos from the secondary neutron decay, on the other hand, can be emitted with energies up to ˜2 TeV. The flux of these neutrinos is low and consistent with non-detection of GRB 130427A by the IceCube Neutrino Observatory. The required total energy in the Iron nuclei for this hadronic model for GeV emission is ≲10 times the observed total energy released in the prompt keV-MeV emission.

  10. Detection of the isotopes of heavy cosmic ray nuclei. [by particle counter telescope

    NASA Technical Reports Server (NTRS)

    Gilman, C. M.; Waddington, C. J.

    1975-01-01

    A counter telescope designed to detect and resolve the isotopic composition of cosmic ray nuclei heavier than neon is being prepared. The telescope consists of a rather conventional charge measuring array using two scintillator elements and two solid Cerenkov radiators of differing refractive index. The mass measurement is obtained by combining the velocity information from one or both of the Cerenkov radiators operating near their threshold with residual range measured in a block of nuclear emulsion. Path length corrections and particle location in the emulsions is provided by a spark chamber fired in coincidence with potentially suitable particles. The telescope has a geometry factor of 530 sq cm sr roughly. It should be able to resolve the isotopes of iron over the energy range of 300 to 720 Mev/n and those of neon over 300 to 400 MeV/n. The expected response and characteristics of the telescope are described in detail and the sensitivity to rare isotopes discussed.

  11. LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04 EL-1994-00089 LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04 The flight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on the center clamp blocks of the experiment trays left flange and lower flange appear to be discolored by a dark brown stain. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays upper flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal cover appears to be specular and

  12. LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B05

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B05 EL-1994-00088 LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B05 The flight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on the center clamp block of the experiment trays lower flange appears to be discolored by a dark brown stain. The tray flanges also appear to be discolored but with a lighter stain. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays upper flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF

  13. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04 EL-1994-00391 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC prior to removal of the experiment tray from the LDEF. The paint dots on the experiment tray clamp blocks, originally white, appearsDE:to be discolored by a brown stain. The experiment tray flanges also appear to be coated but with a lighter colored stain. The UHCRE detectors were contained in 16 peripheral LDEF trays with at leastDE:one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The

  14. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D05

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D05 EL-1994-00311 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D05 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after removal of the experiment tray from the LDEF. The experiment tray flanges appear discolored by a brown stain. Outlines of experiment tray clamp blocks are clearly visible on the upper and lower tray flanges. The experiment tray holding fixture hardware covers the clamp block areas on the end flanges. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the

  15. LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C08

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C08 EL-1994-00661 LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C08 The flight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on the center clamp block of the experiment trays upper flange and the right end of the experiment trays lower flange appear to be slightly discolored. The tray flanges appear to be discolored by a light brown stain and the ground strap located in the center of the lower flange appears intact but a much darker copper color than in the prelaunch photograph. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored

  16. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E02

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E02 EL-1994-00385 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E02 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC prior to removal of the experiment tray from the LDEF. The white paint dot on the experiment tray clamp blocks located at the center of the trays lower and left flanges and at the right end of the trays upper flange appear to be discolored by a brown stain. The experiment tray flanges also appear to be coated but with a lighter colored stain. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an

  17. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04 EL-1994-00272 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after the experiment tray was removed from the LDEF and the silvered TEFLON® thermal cover removed. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. A copper coated pressure sensitive tape was used to provide an electrical ground strap between the thermal cover and the LDEF structure. All experiment hardware appears to be in prelaunch condition and securely in place. The three cylindrical pressure vessels containing the experiment detectors are shown mounted in the experiment tray with the frame for mounting the

  18. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B05

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B05 EL-1994-00184 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B05 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC prior to removal of the experiment tray from the LDEF. The paint dots on the experiment tray clamp blocks, originally white, appears to be discolored by a brown stain. The experiment tray flanges also appear to be coated but with a lighter colored stain. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE

  19. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C06

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C06 EL-1994-00206 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C06 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after removal of the experiment tray from the LDEF. The experiment tray flanges appear discolored by a light brown stain. Outlines of experiment tray clamp blocks are clearly visible on the lower tray flanges.The experiment tray holding fixture hardware covers the clamp block areas on the end flanges. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays upper flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments

  20. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A02

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A02 EL-1994-00387 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A02 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC prior to removal of the experiment tray from the LDEF. The white paint dot on the experiment tray clamp blocks located at the center of the trays upper and right flanges and at the left end of the trays lower flange appear to be discolored by a brown stain. The experiment tray flanges also appear to be coated but with a lighter colored stain. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar with a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an

  1. LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E02

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E02 EL-1994-00131 LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E02 The flight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on the center clamp blocks of the experiment trays left flange and lower flange appear to be slightly discolored. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal cover appears to be intact with out visible

  2. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C05

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C05 EL-1994-00205 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C05 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after removal of the experiment tray from the LDEF. The experiment tray flanges appear discolored by a brown stain that provides outlines of the experiment tray clamp blocks that are clearly visible on the upper and lower tray flanges.The experiment tray holding fixture hardware covers the clamp block areas on the end flanges. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground

  3. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A10

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A10 EL-1994-00122 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A10 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in the Orbiter Processing Facility (OPF) at KSC during removal of the LDEF from the Orbiters cargo bay. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays upper flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal covers surface appears to have changed from specular to opaque (glossy white) with many black dots of various sizes that appear to be impact craters. An impact

  4. LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E10

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E10 EL-1994-00019 LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E10 The flight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on the center clamp blocks of the experiment trays left flange and lower flange appear to be slightly discolored. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal covers surface appears to have changed from

  5. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E10

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E10 EL-1994-00162 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E10 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in the Orbiter Processing Facility during removal of the LDEF from the Orbiter's payload bay. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal covers surface appears to have changed from specular to opaque with numerous black dots of various sizes that appear to be impact craters. Many of the craters appear to have

  6. Cosmic-ray slowing down in molecular clouds: Effects of heavy nuclei

    NASA Astrophysics Data System (ADS)

    Chabot, Marin

    2016-01-01

    Context. A cosmic ray (CR) spectrum propagated through ISM contains very few low-energy (<100 MeV) particles. Recently, a local CR spectrum, with strong low energy components, has been proposed to be responsible for the over production of H3+ molecule in some molecular clouds. Aims: We aim to explore the effects of the chemical composition of low-energy cosmic rays (CRs) when they slow down in dense molecular clouds without magnetic fields. We considered both ionization and solid material processing rates. Methods: We used galatic CR chemical composition from proton to iron. We propagated two types of CR spectra through a cloud made of H2: those CR spectra with different contents of low energy CRs and those assumed to be initially identical for all CR species. The stopping and range of ions in matter (SRIM) package provided the necessary stopping powers. The ionization rates were computed with cross sections from recent semi-empirical laws, while effective cross sections were parametrized for solid processing rates using a power law of the stopping power (power 1 to 2). Results: The relative contribution to the cloud ionization of proton and heavy CRs was found identical everywhere in the irradiated cloud, no matter which CR spectrum we used. As compared to classical calculations, using protons and high-energy behaviour of ionization processes (Z2 scaling), we reduced absolute values of ionization rates by few a tens of percents but only in the case of spectrum with a high content of low-energy CRs. We found, using the same CR spectrum, the solid material processing rates to be reduced between the outer and inner part of thick cloud by a factor 10 (as in case of the ionization rates) or by a factor 100, depending on the type of process.

  7. Proton Distribution in Heavy Nuclei

    DOE R&D Accomplishments Database

    Johnson, M. H; Teller, E.

    1953-11-13

    It is reasoned that, from considerations connected with beta-decay stability and Coulomb repulsion forces, a neutron excess is developed on the surface of heavy nuclei. Several consequences of this qualitative analysis in nucleon interactions are briefly noted. (K.S.)

  8. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B07

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B07 EL-1994-00312 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B07 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after removal of the experiment tray from the LDEF. The outline of the experiment tray clamp blocks is clearly visible on the upper tray flange and to a lesser extent on the lower flange. The holding fixture hardware covers the clamp block areas on the end flanges. The prelaunch photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC prior to installation of the experiment tray on the LDEF. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the

  9. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray F04

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray F04 EL-1994-00171 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray F04 The postflight photograph was taken in the SAEF II at KSC after the experiment was removed from the LDEF. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal cover appears to be specular and intact. The circular damaged locations that appeared to to be impact points in the flight photograph are not as apparent in the reflections and is less taut cover. The wrinkled spots on the thermal cover are areas

  10. The Heavy Nuclei Explorer (HNX) Mission

    NASA Technical Reports Server (NTRS)

    Binns, W. R.

    2001-01-01

    The Heavy Nuclei eXplorer (HNX) mission was recently selected by NASA for a Small Explorer (SMEX) Mission Concept Study to begin in 2001. The primary scientific objectives of HNX are to measure the age of the galactic cosmic rays (GCR) since nucleosynthesis, determine the injection mechanism for the GCR accelerator (Volatility or FIP), and study the mix of nucleosynthetic processes that contribute to the source of GCRs. The experimental goal of HNX is to measure the elemental abundances of all individual stable nuclei from neon through the actinides and possibly beyond. HNX is composed of two instruments: ECCO, which measures elemental abundances of nuclei with Z(sup 3)72, and ENTICE, which measures elemental abundances of nuclei with 10(f)Z(f)82. We will discuss the mission and the science that can be addressed by HNX.

  11. LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A10

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A10 EL-1994-00018 LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A10 The flight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on the clamp blocks located at the center of the experiment trays upper and right flanges appear to be in prelaunch condition while the one located at the left end of the trays lower flange appears slightly discolored. Note the dark brown stain on the LDEF structure adjacent to the edge of the black thermal cover. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays right flange is

  12. LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B07

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B07 EL-1994-00087 LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B07 The flight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on the center clamp blocks of the experiment trays left flange and lower flange appear to be slightly discolored but the paint dot on the clamp block located at the right end of the upper flange appears to be stained less. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the

  13. LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D01

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D01 EL-1994-00134 LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D01 The flight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The paint dot , originally white, on the experiment tray clamp block located at the center of the trays lower flange appears to be discolored by a brown stain. The experiment trays lower flange also appears to be coated but with a much lighter stain. The paint dots on clamp blocks at each end of the trays upper flange appear to be discolored very little. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the

  14. LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D07

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D07 EL-1994-00062 LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D07 The flight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dot on the center clamp block of the experiment trays upper flange appears to be in prelaunch condition but the paint dot on the clamp block located at the right end of the lower flange appears to be slightly discolored. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments

  15. LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D05

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D05 EL-1994-00038 LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D05 The flight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on the center clamp block of the experiment trays upper flange and on the tray clamp blocks at each end of the trays lower flange appear to be discolored by a brown stain. The experiment tray flanges also appear to be discolored by the stain. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical

  16. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D07

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D07 EL-1994-00207 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D07 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after removal of the experiment tray from the LDEF. The experiment tray flanges appear to be discolored by a light brown stain. An outline of experiment tray clamp block locations is clearly visible on the experiment trays upper flange and to a lesser extent on its lower flange. The holding fixture hardware covers the clamp block areas on the end flanges. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to

  17. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D01

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D01 EL-1994-00188 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D01 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC prior to removal of the experiment tray from the LDEF. The white paint dot on the experiment tray clamp block located at the center of the trays lower flange appears to be discolored by a brown stain. The experiment trays lower flange also appear to be coated but with a lighter colored stain. The white paint dots on clamp blocks at each end of the trays upper flange appear to be discolored very little. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is

  18. LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C11

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C11 EL-1994-00010 LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C11 The flight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on the center clamp block of the experiment trays left flange and on the clamp blocks located at the upper and lower ends of the experiment trays right flange appear to be in near prelaunch condition. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover

  19. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C08

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C08 EL-1994-00212 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C08 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after removal of the experiment tray from the LDEF. The experiment tray flanges appear discolored by a brown stain. Outlines of experiment tray clamp blocks are clearly visible on the upper and lower experiment tray flanges.The experiment tray holding fixture hardware covers the clamp block areas on the end flanges. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the

  20. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C11

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C11 EL-1994-00299 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C11 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after removal of the experiment tray from the LDEF. The experiment tray flanges appear discolored by a light brown stain. Outlines of experiment tray clamp blocks are faint but visible on the upper and lower experiment tray flanges.The experiment tray holding fixture hardware covers the clamp block areas on the end flanges. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground

  1. Ultra heavy nuclei in the cosmic radiation

    NASA Technical Reports Server (NTRS)

    Binns, W. Robert

    1988-01-01

    This paper describes the measurements of the ultraheavy cosmic ray abundances obtained by the Heavy Nuclei Experiment aboard the NASA High Energy Astronomy Observatory-3. It is found that the cosmic ray abundances are in broad agreement with solar system abundances with a step-FIP fractionation model applied although in detail there are some differences. In particular, Ge and Pb appear to be underabundant in the cosmic radiation. Although the platinum/lead ratio and the actinides are consistent with some r-process enhancement, the cosmic ray source is not dominated by the r-process up through the 50s as evidenced by the Sr/Rb ratio and by the abundance of Sn and Ba. The actinides are not greatly enhanced, ruling out freshly synthesized r-process production as the primary source of the heavy cosmic rays.

  2. Fusion probability in heavy nuclei

    NASA Astrophysics Data System (ADS)

    Banerjee, Tathagata; Nath, S.; Pal, Santanu

    2015-03-01

    Background: Fusion between two massive nuclei is a very complex process and is characterized by three stages: (a) capture inside the potential barrier, (b) formation of an equilibrated compound nucleus (CN), and (c) statistical decay of the CN leading to a cold evaporation residue (ER) or fission. The second stage is the least understood of the three and is the most crucial in predicting yield of superheavy elements (SHE) formed in complete fusion reactions. Purpose: A systematic study of average fusion probability, , is undertaken to obtain a better understanding of its dependence on various reaction parameters. The study may also help to clearly demarcate onset of non-CN fission (NCNF), which causes fusion probability, PCN, to deviate from unity. Method: ER excitation functions for 52 reactions leading to CN in the mass region 170-220, which are available in the literature, have been compared with statistical model (SM) calculations. Capture cross sections have been obtained from a coupled-channels code. In the SM, shell corrections in both the level density and the fission barrier have been included. for these reactions has been extracted by comparing experimental and theoretical ER excitation functions in the energy range ˜5 %-35% above the potential barrier, where known effects of nuclear structure are insignificant. Results: has been shown to vary with entrance channel mass asymmetry, η (or charge product, ZpZt ), as well as with fissility of the CN, χCN. No parameter has been found to be adequate as a single scaling variable to determine . Approximate boundaries have been obtained from where starts deviating from unity. Conclusions: This study quite clearly reveals the limits of applicability of the SM in interpreting experimental observables from fusion reactions involving two massive nuclei. Deviation of from unity marks the beginning of the domain of dynamical models of fusion. Availability of precise ER cross

  3. Clusterization and Deformation in Heavy Nuclei

    SciTech Connect

    Algora, A.; Cseh, J.; Darai, J.; Hess, P.O.; Antonenko, N.V.; Jolos, R.V.; Scheid, W.

    2005-11-21

    The deformation-dependence of clusterization in heavy nuclei is investigated. In particular, allowed and forbidden cluster-configurations are determined for the ground, superdeformed, and hyperdeformed states of some nuclei, based on a microscopic (effective SU(3)) selection rule. The stability of the different cluster configurations from the viewpoint of the binding energy and the dinuclear system model (DNS) is also investigated.

  4. Investigation of the relative abundance of heavy versus light nuclei in primary cosmic rays using underground muon bundles

    SciTech Connect

    Sundaralingam, N.

    1993-06-08

    We study multiple muon events (muon bundles) recorded underground at a depth of 2090 mwe. To penetrate to this depth, the muons must have energies above 0.8 TeV at the Earth`s surface; the primary cosmic ray nuclei which give rise to the observed muon bundles have energies at incidence upon the upper atmosphere of 10 to 10{sup 5}TeV. The events are detected using the Soudan 2 experiment`s fine grained tracking calorimeter which is surrounded by a 14 m {times}10 m {times} 31 m proportional tube array (the ``active shield``). Muon bundles which have at least one muon traversing the calorimeter, are reconstructed using tracks in the calorimeter together with hit patterns in the proportional tube shield. All ionization pulses are required to be coincident within 3 microseconds. A goal of this study is to investigate the relative nuclear abundances in the primary cosmic radiation around the ``knee`` region (10{sup 3} {minus} 10{sup 4} TeV) of the incident energy spectrum. Four models for the nuclear composition of cosmic rays are considered: The Linsley model, the Constant Mass Composition model (CMC), the Maryland model and the Proton-poor model. A Monte Carlo which incorporates one model at a time is used to simulate events which are then reconstructed using the same computer algorithms that are used for the data. Identical cuts and selections are applied to the data and to the simulated events.

  5. Review of metastable states in heavy nuclei.

    PubMed

    Dracoulis, G D; Walker, P M; Kondev, F G

    2016-07-01

    The structure of nuclear isomeric states is reviewed in the context of their role in contemporary nuclear physics research. Emphasis is given to high-spin isomers in heavy nuclei, with [Formula: see text]. The possibility to exploit isomers to study some of the most exotic nuclei is a recurring theme. In spherical nuclei, the role of octupole collectivity is discussed in detail, while in deformed nuclei the limitations of the K quantum number are addressed. Isomer targets and isomer beams are considered, along with applications related to energy storage, astrophysics, medicine, and experimental advances. PMID:27243336

  6. Review of metastable states in heavy nuclei

    NASA Astrophysics Data System (ADS)

    Dracoulis, G. D.; Walker, P. M.; Kondev, F. G.

    2016-07-01

    The structure of nuclear isomeric states is reviewed in the context of their role in contemporary nuclear physics research. Emphasis is given to high-spin isomers in heavy nuclei, with A≳ 150 . The possibility to exploit isomers to study some of the most exotic nuclei is a recurring theme. In spherical nuclei, the role of octupole collectivity is discussed in detail, while in deformed nuclei the limitations of the K quantum number are addressed. Isomer targets and isomer beams are considered, along with applications related to energy storage, astrophysics, medicine, and experimental advances.

  7. Octupole shapes in heavy nuclei

    SciTech Connect

    Ahmad, I.

    1994-08-01

    Theoretical calculations and measurements show the presence of strong octupole correlations in thecyround states and low-lying states of odd-mass and odd-odd nuclei in the RaPa region. Evidence for octupole correlations is provided by the observation of parity doublets and reductions in M1 matrix elements, decoupling parameters, and Coriolis matrix elements Involving high-j states. Enhancement of E1 transition rates has also been observed for some of the octupole deformed nuclei. The most convincing argument for octupole deformation is provided by the similarities of the reduced alpha decay rates to the two members of parity doublets.

  8. The Heavy Nuclei eXplorer (HNX) Small Explorer Mission

    NASA Astrophysics Data System (ADS)

    Mitchell, John; Binns, W. Robert; Hams, Thomas; Israel, Martin; Krizmanic, John; Link, Jason; Rauch, Brian; Sakai, Kenichi; Sasaki, Makoto; Westphal, Andrew; Wiedenbeck, Mark; Heavy Nuclei eXplorer Collaboration

    2015-04-01

    The Heavy Nuclei eXplorer (HNX) will investigate the nature of the reservoirs of nuclei at the cosmic-ray sources, the mechanisms by which nuclei are removed from the reservoirs and injected into the cosmic accelerators, and the acceleration mechanism. HNX will use two large high-precision instruments, the Extremely-heavy Cosmic-ray Composition Observer (ECCO) and the Cosmic-ray Trans-Iron Galactic Element Recorder (CosmicTIGER), flying in the SpaceX DragonLab, to measure, for the first time, the abundance of every individual element in the periodic table from carbon through the actinides, providing the first measurement of many of these elements. HNX will measure several thousand ultra-heavy galactic cosmic ray (UHGCR) nuclei Z >= 30, including about 50 actinides, and will: determine whether GCRs are accelerated from new or old material, and find their age; measure the mix of nucleosynthesis processes responsible for the UHGCRs; determine how UHGCR elements are selected for acceleration, and measure the mean integrated pathlength traversed by UHGCRs before observation. The scientific motivation and instrument complement of HNX will be discussed.

  9. The acceleration of heavy nuclei in solar flares

    NASA Technical Reports Server (NTRS)

    Sakurai, K.

    1974-01-01

    The overabundance of heavy nuclei in solar cosmic rays of energy approximately 5 Mev/nucleon is explained by taking into account the pre-flare ionization states of these nuclei in the region where they are accelerated. A model is proposed which considers two-step accelerations associated with the initial development of solar flares. The first step is closely related to the triggering process of flares, while the second one starts with the development of the explosive phase. Further ionization of medium and heavy nuclei occurs through their interaction with Kev electrons accelerated by the first-step acceleration. It is suggested that the role of these electrons is important in producing fully ionized atoms in the acceleration regions.

  10. The acceleration of heavy nuclei in solar flares

    NASA Technical Reports Server (NTRS)

    Sakurai, K.

    1975-01-01

    The overabundance of heavy nuclei in solar cosmic rays of energy below about 10 MeV/nucleon is explained by taking into account the pre-flare ionization states of these nuclei in the region where they are accelerated. A model is proposed which considers two-step accelerations associated with the initial development of solar flares. The first step is closely related to the triggering process of flares, while the second one starts with the development of the explosive phase. Further ionization of medium and heavy nuclei occurs through their interaction with keV electrons accelerated by the first-step acceleration. It is suggested that the role of these electrons is important in producing fully ionized atoms in the acceleration regions.

  11. Measurements of the fragmentation cross sections of relativistic heavy nuclei and their application to cosmic-ray propagation

    SciTech Connect

    Kertzman, M.P.

    1987-01-01

    The fragmentation cross sections of relativistic krypton, xenon, holmium and gold nuclei in targets of aluminium, carbon and polyethylene were measured. The beams were accelerated to maximum rigidity at the LBL Bevalac, corresponding to energies per nucleon of 1.5, 1.2, 1.1, and 1.0 Gev/amu for Kr, Xe, Ho, and Au respectively. The total and partial charge changing cross sections were determined for each beam and target combination, and cross sections in hydrogen were derived from the polyethylene (CH/sub 2/) and carbon data. The total cross sections were found to be 10% to 15% smaller than the predictions of a formula derived from measurements made with lower charge nuclei, and a new representation of the dependence of the total charge changing cross sections on beam and target charge was determined.

  12. Charge composition of high energy heavy primary cosmic ray nuclei. Ph.D. Thesis - Catholic Univ. of Am.

    NASA Technical Reports Server (NTRS)

    Price, R. D.

    1974-01-01

    A detailed study of the charge composition of primary cosmic radiation for about 5000 charged nuclei from neon to iron with energies greater than 1.16 GeV/nucleon is presented. Values are obtained after corrections were made for detector dependences, atmospheric attenuation, and solar modulation. New values of 38.5, 32.4, 23.7, and 16.8 g/sq cm for the attenuation mean free paths in air for the same charge groups are presented.

  13. The intergalactic propagation of ultrahigh energy cosmic ray nuclei

    SciTech Connect

    Hooper, Dan; Sarkar, Subir; Taylor, Andrew M.; /Oxford U.

    2006-08-01

    We investigate the propagation of ultra-high energy cosmic ray nuclei (A = 1-56) from cosmologically distant sources through the cosmic radiation backgrounds. Various models for the injected composition and spectrum and of the cosmic infrared background are studied using updated photodisintegration cross-sections. The observational data on the spectrum and the composition of ultra-high energy cosmic rays are jointly consistent with a model where all of the injected primary cosmic rays are iron nuclei (or a mixture of heavy and light nuclei).

  14. Exotic nuclei with open heavy flavor mesons

    SciTech Connect

    Yasui, Shigehiro; Sudoh, Kazutaka

    2009-08-01

    We propose stable exotic nuclei bound with D and B mesons with respect to heavy quark symmetry. We indicate that an approximate degeneracy of D(B) and D*(B*) mesons plays an important role, and discuss the stability of DN and BN bound states. We find the binding energies 1.4 MeV and 9.4 MeV for each state in the J{sup P}=1/2{sup -} with the I=0 channel. We discuss also possible existence of exotic nuclei DNN and BNN.

  15. The Heavy Nuclei eXplorer (HNX) Mission

    NASA Astrophysics Data System (ADS)

    Krizmanic, John; Mitchell, John; Binns, W. Robert; Hams, Thomas; Israel, Martin; Link, Jason; Rauch, Brian; Sakai, Kenichi; Sasaki, Makoto; Westphal, Andrew; Wiedenbeck, Mark; Heavy Nuclei eXplorer Collaboration

    2016-03-01

    The Heavy Nuclei eXplorer (HNX) will use two large high-precision instruments, the Extremely-heavy Cosmic-ray Composition Observer (ECCO) and the Cosmic-ray Trans-Iron Galactic Element Recorder (CosmicTIGER), designed to fly in a SpaceX DragonLab Capsule, to measure the cosmic-ray abundance of every individual element in the periodic table from carbon through curium, providing the first measurement of many of these elements. These measurements provide an investigation on the nature of the source material of cosmic rays, the processes that inject them into cosmic accelerators, and the acceleration mechanisms. HNX will measure several thousand ultra-heavy galactic cosmic ray (UHGCR) nuclei with Z >= 30 , including about 50 actinides (Z >= 79). These data allow for a measurement of the mix of new and old material that is accelerated to GCRs, determine their age, measure the mix of nucleosynthesis processes responsible for the UHGCRs, determine how UHGCR elements are selected for acceleration, and measure the mean integrated pathlength traversed by UHGCRs before observation. The scientific motivation and instrumentation of HNX will be discussed as well as recent beam test results.

  16. Comparison of Muon Capture in Light and in Heavy Nuclei

    SciTech Connect

    Measday, David F.; Stocki, Trevor J.

    2007-10-26

    We have recently completed an experimental study at TRIUMF of muon capture in the following elements, N, Al, Si, Ca, Fe, Ni, I, Au, and Bi. We detected the nuclear gamma rays emitted by the product nuclei after muon capture. The energy of the gamma ray identifies the source nuclide, and thus the reaction which has occurred. Our data are of better quality, and more comprehensive than any other data set in the literature. The ({mu}{sup -},{nu}n) reaction is always dominant. In light nuclei, reactions such as ({mu}{sup -},{nu}p) and ({mu}{sup -},{nu}pn) can occur, but not for heavy nuclei. However the reverse is true for reactions such as ({mu}{sup -},{nu}3n) and ({mu}{sup -},{nu}4n), which are very rare in light nuclei, but easily detected in heavy elements. We shall discuss how such information can be useful in calculations of neutrino-nucleus interactions, and of electron-capture in supernovae.

  17. Formation of Slow Heavy Mesons in Nuclei

    NASA Astrophysics Data System (ADS)

    Hirenzaki, Satoru

    2009-10-01

    Meson - nucleus systems such as mesic atoms and mesic nuclei have been studied systematically for a long time. The binding energies and widths of these bound states provide us unique and valuable information on the meson-nucleus interactions. In addition, the measurements of light vector meson spectra in nucleus as the invariant mass of lepton pairs have also provided interesting information. So far, the properties of relatively light mesons have been studied well both theoretically and experimentally. In this contribution, to extend our studies to a domain of heavier mesons, we would like to report recent research activities on the formation of heavy mesons in nuclei with small momenta. We think it is very interesting to consider the in-medium properties of heavier mesons including heavy quark contents. As a first step to heavier mesons, we will report our studies on formation of slow phi meson in nuclei. In-medium properties of phi meson have been studied theoretically, which have close relation to K and K-bar meson properties in medium because of the strong coupling of phi to K and K-bar. The study of QCD sum rule and the data taken at KEK suggested 3 percent mass reduction of phi at the normal nuclear density, while the phi meson selfenergy calculated in some effective models indicated a significantly smaller attractive potential for phi. We will show the calculated spectra for some reactions.

  18. Relativistic heavy cosmic rays

    NASA Technical Reports Server (NTRS)

    Mewaldt, R. A.; Fernandez, J. I.; Israel, M. H.; Klarmann, J.; Binns, W. R.

    1972-01-01

    During three balloon flights of a 1 sq m sr ionization chamber/Cerenkov counter detector system, measurements were made of the atmospheric attenuation, flux, and charge composition of cosmic ray nuclei with 16 is less than or = Z is less than or = 30 and rigidity greater than 4.5 GV. The attenuation mean free path in air of VH (20 less than or = Z less than or = 30) nuclei is found to be 19.7 + or - 1.6 g/sq cm, a value somewhat greater than the best previous measurement. The attenuation mean free path of iron is found to be 15.6 + or - 2.2 g/sq cm, consistent with predictions of geometric cross-section formulae. An absolute flux of VH nuclei 10 to 20% higher than earlier experiments at similar geomagnetic cutoff and level of solar activity was measured. The relative abundances of even-charged nuclei are found to be in good agreement with results of other recent high resolution counter experiments. The observed cosmic ray chemical composition implies relative abundances at the cosmic ray source of Ca/Fe = 0.12 + or - 0.04 and S/Fe = 0.14 + or - 0.05.

  19. Nuclei at HERA and heavy ion physics

    SciTech Connect

    Gavin, S.; Strikman, M.

    1995-12-31

    Copies of 16 viewgraph sets from a workshop held at Brookhaven National Laboratory, 17-18 November, 1995. Titles of talks: HERA: The Present; HERA: Potential with Nuclei; Review of Hadron-Lepton Nucleus Data; Fermilab E665: results in muon scattering; Interactions of Quarks and Gluons with Nuclear Matter; Rescattering in Nuclear Targets for Photoproduction and DIS; Structure Functions and Nuclear Effect at PHENIX; Probing Spin-Averaged and Spin-Dependent Parton Distributions Using the Solenoidal Tracker at RHIC (STAR); Jet Quenching in eA, pA, AA; Nuclear Gluon Shadowing via Continuum Lepton Pairs; What can we learn from HERA with a colliding heavy ion beam? The limiting curve of leading particles at infinite A; Coherent Production of Vector Mesons off Light Nuclei in DIS; A Model of High Parton Densities in PQCD; Gluon Production for Weizaecker-Williams Field in Nucleus-Nucleus Collisions; Summary Talk.

  20. Heavy-particle radioactivity of superheavy nuclei.

    PubMed

    Poenaru, D N; Gherghescu, R A; Greiner, W

    2011-08-01

    The concept of heavy-particle radioactivity (HPR) is changed to allow emitted particles with Z(e) > 28 from parents with Z > 110 and daughter around (208)Pb. Calculations for superheavy (SH) nuclei with Z = 104-124 are showing a trend toward shorter half-lives and larger branching ratio relative to α decay for heavier SHs. It is possible to find regions in which HPR is stronger than alpha decay. The new mass table AME11 and the theoretical KTUY05 and FRDM95 masses are used to determine the released energy. For 124 we found isotopes with half-lives in the range of ns to ps. PMID:21902317

  1. Abundances of cosmic ray nuclei heavier than 50 Sn

    NASA Technical Reports Server (NTRS)

    Waddington, C. J.; Fickle, R. K.; Garrard, T. L.; Stone, E. C.; Binns, W. R.; Israel, M. H.; Klarmann, J.

    1982-01-01

    Preliminary results are reported from 430 days of exposure of the heavy nuclei experiment on the HEAO-3 spacecraft. These results are confined to the heavy nuclei with Z equal to or greater than 50 and emphasize the conclusions obtained on the relative numbers of actinides and heavy stable elements in the lead-platinum region. The extreme paucity of actinides found is inconsistent with the predictions of a cosmic ray source that is highly enriched in r-process material, but quite consistent with a source whose composition is similar to that of normal solar system material. An upper limit, at the 95 percent confidence level, is placed in the ratio of nuclei with Z equal to or greater than 88/(Z in the range from 74 to 87) of 0.03.

  2. Active Galactic Nuclei:. Sources for Ultra High Energy Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Biermann, P. L.; Becker, J. K.; Caramete, L.; Gergely, L.; Mariş, I. C.; Meli, A.; de Souza, V.; Stanev, T.

    Ultra high energy cosmic ray events presently show a spectrum, which we interpret here as galactic cosmic rays due to a starburst, in the radio galaxy Cen A which is pushed up in energy by the shock of a relativistic jet. The knee feature and the particles with energy immediately higher in galactic cosmic rays then turn into the bulk of ultra high energy cosmic rays. This entails that all ultra high energy cosmic rays are heavy nuclei. This picture is viable if the majority of the observed ultra high energy events come from the radio galaxy Cen A, and are scattered by intergalactic magnetic fields across much of the sky.

  3. Interactions of heavy nuclei, Kr, Xe and Ho, in light targets

    NASA Technical Reports Server (NTRS)

    Kertzman, M. P.; Klarmann, J.; Newport, B. J.; Stone, E. C.; Waddington, C. J.; Binns, W. R.; Garrard, T. L.; Israel, M. H.

    1985-01-01

    Over the past few years, the HEAO-3 measurements of the abundance of ultra-heavy cosmic ray nuclei (Z 26) at Earth were analyzed. In order to interpret these abundances in terms of a source composition, allowances must be made for the propagation of the nuclei in the interstellar medium. Vital to any calculation of the propagation is a knowlege of the total and partial interaction cross sections for these heavy nuclei on hydrogen. Until recently, data on such reactions have been scarce. The semi-empirical formalism of Silberberg and Tsao were relied upon to predict the partial cross sections. However, now that relativistic heavy ion beams are available at the LBL Bevalac, some of the cross sections of interest can be measured at energies close to those of the cosmic ray nuclei being observed.

  4. X-ray decay lines from heavy nuclei in supernova remnants as a probe of the r-process origin and the birth periods of magnetars

    NASA Astrophysics Data System (ADS)

    Ripley, Justin L.; Metzger, Brian D.; Arcones, Almudena; Martínez-Pinedo, Gabriel

    2014-03-01

    The origin of rapid neutron capture (r-process) nuclei remains one of the longest standing mysteries in nuclear astrophysics. Core collapse supernovae (SNe) and neutron star binary mergers are likely r-process sites, but little evidence yet exists for their in situ formation in such environments. Motivated by the advent of sensitive new or planned X-ray telescopes such as the Nuclear Spectroscopic Telescope Array (NuSTAR) and the Large Observatory for X-ray Timing (LOFT), we revisit the prospects for the detection of X-ray decay lines from r-process nuclei in young or nearby supernova remnants. For all remnants planned to be observed by NuSTAR (and several others), we conclude that r-process nuclei are detectable only if the remnant possesses a large overabundance O ≳ 10^3 relative to the average yield per SN. Prospects are better for the next Galactic SN (assumed age of 3 yr and distance of 10 kpc), for which an average r-process yield is detectable via the 10.7 (9.2) keV line complexes of 194Os by LOFT at 6σ (5σ) confidence; the 27.3 keV line complex of 125Sb is detectable by NuSTAR at 2σ for O ≳ 2. We also consider X-rays lines from the remnants of Galactic magnetars, motivated by the much higher r-process yields of the magnetorotationally driven SNe predicted to birth magnetars. The ˜3.6-3.9 keV lines of 126Sn are potentially detectable in the remnants of the magnetars 1E1547.0-5408 and 1E2259+586 by LOFT for an assumed r-process yield predicted by recent simulations. The (non-)detection of these lines can thus probe whether magnetars are indeed born with millisecond periods. Finally, we consider a blind survey of the Galactic plane with LOFT for r-process lines from the most recent binary neutron star merger remnant, concluding that a detection is unlikely without additional information on the merger location.

  5. Mechanism of heavy ion fusion to superheavy nuclei

    NASA Astrophysics Data System (ADS)

    Adamian, Gurgen G.; Antonenko, Nikolai V.; Scheid, Werner

    2011-10-01

    This article reviews different models for the description of fusion of heavy ions to superheavy nuclei by using adiabatic and diabatic potentials. The dynamics of fusion is basically different in the two types of models for fusion: In the adiabatic models the nuclei melt together, whereas in the diabatic models the nuclei transfer nucleons between each other up to the instant when the compound nucleus is formed. As final result we state that diabatic potentials seem more appropriate for the description of fusion of heavy nuclei than adiabatic potentials.

  6. Interactions of heavy nuclei, Kr, Xe and Ho, in light targets

    NASA Technical Reports Server (NTRS)

    Kertzman, M. P.; Klarmann, J.; Newport, B. J.; Stone, E. C.; Waddington, C. J.; Binns, W. R.; Garrard, T. L.; Israel, M. H.

    1985-01-01

    Over the past few years, the HEAO-3 measurements of the abundances of ultra-heavy cosmic ray nuclei (Z 26) at earth have been analyzed. In order to interpret these abundances in terms of a source composition, allowance must be made for the propagation of the nuclei in the interstellar medium. Vital to any calculation of the propagation is a knowlege of the total and partial interaction cross sections for these heavy nuclei on hydrogen. Until recently, data on such reactions have been scarce. However, now that relativistic heavy ion beams are available at the LBL Bevalac, some of the cross sections of interest can be measured at energies close to those of the cosmic ray nuclei being observed. During a recent calibration at the Bevalac of an array similar to the HEAO-C3 UH-nuclei detector, targets of raphite (C), polyethylene (CH2), and aluminum were exposed to five heavy ion beams ranging in charge (Z) from 36 to 92. Total and partial charge changing cross sections for the various beam nuclei on hydrogen can be determined from the measured cross sections on C and CH2, and will be applied to the propagation problem. The cross sections on Al can be used to correct the abundances of UH cosmic rays observed in the HEAO C-3 detector for interactions in the detector itself.

  7. Ultra heavy cosmic ray experiment (A0178)

    NASA Technical Reports Server (NTRS)

    Thompson, A.; Osullivan, D.; Bosch, J.; Keegan, R.; Wenzel, K. P.; Jansen, F.; Domingo, C.

    1992-01-01

    The Ultra Heavy Cosmic Ray Experiment (UHCRE) is based on a modular array of 192 side viewing solid state nuclear track detector stacks. These stacks were mounted in sets of four in 48 pressure vessels using 16 peripheral LDEF trays. The geometry factor for high energy cosmic ray nuclei, allowing for Earth shadowing, was 30 sq m sr, giving a total exposure factor of 170 sq m sr y at an orbital inclination of 28.4 degs. Scanning results indicate that about 3000 cosmic ray nuclei in the charge region with Z greater than 65 were collected. This sample is more than ten times the current world data in the field (taken to be the data set from the HEAO-3 mission plus that from the Ariel-6 mission) and is sufficient to provide the world's first statistically significant sample of actinide cosmic rays. Results are presented including a sample of ultra heavy cosmic ray nuclei, analysis of pre-flight and post-flight calibration events and details of track response in the context of detector temperature history. The integrated effect of all temperature and age related latent track variations cause a maximum charge shift of + or - 0.8e for uranium and + or - 0.6e for the platinum-lead group. Astrophysical implications of the UHCRE charge spectrum are discussed.

  8. Reactions of synthesis of heavy nuclei: Brief summary and outlook

    SciTech Connect

    Oganessian, Yu. Ts.

    2006-06-15

    The possible reactions of synthesis of extremely heavy nuclei with almost closed proton and neutron shells are analyzed on the basis of current experimental and theoretical data on the properties of the isotopes of superheavy elements. It has been shown that advances in obtaining extremely heavy nuclei for which microscopic models predict an increase in stability require further investigations of the mechanism of synthesis reactions. Direct and model experiments aimed at solving this problem are discussed.

  9. Analytic expressions for {alpha} particle preformation in heavy nuclei

    SciTech Connect

    Zhang, H. F.; Wang, Y. J.; Dong, J. M.; Royer, G.

    2009-11-15

    Experimental {alpha} decay energies and half-lives are investigated systematically to extract {alpha} particle preformation in heavy nuclei. Formulas for the preformation factors are proposed that can be used to guide microscopic studies on preformation factors and perform accurate calculations of the {alpha} decay half-lives. There is little evidence for the existence of an island of long stability of superheavy nuclei.

  10. Cosmic Ray Nuclei (CRN) detector investigation

    NASA Technical Reports Server (NTRS)

    Meyer, Peter; Muller, Dietrich; Lheureux, Jacques; Swordy, Simon

    1991-01-01

    The Cosmic Ray Nuclei (CRN) detector was designed to measure elemental composition and energy spectra of cosmic radiation nuclei ranging from lithium to iron. CRN was flown as part of Spacelab 2 in 1985, and consisted of three basic components: a gas Cerenkov counter, a transition radiation detector, and plastic scintillators. The results of the experiment indicate that the relative abundance of elements in this range, traveling at near relativistic velocities, is similar to those reported at lower energy.

  11. Bose condensation of nuclei in heavy ion collisions

    NASA Technical Reports Server (NTRS)

    Tripathi, Ram K.; Townsend, Lawrence W.

    1994-01-01

    Using a fully self-consistent quantum statistical model, we demonstrate the possibility of Bose condensation of nuclei in heavy ion collisions. The most favorable conditions of high densities and low temperatures are usually associated with astrophysical processes and may be difficult to achieve in heavy ion collisions. Nonetheless, some suggestions for the possible experimental verification of the existence of this phenomenon are made.

  12. Studies of heavy-ion reactions and transuranic nuclei

    NASA Astrophysics Data System (ADS)

    Schroeder, W. U.

    1993-08-01

    Papers on the following topics are included: The Cold-Fusion Saga; Decay Patterns of Dysprosium Nuclei Produced in S-32 + Sn-118,124 Fusion Reactions; Unexpected Features of Reactions Between Very Heavy Ions at Intermediate Bombarding Energies; Correlations Between Neutrons and Charged Products from the Dissipative Reaction Au-197 + Pb-208 at E/A = 29 MeV; Dissipative Dynamics of Projectile-Like Fragment Production in the Reaction Bi-209 + Xe-136 at E/A = 28.2 MeV; Dynamical Production of Intermediate-Mass Fragments in Peripheral Bi-209 + Xe-136 Collisions at E(sub lab)/A = 28.2 MeV; The Rochester 960-Liter Neutron Multiplicity Meter; A Simple Pulse Processing Concept for a Low-Cost Pulse-Shape-Based Particle Identification; A One-Transistor Preamplifier for PMT Anode Signals; A Five-Channel Multistop TDC/Event Handler for the SuperBall Neutron Multiplicity Meter; Construction of the SuperBall - a 16,000-Liter Neutron Detector for Calorimetric Studies of Intermediate-Energy Heavy-Ion Reactions; A Computer Code for Light Detection Efficiency Calculations for Photo-multipliers of a Neutron Detector; Evaluation of Gd-Loaded Liquid Scintillators for the SuperBall Neutron Calorimeter; and Measurement of the Interaction of Cosmic-Ray mu(-) with a Muon Telescope.

  13. The response of ionization chambers to relativistic heavy nuclei

    NASA Technical Reports Server (NTRS)

    Newport, B. J.; Stone, E. C.; Waddington, C. J.; Binns, W. R.; Fixsen, D. J.; Garrard, T. L.; Grimm, G.; Israel, M. H.; Klarmann, J.

    1985-01-01

    The LBL Bevalac for the Heavy Nuclei Experiment on HEAO-3, compared the response of a set of laboratory ionization chambers to beams of 26Fe, 36Kr, 54Xe, 67 Ho, and 79Au nuclei at maximum energies ranging from 1666 MeV/amu for Fe to 1049 MeV/amu for Au. The response of these chambers shows a significant deviation from the expected energy dependence, but only a slight deviation from Z sq scaling.

  14. Transport of cosmic ray nuclei in various materials

    NASA Technical Reports Server (NTRS)

    Silberberg, R.; Tsao, C. H.; Letaw, J. R.

    1988-01-01

    Cosmic-ray heavy ions have become a concern in space radiation effects analyses. Heavy ions rapidly deposit energy and create dense ionization trails as they traverse materials. Collection of the free charge disrupts the operation of microelectronic circuits. This effect, called the single-event upset, can cause a loss of digital data. Passage of high linear energy transfer particles through the eyes has been observed by Apollo astronauts. These heavy ions have great radiobiological effectiveness and are the primary risk factor for leukemia induction on a manned Mars mission. Models of the transport of heavy cosmic-ray nuclei through materials depend heavily on our understanding of the cosmic-ray environment, nuclear spallation cross sections, and computer transport codes. Our group has initiated and pursued the development of a full capability for modeling these transport processes. A recent review of this ongoing effort is presented in Ref. 5. In this paper, we discuss transport methods and present new results comparing the attenuation of cosmic rays in various materials.

  15. Transport of cosmic ray nuclei in various materials.

    PubMed

    Silberberg, R; Tsao, C H; Letaw, J R

    1988-01-01

    Cosmic-ray heavy ions have become a concern in space radiation effects analyses. Heavy ions rapidly deposit energy and create dense ionization trails as they traverse materials. Collection of the free charge disrupts the operation of microelectronic circuits. This effect, called the single-event upset, can cause a loss of digital data. Passage of high linear energy transfer particles through the eyes has been observed by Apollo astronauts. These heavy ions have great radiobiological effectiveness and are the primary risk factor for leukemia induction on a manned Mars mission. Models of the transport of heavy cosmic-ray nuclei through materials depend heavily on our understanding of the cosmic-ray environment, nuclear spallation cross sections, and computer transport codes. Our group has initiated and pursued the development of a full capability for modeling these transport processes. A recent review of this ongoing effort is presented in Ref. 5. In this paper, we discuss transport methods and present new results comparing the attenuation of cosmic rays in various materials. PMID:11538213

  16. Formation of Heavy and Superheavy Neutron Rich Nuclei

    SciTech Connect

    Zagrebaev, Valery; Greiner, Walter

    2010-04-30

    A new way is proposed to discover and examine unknown neutron-rich heavy and superheavy nuclei at the 'north-east' part of the nuclear map. The present limits of the upper part of the nuclear map is very close to stability while the unexplored area of heavy neutron-rich nuclides to the east of the stability line (also those located along the neutron closed shell N = 126) is extremely important for nuclear astrophysics investigations and for the understanding of the r-process of astrophysical nucleo-genesis. A novel idea is proposed for the production of these nuclei via low-energy multi-nucleon transfer reactions using a gain given by the shell effects. This finding may spur new studies at heavy ion facilities and should have significant impact for future experiments. The use of the multi-nucleon transfer reactions in low-energy collisions of heavy actinide nuclei gives us also the only chance to approach the 'island of stability' of superheavy elements. A possibility for a three-body decay (heavy ternary fission) is predicted for superheavy nuclei.

  17. Bose condensation of nuclei in heavy ion collisions.

    PubMed

    Tripathi, R K; Townsend, L W

    1994-07-01

    Using a fully self-consistent quantum statistical model, we demonstrate the possibility of Bose condensation of nuclei in heavy ion collisions. The most favorable conditions of high densities and low temperatures are usually associated with astrophysical processes and may be difficult to achieve in heavy ion collisions. Nonetheless, some suggestions for the possible experimental verification of the existence of this phenomenon are made. PMID:9969695

  18. Photo-disintegration of heavy nuclei at the core of Cen A

    SciTech Connect

    Kundu, Esha; Gupta, Nayantara E-mail: nayan@rri.res.in

    2014-04-01

    Fermi LAT has detected gamma ray emissions from the core of Cen A. More recently, a new component in the gamma ray spectrum from the core has been reported in the energy range of 4 GeV to tens of GeV. We show that the new component and the HESS detected spectrum of gamma rays from the core at higher energy have possibly a common origin in photo-disintegration of heavy nuclei. Assuming the cosmic rays are mostly Fe nuclei inside the core and their spectrum has a low energy cut-off at 52 TeV in the wind frame moving with a Doppler factor 0.25 with respect to the observer on earth, the cosmic ray luminosity required to explain the observed gamma ray flux above 1 GeV is found to be 1.5 × 10{sup 43} erg/sec.

  19. Gamma rays from active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Kazanas, Demosthenes

    1990-01-01

    The general properties of Active Galactic Nuclei (AGN) and quasars are reviewed with emphasis on their continuum spectral emission. Two general classes of models for the continuum are outlined and critically reviewed in view of the impending GRO (Gamma Ray Observatory) launch and observations. The importance of GRO in distinguishing between these models and in general in furthering the understanding of AGN is discussed. The very broad terms the status of the current understanding of AGN are discussed.

  20. Recent studies of heavy nuclei far from stability at JYFL

    SciTech Connect

    Julin, R.; Enqvist, T.; Helariutta, K.

    1996-12-31

    The new K=130 Cyclotron + ECR facility of the Physics Department of the University of Jyvaskyla (JYFL) provides stable beams from protons up to krypton ions for nuclear structure studies. Two instruments designed especially for in-beam spectroscopic studies of heavy nuclei at JYFL are introduced in this contribution. Some results from recent measurements with them are reported.

  1. A Semi-microscopic Approach to Clusterization in Heavy Nuclei

    SciTech Connect

    Darai, J.; Cseh, J.; Antonenko, N. V.; Jolos, R. V.; Algora, A.; Hess, P. O.; Scheid, W.

    2009-08-26

    We present a semimicroscopic approach to clusterization in heavy nuclei. The method is largely based on symmetry-considerations. As an example we determine the possible binary clusterizations of the shape isomers of the {sup 56}Ni nucleus. We combine our structure-considerations with energy-calculations.

  2. Radiative corrections to high energy lepton bremsstrahlung on heavy nuclei

    NASA Astrophysics Data System (ADS)

    Arbuzov, Andrej B.

    2008-01-01

    One-loop radiative corrections to the leptonic tensor in high energy bremsstrahlung on heavy nuclei are calculated. Virtual and real photon radiation is taken into account. Double bremsstrahlung is simulated by means of Monte Carlo. Numerical results are presented for the case of muon bremsstrahlung in conditions of the COMPASS experiment at CERN.

  3. The LDEF ultra heavy cosmic ray experiment

    NASA Technical Reports Server (NTRS)

    Osullivan, D.; Thompson, A.; Bosch, J.; Keegan, R.; Wenzel, K.-P.; Smit, A.; Domingo, C.

    1992-01-01

    The LDEF Ultra Heavy Cosmic Ray Experiment (UHCRE) used 16 side viewing LDEF trays giving a total geometry factor for high energy cosmic rays of 30 sq m sr. The total exposure factor was 170 sq m sr y. The experiment is based on a modular array of 192 solid state nuclear track detector stacks, mounted in sets of four in 48 pressure vessels. The extended duration of the LDEF mission has resulted in a greatly enhanced potential scientific yield from the UHCRE. Initial scanning results indicate that at least 1800 cosmic ray nuclei with Z greater than 65 were collected, including the world's first statistically significant sample of actinides. Post flight work to date and the current status of the experiment are reviewed.

  4. The LDEF ultra heavy cosmic ray experiment

    NASA Technical Reports Server (NTRS)

    Osullivan, D.; Thompson, A.; Bosch, J.; Keegan, R.; Wenzel, K.-P.; Smit, A.; Domingo, C.

    1991-01-01

    The Long Duration Exposure Facility (LDEF) Ultra Heavy Cosmic Ray Experiment (UHCRE) used 16 side viewing LDEF trays giving a total geometry factor for high energy cosmic rays of 30 sq m sr. The total exposure factor was 170 sq m sr y. The experiment is based on a modular array of 192 solid state nuclear track detector stacks, mounted in sets of 4 pressure vessels (3 experiment tray). The extended duration of the LDEF mission has resulted in a greatly enhanced potential scientific yield from the UHCRE. Initial scanning results indicate that at least 2000 cosmic ray nuclei with Z greater than 65 were collected, including the world's first statistically significant sample of actinides. Postflight work to date and the current status of the experiment are reviewed. Provisional results from analysis of preflight and postflight calibrations are presented.

  5. Properties of heavy and superheavy nuclei in supernova environments

    SciTech Connect

    Buervenich, T. J.; Mishustin, I. N.; Greiner, W.

    2008-05-12

    The properties of nuclei embedded in an electron gas are studied within the relativistic mean-field approach. These studies are relevant for nuclear properties in astrophysical environments such as neutron-star crusts and supernova explosions. The electron gas is treated as a constant background in the Wigner-Seitz cell approximation. We investigate the stability of nuclei with respect to {alpha} and {beta} decay. We find that the presence of the electrons leads to stabilizing effects for {alpha} decay at high electron densities. Furthermore, the screening effect shifts the proton dripline to more proton-rich nuclei, and the stability line with respect to {beta}-decay is shifted to more neutron-rich nuclei. Implications for the creation and survival of very heavy nuclear systems are discussed.

  6. The response of ionization chambers to relativistic heavy nuclei

    NASA Technical Reports Server (NTRS)

    Newport, B. J.; Stone, E. C.; Waddington, C. J.; Binns, W. R.; Fixsen, D. J.; Garrard, T. L.; Grimm, G.; Israel, M. H.; Klarmann, J.

    1985-01-01

    As part of a recent calibration at the LBL Bevalac for the Heavy Nuclei Experiment on HEAO-3, the response of a set of laboratory ionization chambers were compared to beams of 26Fe, 36 Kr, 54Xe, 67 Ho, and 79 Au nuclei at maximum energies ranging from 1666 MeV/amu for Fe to 1049 MeV/amu for Au. The response of these chambers shows a significant deviation from the expected energy dependence, but only a slight deviation from Z squared scaling.

  7. Quantum effects in low-energy photofission of heavy nuclei

    SciTech Connect

    Tsipenyuk, Y.M.; Ostapenko, Y.B.; Smirenkin, G.N.; Soldatov, A.S.

    1984-09-01

    The article is devoted to quantum effects in highly deformed nuclei and the related features of the fission mechanism in the low-energy photofission of heavy nuclei. The following questions are considered: the spectrum of transition states (fission channels), the symmetry of the nuclear configuration in the deformation process, the features of the passage through the barrier due to the existence in the second well of quasistationary states of fissile and nonfissile modes, the isomeric-shelf phenomenon in deep sub-barrier fission, and the relation between the fragment mass distribution and the structure of the fission barrier.

  8. Determination of the charge of relativistic heavy nuclei from emulsion tracks

    NASA Technical Reports Server (NTRS)

    Morgan, S. H., Jr.; Eby, P. B.

    1971-01-01

    The number of delta rays with energies between 50 and 150 keV that are produced by heavy nuclei in emulsions is calculated. The Z(2) dependence predicted by the first Born approximation is corrected by a direct calculation of the Mott exact phase-shift scattering cross section. Comparisons are made with corrections predicted by the second Born approximation. When the phase-shift results are applied to the problem of charge identification, corrections of up to 4 units of charge for 1.457-GeV/nucleon nuclei with charge Z = 75 are found.

  9. Capabilities of the LDEF-2 heavy nuclei collection

    NASA Technical Reports Server (NTRS)

    Drach, J.; Price, P. B.; Salamon, M. H.; Tarle, G.; Ahlen, S. P.

    1985-01-01

    To take the next big step beyond High Energy Astronomy Observatory (HEAO-3) the Heavy Nuclei Collector (HNC), to be carried on an LDEF reflight, has the goals of greatly increased collecting power ( 30 actinides) and charge resolution sigma sub Z or = 0.25 E for Z up to approximately 100, which will provide abundances of all the charges 40 or Z or = 96 and permit sensitive searches for hypothetical particles such as monopoles, superheavy elements, and quark nuggets.

  10. Post-launch analysis of data from the High Energy Astrophysical Observatory Heavy Nuclei Experiment (HEAO-C3)

    NASA Technical Reports Server (NTRS)

    Stone, E. C.

    1992-01-01

    The Final Report on the continuing analysis of data from the Heavy Nuclei Experiment (HNE), flown on the HEAO-3 mission, is presented. The HNE was designed to measure the elemental abundances of relativistic cosmic ray nuclei covering the charge range 17 is less than or equal to Z is less than or equal to 130. The result of these measurements is significant to the study of nucleosynthesis, the origin, acceleration, and propagation of cosmic ray nuclei, and the properties of the interstellar medium.

  11. The Heavy Nuclei eXplorer (HNX) Mission

    NASA Technical Reports Server (NTRS)

    Binns, W. R.; Adams, J. H.; Barbier, L. M.; Craig, N.; Cummings, A. C.; Cummings, J. R.; Doke, T.; Hasebe, N.; Hayashi, T.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    The primary scientific objectives of HNX, which was recently selected by NASA for a Small Explorer (SMEX) Mission Concept Study, are to measure the age of the galactic cosmic rays (GCR) since nucleosynthesis, determine the injection mechanism for the GCR accelerator (Volatility or FIP), and study the mix of nucleosynthetic processes that contribute to the source of GCRs. The experimental goal of HNX is to measure the elemental abundances of all individual stable nuclei from neon through the actinides and possibly beyond. HNX is composed of two instruments: ECCO, which measures elemental abundances of nuclei with Z greater than or equal to 72, and ENTICE. which measures elemental abundances of nuclei with Z between 10 and 82. We describe the mission and the science that can be addressed by HNX.

  12. The Energetic Trans-Iron Composition Experiment (ENTICE) on the Heavy Nuclei Explorer (HNX) Mission

    NASA Technical Reports Server (NTRS)

    Hink, P. L.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    The Energetic Trans-Iron Composition Experiment (ENTICE) experiment is one of two experiments which comprise the Heavy Nuclei Explorer (HNX) mission. The experimental goal of ENTICE is to measure with high precision the elemental abundances of all nuclei with 10LZL82. This will enable us to determine if the injection mechanism for the cosmic ray accelerator is controlled by FIP or Volatility and to study the mix of nucleosynthetic processes that contribute to the galactic cosmic ray source. The ENTICE experiment utilizes the dE/dx-C method of charge determination and consists of silicon dE/dx detectors, Cherenkov detectors with two different refractive indices, and a scintillating fiber hodoscope. The geometrical factor of the instrument is approximately 8m2sr. We will present a description of the instrument and its expected performance based on beam tests and a balloon flight of a prototype instrument.

  13. Fusion and fission of heavy and superheavy nuclei (experiment)

    NASA Astrophysics Data System (ADS)

    Itkis, M. G.; Vardaci, E.; Itkis, I. M.; Knyazheva, G. N.; Kozulin, E. M.

    2015-12-01

    The scope of this review is to summarize the main advancements in the search of signatures of the compound nucleus fission and quasifission processes in heavy and superheavy systems. The understanding of fusion and fission in heavy and superheavy elements is needed for tracing paths aimed at reaching the island of stability situated near Z = 114- 122 and N = 184. With increasing charge of the interacting nuclei other processes, like quasifission, emerge and compete against fusion. Hence also their study must be pursued. After a brief look at the experimental techniques, the behavior of several observables is extracted from the most recent data to aid in the disentanglement of the various competing processes which hinder the production of superheavy elements.

  14. Gamma ray astronomy and the origin of the light nuclei. [cosmic ray and interstellar gas reactions

    NASA Technical Reports Server (NTRS)

    Reeves, H.

    1978-01-01

    Nuclear reactions induced by the collisions of the protons and alphas of the galactic cosmic ray with heavy nuclei of the interstellar gas are responsible for the continuous production of the light elements lithium, beryllium, and boron in the galaxy. To better than one order of magnitude, the observed ratios of these abundances to hydrogen abundance and the nuclidic abundance ratios between themselves are accounted for by simply considering the effect of fast protons and alphas with a flux and an energy spectrum as observed in galactic cosmic rays, for a period comparable with the life of our galaxy. The role of gamma ray astronomy in solving problems that occur when accurate agreement is sought with increasingly accurate data is discussed.

  15. Very high energy antineutrinos from photo-disintegration of cosmic ray nuclei

    NASA Astrophysics Data System (ADS)

    Gupta, Nayantara

    2016-02-01

    The photo-disintegration of cosmic ray nuclei by starlight leads to the production of secondary antineutrinos. We have assumed that the flux of the ultrahigh energy cosmic ray nuclei near the Galactic plane region is the same as that observed near the earth and calculated the antineutrino flux produced from their photo-disintegration. The IceCube detector has measured the neutrino/antineutrino flux in the TeV-PeV energy range. Our calculated secondary antineutrino flux in the energy range of 10-100 TeV is found to be much less compared to the flux detected by the IceCube collaboration. The upper limit on the intensity of the radiation field in the extragalactic medium is much lower than that near the Galactic center. If we extend our formalism to the extragalactic medium the contribution from the photo-disintegration of ultrahigh energy cosmic ray heavy nuclei remains insignificant due to their very low flux.

  16. Remarks on the fission barriers of super-heavy nuclei

    NASA Astrophysics Data System (ADS)

    Hofmann, S.; Heinz, S.; Mann, R.; Maurer, J.; Münzenberg, G.; Antalic, S.; Barth, W.; Dahl, L.; Eberhardt, K.; Grzywacz, R.; Hamilton, J. H.; Henderson, R. A.; Kenneally, J. M.; Kindler, B.; Kojouharov, I.; Lang, R.; Lommel, B.; Miernik, K.; Miller, D.; Moody, K. J.; Morita, K.; Nishio, K.; Popeko, A. G.; Roberto, J. B.; Runke, J.; Rykaczewski, K. P.; Scheidenberger, C.; Shaughnessy, D. A.; Stoyer, M. A.; Thörle-Pospiech, P.; Tinschert, K.; Trautmann, N.; Uusitalo, J.; Yeremin, A. V.

    2016-04-01

    Shell-correction energies of super-heavy nuclei are approximated by using Q_{α} values of measured decay chains. Five decay chains were analyzed, which start at the isotopes 285Fl, 294118, 291Lv, 292Lv and 293Lv. The data are compared with predictions of macroscopic-microscopic models. Fission barriers are estimated that can be used to eliminate uncertainties in partial fission half-lives and in calculations of evaporation-residue cross-sections. In that calculations, fission probability of the compound nucleus is a major factor contributing to the total cross-section. The data also provide constraints on the cross-sections of capture and quasi-fission in the entrance channel of the fusion reaction. Arguments are presented that fusion reactions for synthesis of isotopes of elements 118 and 120 may have higher cross-sections than assumed so far.

  17. Charmed Mesons in Nuclei with Heavy-Quark Spin Symmetry

    NASA Astrophysics Data System (ADS)

    Tolos, L.; Garcia-Recio, C.; Nieves, J.; Romanets, O.; Salcedo, L. L.

    2013-08-01

    We study the properties of charmed pseudoscalar and vector mesons in dense matter within a unitary meson-baryon coupled-channel model which incorporates heavy-quark spin symmetry. This is accomplished by extending the SU(3) Weinberg-Tomozawa Lagrangian to incorporate spin-flavor symmetry and implement a suitable flavor symmetry breaking. Several resonances with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with 1/2+ and 3/2+ baryons. Those states are then compared to experimental data as well as theoretical models. Next, Pauli-blocking effects and meson self-energies are introduced in a self-consistent manner to obtain the open-charm meson spectral functions in a dense nuclear environment. We finally discuss the formation of D-mesic nuclei.

  18. Strictly finite-range potential for light and heavy nuclei

    NASA Astrophysics Data System (ADS)

    Salamon, P.; Lovas, R. G.; Betan, R. M. Id; Vertse, T.; Balkay, L.

    2014-05-01

    Strictly finite-range (SFR) potentials are exactly zero beyond their finite range. Single-particle energies and densities, as well as S-matrix pole trajectories, are studied in a few SFR potentials suited for the description of neutrons interacting with light and heavy nuclei. The SFR potentials considered are the standard cutoff Woods-Saxon (CWS) potentials and two potentials approaching zero smoothly: the SV potential introduced by Salamon and Vertse [Phys. Rev. C 77, 037302 (2008), 10.1103/PhysRevC.77.037302] and the SS potential of Sahu and Sahu [Int. J. Mod. Phys. E 21, 1250067 (2012), 10.1142/S021830131250067X]. The parameters of these latter potentials were set so that the potentials may be similar to the CWS shape. The range of the SV and SS potentials scales with the cube root of the mass number of the core like the nuclear radius itself. For light nuclei a single term of the SV potential (with a single parameter) is enough for a good description of the neutron-nucleus interaction. The trajectories are compared with a benchmark for which the starting points (belonging to potential depth zero) can be determined independently. Even the CWS potential is found to conform to this benchmark if the range is identified with the cutoff radius. For the CWS potentials some trajectories show irregular shapes, while for the SV and SS potentials all trajectories behave regularly.

  19. Isotopic stack - measurement of heavy cosmic ray isotopes

    NASA Technical Reports Server (NTRS)

    Beaujean, R.

    1981-01-01

    Heavy cosmic ray nuclei with nuclear charge, Z, equal to or greater than 3 are to be measured using an isotopic stack consisting of passive visual track detectors which remain sensitive throughout the entire mission. The scientific data are stored in latent tracks which are produced by heavy ions and which can be revealed in the investigator's laboratory after recovery. During the mission, only housekeeping data have to be collected. The exposure onboard Spacelab 1 allows the study of the chemical composition and energy spectrum of articles which have energies in the range 20 to 100 million electron volts per atomic mass unit, as well as the isotopic composition of heavy galactic cosmic rays with energies in the range 100 to 1000 million electron volts per atomic mass unit.

  20. Secondary electron background produced by heavy nuclei in a multiwire proportional counter hodoscope

    NASA Technical Reports Server (NTRS)

    Morgan, S. H., Jr.; Watts, J. W., Jr.; Schwille, H.; Pollvogt, U.

    1974-01-01

    The secondary electron background produced by heavy nuclei in a multiwire proportional counter hodoscope is calculated using both a simplified and a more complete Monte Carlo model. These results are compared with experimental data from a small multiwire proportional counter hodoscope operated in a 530 MeV/nucleon accelerator beam of nitrogen nuclei. Estimates of the secondary electron background produced by heavy relativistic nuclei are presented along with the detailed results from calculations of energy deposition in the hodoscope counter cells.

  1. ECCO: Th/U/Pu/Cm Dating of Galactic Cosmic Ray Nuclei

    NASA Technical Reports Server (NTRS)

    Westphal, A. J.; Weaver, B. A.; Solarz, M.; Dominquez, G.; Craig, N.; Adams, J. H.; Barbier, L. M.; Christian, E. R.; Mitchell, J. W.; Binns, W. R.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    The ECCO (Extremely-heavy Cosmic-ray Composition Observer) instrument is one of two instruments which comprise the HNX (Heavy Nuclei Explorer) mission. The principal goal of ECCO is to measure the age of galactic cosmic ray nuclei using the actinides (Th, U, Pu, Cm) as clocks. As a bonus, ECCO will search with unprecedented sensitivity for long-lived elements in the superheavy island of stability. ECCO is an enormous array (23 sq. m) of BP-1 glass track-etch detectors, and is based on the successful flight heritage of the Trek detector which was deployed externally on Mir. We present a description of the instrument, estimates of expected performance, and recent calibrations which demonstrate that the actinides can be resolved from each other with good charge resolution.

  2. Composition and energy spectra of heavy nuclei of unknown origin detected on Skylab

    NASA Technical Reports Server (NTRS)

    Chan, J. H.; Price, P. B.

    1975-01-01

    Lexan track detectors with large collecting power were exposed inside and outside Skylab during late 1973 and early 1974. Steeply falling energy spectra of nuclei with Z greater than or equal to 8 and energies between 10 and 40 MeV were observed at intensities much higher than those observed outside the magnetosphere. Four possible sources (solar flare particles; low-energy cosmic rays; the anomalous component of low-energy cosmic rays; particles trapped in the inner Van Allen belt) are examined using Skylab particle flux data outside the magnetosphere and other measurements. The composition is found to be most consistent with that of the solar corona. It is suggested that heavy solar wind ions enter the magnetosphere, are accelerated, and populate the inner radiation belt.

  3. Medium-heavy nuclei from nucleon-nucleon interactions in lattice QCD

    NASA Astrophysics Data System (ADS)

    Inoue, Takashi; Aoki, Sinya; Charron, Bruno; Doi, Takumi; Hatsuda, Tetsuo; Ikeda, Yoichi; Ishii, Noriyoshi; Murano, Keiko; Nemura, Hidekatsu; Sasaki, Kenji; HAL QCD Collaboration

    2015-01-01

    On the basis of the Brueckner-Hartree-Fock method with the nucleon-nucleon forces obtained from lattice QCD simulations, the properties of the medium-heavy doubly magic nuclei such as 16O and 40Ca are investigated. We found that those nuclei are bound for the pseudoscalar meson mass MPS≃470 MeV. The mass number dependence of the binding energies, single-particle spectra, and density distributions are qualitatively consistent with those expected from empirical data at the physical point, although these hypothetical nuclei at heavy quark mass have smaller binding energies than the real nuclei.

  4. Nuclear isospin asymmetry in α decay of heavy nuclei

    NASA Astrophysics Data System (ADS)

    Shin, Eunkyoung; Lim, Yeunhwan; Hyun, Chang Ho; Oh, Yongseok

    2016-08-01

    The effects of nuclear isospin asymmetry on α -decay lifetimes of heavy nuclei are investigated within various phenomenological models of the nuclear potential for the α particle. We consider the widely used simple square-well potential and Woods-Saxon potential and modify them by including an isospin asymmetry term. We then suggest a model for the potential of the α particle motivated by a microscopic phenomenological approach of the Skyrme force model, which naturally introduces the isospin-dependent form of the nuclear potential for the α particle. The empirical α -decay lifetime formula of Viola and Seaborg [J. Inorg. Nucl. Chem. 28, 741 (1966), 10.1016/0022-1902(66)80412-8] is also modified to include isospin asymmetry effects. The obtained α -decay half-lives are in good agreement with the experimental data, and we find that including the nuclear isospin effects somehow improves the theoretical results for α -decay half-lives. The implications of these results are discussed, and the predictions on the α -decay lifetimes of superheavy elements are also presented.

  5. The decay of hot nuclei

    SciTech Connect

    Moretto, L.G.; Wozniak, G.J.

    1988-11-01

    The formation of hot compound nuclei in intermediate-energy heavy ion reactions is discussed. The statistical decay of such compound nuclei is responsible for the abundant emission of complex fragments and high energy gamma rays. 43 refs., 23 figs.

  6. Anisotropies of ultrahigh energy cosmic ray nuclei diffusing from extragalactic sources

    NASA Astrophysics Data System (ADS)

    Harari, Diego; Mollerach, Silvia; Roulet, Esteban

    2015-09-01

    We obtain the dipolar anisotropies in the arrival directions of ultrahigh energy cosmic ray nuclei diffusing from nearby extragalactic sources. We consider mixed-composition scenarios in which different cosmic ray nuclei are accelerated up to the same maximum rigidity, so that E heavy composition above the ankle. We obtain the anisotropies through Monte Carlo simulations that implement the cosmic ray diffusion in extragalactic turbulent fields as well as the effects of photodisintegrations and other energy losses. Dipolar anisotropies at the level of 5% to 10% at energies ˜10 EeV are predicted for plausible values of the source density and magnetic fields.

  7. Predicted CALET Measurements of Ultra-Heavy Cosmic Ray Abundances

    NASA Astrophysics Data System (ADS)

    Rauch, Brian

    2013-04-01

    The CALorimetric Electron Telescope (CALET), comprised of main calorimeter telescope (CAL) and Gamma-ray Burst Monitor (CGBM), is under construction for launch to the ISS in 2014. CAL consists of a Charge Detector (CHD) with two segmented planes of 1 cm thick plastic scintillator, an Imaging Calorimeter (IMC) with a total of 3 radiation lengths (X0) of tungsten plates read out with 8 planes of interleaved scintillating fibers, and a Total Absorption Calorimeter (TASC) with 27 X0 of lead tungstate (PWO) logs. The primary objectives of CAL are to measure electron energy spectra from 1GeV to 20 TeV, to detect gamma-rays above 10 GeV, and to measure the energy spectra of nuclei from protons through iron up to 1,000 TeV. In this paper we discuss the predicted abundance measurements CAL can make of rare ultra-heavy (UH) nuclei (30 <=Z <=40). In addition to the nuclei that pass within the full CAL geometry, UH nuclei can be resolved using the CHD and top IMC layers without requiring particle energy determination in the TASC in the portion of the ISS 51.6^o inclination orbit where the geomagnetic rigidity cutoffs are above minimum ionization in the scintillator. In 5-years CAL would collect 4-5 times the UH statistics of TIGER.

  8. Super-Heavy Element and Other Exotic Nuclei Research at LLNL

    NASA Astrophysics Data System (ADS)

    Stoyer, M. A.

    2015-11-01

    The experimental nuclear physics group at LLNL is actively investigating exotic nuclei in a variety of regions of the chart of nuclides - from light nuclei to super-heavy elements. The experimental nuclear physics effort at LLNL is centered on investigating nuclei at the extremes--in particular, extremes of spin, isospin, neutron richness, excitation energy, decay and detectability, mass, and stability. This talk will focus on recent heavy and super-heavy element experiments including nuclear structure investigations of the heaviest nuclei. Other areas of research, including radioactive ion beam experiments, trapping experiments, nuclear decay spectroscopy experiments, and rare decay searches, will be discussed as time permits. Recent experimental results on studies of exotic nuclei by scientists at LLNL will be presented.

  9. Heavy particle radioactivity from superheavy nuclei leading to 298114 daughter nuclei

    NASA Astrophysics Data System (ADS)

    Santhosh, K. P.; Priyanka, B.

    2014-09-01

    The feasibility for the alpha decay and the heavy particle decay from the even-even superheavy (SH) nuclei with Z = 116- 124 has been studied within the Coulomb and proximity potential model (CPPM). Our predicted half lives agree well with the values evaluated using the Universal formula for cluster decay (UNIV) of Poenaru et al., the Universal Decay Law (UDL) of Qi et al., and the Scaling Law of Horoi et al. The spontaneous fission half lives of the corresponding parents have also been evaluated using the semi-empirical formula of Santhosh et al. Within our fission model, we have studied the cluster formation probability for various clusters and the maximum cluster formation probability is found for the decay accompanying 298114. In the plots for log10 (T1/2) against the neutron number of the daughter in the corresponding decay, the half life is found to be the minimum for the decay leading to 298114 (Z = 114, N = 184). Most of the predicted half lives are well within the present upper limit for measurements (T1/2 <1030 s) and the computed alpha half lives for 290,292Lv agree well with the experimental data.

  10. Monte Carlo Simulation of Heavy Nuclei Photofission at Intermediate Energies

    SciTech Connect

    Andrade-II, E.; Freitas, E.; Garcia, F.; Tavares, O. A. P.; Duarte, S. B.

    2009-06-03

    A detailed description of photofission process at intermediate energies (200 to 1000 MeV) is presented. The study of the reaction is performed by a Monte Carlo method which allows the investigation of properties of residual nuclei and fissioning nuclei. The information obtained indicate that multifragmentation is negligible at the photon energies studied here, and that the symmetrical fission is dominant. Energy and mass distributions of residual and fissioning nuclei were calculated.

  11. The X-ray spectroscopy of active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Mushotzky, R.

    1985-01-01

    The scientific goals of X-ray spectroscopy of active galactic nuclei are discussed. The underlying energy source, the regions responsible for the optical emission lines, the different types of active galaxies, and cosmology are considered. The requirements for an X-ray mission of broad band width, large collecting area, modest spatial resolution and good spectral resolution are outlined. It is concluded that the ESA XMM mission meets these requirements.

  12. Searches for superheavy elements in nature: Cosmic-ray nuclei; spontaneous fission

    NASA Astrophysics Data System (ADS)

    Ter-Akopian, G. M.; Dmitriev, S. N.

    2015-12-01

    There is little chance that superheavy nuclei with lifetimes of no less than 100 million years are present on the stability island discovered at present. Also, pessimistic are the results of estimates made about their nucleosynthesis in r-process. Nevertheless, the search for these nuclei in nature is justified in view of the fundamental importance of this topic. The first statistically significant data set was obtained by the LDEF Ultra-Heavy Cosmic-Ray Experiment, consisting of 35 tracks of actinide nuclei in galactic cosmic rays. Because of their exceptionally long exposure time in Galaxy, olivine crystals extracted from meteorites generate interest as detectors providing unique data regarding the nuclear composition of ancient cosmic rays. The contemporary searches for superheavy elements in the earth matter rely on knowledge obtained from chemical studies of artificially synthesized superheavy nuclei. New results finding out the chemical behavior of superheavy elements should be employed to obtain samples enriched in their homologues. The detection of rare spontaneous fission events and the technique of accelerator mass spectrometry are employed in these experiments.

  13. High-energy cosmic-ray nuclei from high- and low-luminosity gamma-ray bursts and implications for multimessenger astronomy

    SciTech Connect

    Murase, Kohta; Nagataki, Shigehiro; Ioka, Kunihito; Nakamura, Takashi

    2008-07-15

    Gamma-ray bursts (GRBs) are one of the candidates of ultrahigh-energy (> or approx. 10{sup 18.5} eV) cosmic-ray (UHECR) sources. We investigate high-energy cosmic-ray acceleration including heavy nuclei in GRBs by using Geant 4, and discuss its various implications, taking both high-luminosity (HL) and low-luminosity (LL) GRBs into account. This is because LL GRBs may also make a significant contribution to the observed UHECR flux if they form a distinct population. We show that not only protons, but also heavier nuclei can be accelerated up to ultrahigh energies in the internal, (external) reverse, and forward shock models. We also show that the condition for ultrahigh-energy heavy nuclei such as iron to survive is almost the same as that for {approx}TeV gamma rays to escape from the source and for high-energy neutrinos not to be much produced. The multimessenger astronomy by neutrino and GeV-TeV gamma-ray telescopes such as IceCube and KM3Net, GLAST and MAGIC will be important to see whether GRBs can be accelerators of ultrahigh-energy heavy nuclei. We also demonstrate expected spectra of high-energy neutrinos and gamma rays, and discuss their detectabilities. In addition, we discuss implications of the GRB-UHECR hypothesis. We point out, since the number densities of HL GRBs and LL GRBs are quite different, its determination by UHECR observations is also important.

  14. Heavy nuclei confinement effect in a pulsed light field

    NASA Astrophysics Data System (ADS)

    Starodub, S. S.; Roshchupkin, S. P.

    2011-04-01

    It is a model theoretical work of the applied character in which: "Outside the framework of the dipole approximation (with an accuracy of about v/c) the effective interaction force between stripped uranium nuclei in the presence pulsed field of two laser waves extending towards each other is theoretically studied. It is shown that the effective interaction force between uranium nuclei, can become an attractive force on certain time intervals in the presence of the pulsed laser field. As a result the pulsed laser field can slow down backward motion of nuclei in 7 times."

  15. Cosmic ray nuclei from extragalactic and galactic pulsars

    NASA Astrophysics Data System (ADS)

    Fang, Ke

    2013-02-01

    In an extragalactic newly-born pulsar, nuclei striped off the star surface can be accelerated to extreme energies and leave the source through dense supernova surroundings. The escaped ultrahigh energy cosmic rays can explain both UHE energy spectral and atmospheric depth observations. In addition, assuming that Galactic pulsars accelerate cosmic rays with the same injection composition, very high energy cosmic rays from local pulsars can meet the flux measurements from above the knee to the ankle, and at the same time, agree with the detected composition trend.

  16. X-ray emission from active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Mushotzky, R.

    1985-01-01

    It is often held that the X-ray emission from active galactic nuclei (AGN) arises from a region close to the central energy source. Thus X-ray observations may provide the best constraints on the central engine. In particular, the shape of the X-ray continuum gives information about the mechanism for photon generation, X-ray time variability data can constrain the size and mass of the continuum source, and X-ray occultation data give constraints on the relative sizes of the continuum source and the intervening absorbing material (often assumed to be the broad line clouds). In addition, since a fair fraction of the total energy of an AGN is emitted at X-ray wavelengths, direct measurement of the amount and spectral form of this radiation is important for modeling of the optically emitting clouds.

  17. Introduction to the study of collisions between heavy nuclei

    SciTech Connect

    Bayman, B.F.

    1980-01-01

    Current investigations concerning the collisions of nuclei governed by small de Broglie wavelengths are reviewed. The wave packets localize nuclei in regions small compared to their diameters. Cross sections are examined for potential scattering, elastic scattering, quasi-molecular states, peripheral particle-transfer reactions, fusion, and deep inelastic collisions. Theories of fusion and deep inelastic collisions are summarized. This paper is in the nature of a review-tutorial. 45 references, 51 figures, 2 tables. (RWR)

  18. Light nuclei production in fusion of heavy ions

    SciTech Connect

    Antonenko, N.V.; Ivanova, S.P.; Jolos, R.V.; Scheid, W. Joint Institute for Nuclear Research, 141980 Dubna )

    1994-10-01

    A possible mechanism of the production of light nuclei in fusion reactions is considered. It is shown that the decay of the dinuclear system during its evolution to a compound nucleus yields a substantial rate for the production of light nuclei. The cross section of this process is calculated for the reaction [sup 58]Ni+[sup 58]Ni. The coupling of other modes of motion causes an increase of the asymmetric decay of the dinuclear system.

  19. High-energy multiple muons and heavy primary cosmic-rays

    NASA Technical Reports Server (NTRS)

    Mizutani, K.; Sato, T.; Takahashi, T.; Higashi, S.

    1985-01-01

    Three-dimensional simulations were carried out on high-energy multiple muons. On the lateral spread, the comparison with the deep underground observations indicates that the primary cosmic rays include heavy nuclei of high content. A method to determine the average mass number of primary particles in the energy around 10 to the 15th power eV is suggested.

  20. X-ray laser microscopy of rat sperm nuclei

    SciTech Connect

    Da Silva, L.B. ); Trebes, J.E.; Balhorn, R.; Mrowka, S.; Barbee, T.W.Jr.; Brase, J.; Corzett, M.; Koch, J.A.; Lee, C.; London, R.A.; MacGowan, B.J.; Matthews, D.L.; Stone, G. ); Anderson, E.; Attwood, D.T. ); Gray, J. ); Kern, D. )

    1992-10-09

    The development of high brightness and short pulse width x-ray lasers now offers biologists the possibility of high-resolution imaging of specimens in an aqueous environment without the blurring effects associated with natural motions and chemical erosion. As a step toward developing the capabilities of this type of x-ray microscopy, a tantalum x-ray laser at 44.83 angstrom wavelength was used together with an x-ray zone plate lens to image both unlabeled and selectively gold-labeled dried rat sperm nuclei. The observed images show {approximately}500 angstrom features, illustrate the importance of x-ray microscopy in determining chemical composition, and provide information about the uniformity of sperm chromatin organization and the extent of sperm chromatin hydration.

  1. Production of light nuclei in relativistic heavy-ion collisions

    SciTech Connect

    Barrette, J.; Bellwied, R.; Braun-Munzinger, P.; Cleland, W.E.; Cormier, T.M.; David, G.; Dee, J.; Diebold, G.E.; Dietzsch, O.; Germani, J.V.; Gilbert, S.; Greene, S.V.; Hall, J.R.; Hemmick, T.K.; Herrmann, N.; Hong, B.; Jayananda, K.; Kraus, D.; Kumar, B.S.; Lacasse, R.; Lissauer, D.; Llope, W.J.; Ludlam, T.W.; McCorkle, S.; Majka, R.; Mark, S.K.; Mitchell, J.T.; Muthuswamy, M.; O'Brien, E.; Pruneau, C.; Rotondo, F.S.; Sandweiss, J.; daSilva, N.C.; Sonnadara, U.; Stachel, J.; Takai, H.; Takagui, E.M.; Throwe, T.G.; Wolfe, D.; Woody, C.L.; Xu, N.; Zhang, Y.; Zhang, Z.; Zou, C. Gesellschaft fuer Schwerionenforschung, Darmstadt McGill University, Montreal, Canada H3A University of Pittsburgh, Pittsburgh, Pennsylvania 15260 State University of New York, Stony Brook, New York 11794 University of New Mexico, Albuquerque, New Mexico 87131 University of Sa

    1994-08-01

    We have measured cross sections for the synthesis of nuclei of mass [ital A][le]4 in collisions of 14.6[ital A] GeV/[ital c] [sup 28]Si nuclei with targets of Pb, Cu, and Al. The data are measured at close to center-of-mass rapidities, and are unique in their exploration of the centrality dependence of nucleosynthesis. Simple coalescence models that were used to study nucleosynthesis at lower energies are inadequate for the description of our measurements. Our data and improved models are used to extract parameters related to the size of the interaction volume at freeze-out.

  2. Reactions of Synthesis of Heavy Nuclei Results and Perspectives

    SciTech Connect

    Oganessian, Yu.

    2006-08-14

    The experimental and theoretical results on the properties of the isotopes of superheavy elements, obtained up to now, have made it possible to consider different reactions for the synthesis of heavier nuclei located in the vicinity of the closed proton and neutron shells. It is shown that the advance to the heaviest possible nuclei, for which the microscopic models predict further rise of stability, is inseparably linked to the future investigation of the mechanism of synthesis reactions. Direct and model experiments, aimed at solving this problem, are also discussed.

  3. Neutron flow between nuclei as the principal enhancement mechanism in heavy-ion subbarrier fusion

    SciTech Connect

    Stelson, P.H.

    1988-01-01

    The observed enhanced cross sections for heavy-ion fusion are interpreted with a model in which the near barrier cross sections are dominated by neck formation initiated by neutron flow between the colliding nuclei. The collective properties of the colliding nuclei are then interpreted as a modulation of the thresholds for neck formation and dominate the cross sections in the region far below the barrier. 12 refs., 12 figs., 2 tabs.

  4. Structure properties of medium and heavy exotic nuclei

    NASA Astrophysics Data System (ADS)

    Gaidarov, M. K.

    2012-09-01

    Investigations of important characteristics of the structure of nuclei near drip-lines in coordinate and momentum space have been performed. The charge form factors, charge and matter densities and the corresponding rms radii for even-even isotopes of Ni, Kr, and Sn are calculated in the framework of deformed self-consistent mean field Skyrme DDHF+BCS method. The resulting charge radii and neutron skin thicknesses of these nuclei are compared with available experimental data, as well as with other theoretical predictions. The formation of a neutron skin is analyzed in terms of various definitions. Its correlation with the nuclear symmetry energy is studied within the coherent density fluctuation model using the symmetry energy as a function of density within the Brueckner energy-density functional. The nucleon momentum distributions for the same isotopic chains of neutron-rich nuclei are studied in the framework of the same mean-field method, as well as of theoretical correlation methods based on light-front dynamics and local density approximation. The isotopic sensitivities of the calculated neutron and proton momentum distributions are investigated together with the effects of nucleon correlations and deformation of nuclei.

  5. Role of compound nuclei in intermediate-energy heavy-ion reactions

    SciTech Connect

    Moretto, L.G.; Wozniak, G.J.

    1988-05-01

    Hot compound nuclei are frequently produced in intermediate-energy reactions through a variety of processes. Their decay is shown to be an important and at times dominant source of complex fragments, high energy-gamma rays, and even pions.

  6. Nucleosynthesis of neutron-rich heavy nuclei during explosive helium burning in massive stars

    NASA Technical Reports Server (NTRS)

    Blake, J. B.; Woosley, S. E.; Weaver, T. A.; Schramm, D. N.

    1981-01-01

    The production of heavy nuclei during explosive helium burning has been calculated using a hydrodynamical model of a 15-solar mass (Type II) supernova and an n-process nuclear reaction network. It is found that the resulting neutron-rich heavy nuclei are not produced in the relative abundances of solar-system r-process material, especially in the vicinity of Pt, nor are any actinides produced. These deficiencies reflect an inadequate supply of neutrons. However, some neutron-rich isotopes, normally associated with the r-process, are produced which may be significant for the production of isotopic anomalies in meteorites.

  7. X-Ray Reprocessing in Active Galactic Nuclei

    NASA Technical Reports Server (NTRS)

    Begelman, Mitchell C.

    2004-01-01

    This is the final report for research entitled "X-ray reprocessing in active galactic nuclei," into X-ray absorption and emission in various classes of active galaxy via X-ray spectral signatures. The fundamental goal of the research was to use these signatures as probes of the central engine structure and circumnuclear environment of active galactic nuclei. The most important accomplishment supported by this grant involved the detailed analysis and interpretation of the XMM data for the bright Seyfert 1 galaxy MCG-6-30-15. This work was performed by Drs. Christopher Reynolds and Mitchell Begelman in collaboration with Dr. Jorn Wilms (University of Tubingen, Germany; PI of the XMM observation) and other European scientists. With XMM we obtained medium resolution X-ray spectra of unprecedented quality for this Seyfert galaxy. Modeling the X-ray spectrum within the framework of accretion disk reflection models produced the first evidence for energy extraction from the spin of a black hole. Specifically, we found that the extreme gravitational redshifts required to explain the X-ray spectrum suggests that the bulk of the energy dissipation is concentrated very close to the black hole, in contrast with the expectations of any pure accretion disk model. In a second paper we addressed the low- energy spectral complexity and used RXTE specta to pin down the high-energy spectral index, thus firming up our initial interpretation. Additionally, we carried out detailed spectral and variability analyses of a number of Seyfert and radio galaxies (e.g., NGC 5548 and 3C 111) and developed general techniques that will be useful in performing X-ray reverberation mapping of accretion disks in AGN, once adequate data becomes available. A list of papers supported by this research is included.

  8. Studies of the Shapes of Heavy Nuclei at ISOLDE

    NASA Astrophysics Data System (ADS)

    Butler, Peter A.

    For certain combinations of protons and neutrons there is a theoretical expectation that the shape of nuclei can assume octupole deformation, which would give rise to reflection asymmetry or a "pear-shape" in the intrinsic frame, either dynamically (octupole vibrations) or statically (permanent octupole deformation). In this talk I will briefly review the historic evidence for reflection asymmetry in nuclei and describe how recent experiments carried out at REX-ISOLDE have constrained nuclear theory and how they contribute to tests of extensions of the Standard Model. I will also discuss future prospects for measuring nuclear shapes from Coulomb Excitation: experiments are being planned that will exploit beams from HIE-ISOLDE that are cooled in the TSR storage ring and injected into a solenoidal spectrometer similar to the HELIOS device developed at the Argonne National Laboratory.

  9. One-quasiparticle states in odd-Z heavy nuclei

    SciTech Connect

    Adamian, G. G.; Antonenko, N. V.; Kuklin, S. N.; Scheid, W.

    2010-11-15

    The isotopic dependencies of one-quasiparticle states in Es and Md are treated. In {sup 253,255}Lr, the energies of the lowest one-quasiproton states are calculated. The one-quasiparticle isomer states are revealed in the nuclei of an {alpha}-decay chain starting from {sup 269}Rg. The {alpha} decays from some isomer states are predicted. The population of isomer states in the complete fusion reactions is discussed.

  10. Diffuse γ-ray emission from misaligned active galactic nuclei

    SciTech Connect

    Di Mauro, M.; Donato, F.; Calore, F.; Ajello, M.; Latronico, L.

    2014-01-10

    Active galactic nuclei (AGNs) with jets seen at small viewing angles are the most luminous and abundant objects in the γ-ray sky. AGNs with jets misaligned along the line of sight appear fainter in the sky but are more numerous than the brighter blazars. We calculate the diffuse γ-ray emission due to the population of misaligned AGNs (MAGNs) unresolved by the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (Fermi). A correlation between the γ-ray luminosity and the radio-core luminosity is established and demonstrated to be physical by statistical tests, as well as compatible with upper limits based on Fermi-LAT data for a large sample of radio-loud MAGNs. We constrain the derived γ-ray luminosity function by means of the source-count distribution of the radio galaxies detected by the Fermi-LAT. We finally calculate the diffuse γ-ray flux due to the whole MAGN population. Our results demonstrate that MAGNs can contribute from 10% up to nearly the entire measured isotropic gamma-ray background. We evaluate a theoretical uncertainty on the flux of almost an order of magnitude.

  11. Diffuse γ-Ray Emission from Misaligned Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Di Mauro, M.; Calore, F.; Donato, F.; Ajello, M.; Latronico, L.

    2014-01-01

    Active galactic nuclei (AGNs) with jets seen at small viewing angles are the most luminous and abundant objects in the γ-ray sky. AGNs with jets misaligned along the line of sight appear fainter in the sky but are more numerous than the brighter blazars. We calculate the diffuse γ-ray emission due to the population of misaligned AGNs (MAGNs) unresolved by the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (Fermi). A correlation between the γ-ray luminosity and the radio-core luminosity is established and demonstrated to be physical by statistical tests, as well as compatible with upper limits based on Fermi-LAT data for a large sample of radio-loud MAGNs. We constrain the derived γ-ray luminosity function by means of the source-count distribution of the radio galaxies detected by the Fermi-LAT. We finally calculate the diffuse γ-ray flux due to the whole MAGN population. Our results demonstrate that MAGNs can contribute from 10% up to nearly the entire measured isotropic gamma-ray background. We evaluate a theoretical uncertainty on the flux of almost an order of magnitude.

  12. The α decay spectroscopic factor of heavy and superheavy nuclei

    NASA Astrophysics Data System (ADS)

    Seif, W. M.

    2013-10-01

    The spectroscopic factor which refers to the preformation probability of an α cluster inside parent radioactive nuclei is investigated. The study is based on the cluster model of α decay that is extended to account for the deformation degrees of freedom. The calculations are carried out for 179 even(Z)-even(N) parent nuclei in the mass region of A = 144-294. Taking into account the deformations of daughter nuclei, the semi-microscopic calculations of the α-daughter interaction potential are performed using the Hamiltonian energy density approach in terms of the SLy4 Skyrme-like effective interaction. The calculated potential is then implemented to find both the assault frequency and the penetration probability of the α particle by means of the Wentzel-Kramers-Brillouin approximation at different orientations of the deformed daughter. By averaging the obtained decay widths over different orientations, the half-lives of the mentioned α decays are then estimated. Taking into account the errors on both the released energy and the experimental half-life times, the extracted half-lives are employed in turn to deduce the α spectroscopic factor. The results show a periodic behaviour of the spectroscopic factor as a function of the charge and neutron numbers characterized by several local maxima and minima. The predicted minima are mainly related to the proton and neutron shell and subshell closures. In addition to the well-known closed shells of the nucleonic numbers 50, 82, and 126, the obtained values of the spectroscopic factor give some evidence for the presence of closed subshells of nucleonic numbers 70, 102 (104) and 152 (150). A simple formula is suggested to roughly estimate the spectroscopic factor in terms of the numbers of protons and neutrons of the parent nucleus outside its closed shells. The parameters of this formula are fitted to the deduced values of the spectroscopic factor.

  13. Symmetries in heavy nuclei and the proton-neutron interaction

    SciTech Connect

    Casten, R.F.

    1986-01-01

    The Interacting Boson Approximation (IBA) nuclear structure model can be expressed in terms of the U(6) group, and thereby leads to three dynamical symmetries (or group chains) corresponding to different nuclear coupling schemes and geometrical shapes. The status of the empirical evidence for these three symmetries is reviewed, along with brief comments on the possible existence of supersymmetries in nuclei. The relationships between these symmetries, the nuclear phase transitional regions linking them, and the residual proton-neutron interaction are discussed in terms of a particularly simple scheme for parameterizing the effects of that interaction. 34 refs., 15 figs.

  14. Manifestation of cluster effects in collective octupole and superdeformed states of heavy nuclei.

    NASA Astrophysics Data System (ADS)

    Shneidman, T. M.; Adamian, G. G.; Antonenko, N. V.; Jolos, R. V.

    2016-06-01

    The effects of reflection-asymmetric deformation on the properties of the low-lying negative-parity collective states and superdeformed states of heavy nuclei are analyzed basing on dinuclear model. The results of consideration of the alternating parity bands in actinides and the superdeformed bands in 60Zn, Pb and Hg isotopes are discussed.

  15. Projected shell model for Gamow-Teller transitions in heavy, deformed nuclei

    NASA Astrophysics Data System (ADS)

    Wang, Long-Jun; Sun, Yang; Gao, Zao-Chun; Kiran Ghorui, Surja

    2016-02-01

    Calculations of Gamow-Teller (GT) transition rates for heavy, deformed nuclei, which are useful input for nuclear astrophysics studies, are usually done with the quasiparticle random-phase approximation. We propose a shell-model method by applying the Projected Shell Model (PSM) based on deformed bases. With this method, it is possible to perform a state-by-state calculation for nuclear matrix elements for β-decay and electron-capture in heavy nuclei. Taking β- decay from 168Dy to 168Ho as an example, we show that the known experimental B(GT) from the ground state of the mother nucleus to the low-lying states of the daughter nucleus could be well described. Moreover, strong transitions to high-lying states are predicted to occur, which may considerably enhance the total decay rates once these nuclei are exposed to hot stellar environments.

  16. Calculations of {alpha}-decay half-lives for heavy and superheavy nuclei

    SciTech Connect

    Qian Yibin; Ni Dongdong; Ren, Zhongzhou

    2011-04-15

    Systematic calculations on the {alpha}-decay half-lives of heavy and superheavy nuclei are performed within a deformed version of the cluster model, using the modified two-potential approach. The deformed Woods-Saxon potential is employed to calculate the {alpha}-decay width through a deformed barrier. For comparison the calculated {alpha}-decay half-lives in the empirical relations are also presented. The present study is initially restricted to even-even nuclei in the heavy mass region with N>126. Then the study is extended to the recently observed heaviest nuclei, including synthesized superheavy elements and isotopes. The {alpha}-decay half-lives obtained are found to be in good agreement with the experimental data.

  17. Active galactic nuclei at gamma-ray energies

    NASA Astrophysics Data System (ADS)

    Dermer, Charles Dennison; Giebels, Berrie

    2016-06-01

    Active Galactic Nuclei can be copious extragalactic emitters of MeV-GeV-TeV γ rays, a phenomenon linked to the presence of relativistic jets powered by a super-massive black hole in the center of the host galaxy. Most of γ-ray emitting active galactic nuclei, with more than 1500 known at GeV energies, and more than 60 at TeV energies, are called "blazars". The standard blazar paradigm features a jet of relativistic magnetized plasma ejected from the neighborhood of a spinning and accreting super-massive black hole, close to the observer direction. Two classes of blazars are distinguished from observations: the flat-spectrum radio-quasar class (FSRQ) is characterized by strong external radiation fields, emission of broad optical lines, and dust tori. The BL Lac class (from the name of one of its members, BL Lacertae) corresponds to weaker advection-dominated flows with γ-ray spectra dominated by the inverse Compton effect on synchrotron photons. This paradigm has been very successful for modeling the broadband spectral energy distributions of blazars. However, many fundamental issues remain, including the role of hadronic processes and the rapid variability of a few FSRQs and several BL Lac objects whose synchrotron spectrum peaks at UV or X-ray frequencies. A class of γ-ray-emitting radio galaxies, which are thought to be the misaligned counterparts of blazars, has emerged from the results of the Fermi-Large Area Telescope and of ground-based Cherenkov telescopes. Soft γ-ray emission has been detected from a few nearby Seyfert galaxies, though it is not clear whether those γ rays originate from the nucleus. Blazars and their misaligned counterparts make up most of the ≳100 MeV extragalactic γ-ray background (EGB), and are suspected of being the sources of ultra-high energy cosmic rays. The future "Cherenkov Telescope Array", in synergy with the Fermi-Large Area Telescope and a wide range of telescopes in space and on the ground, will write the next chapter

  18. Detection of ultra rare α decays of super heavy nuclei

    NASA Astrophysics Data System (ADS)

    Tsyganov, Yuri S.

    2007-04-01

    Three approaches to the measurement of a rare α decaying products produced in heavy-ion induced nuclear reactions are described. One is based on a chemical extraction and following deposition of the nuclides under investigation onto the surface of the detector, whereas the second one is associated with long-lived products implanted into silicon detectors by using the electromagnetic separation technique. The third approach relates with an application of real-time mode detection of correlated energy-time-position recoil-α sequences from 48Ca induced nuclear reactions with actinide targets, like 242,244Pu, 245,248Cm, 239Am and 249Cf. Namely with this technique, it has became possible to provide a radical suppression of backgrounds in the full fusion (3-5n) reactions aimed to the synthesis of super heavy elements with Z=113-116.

  19. Proximity potential for heavy ion reactions on deformed nuclei

    SciTech Connect

    Baltz, A. J.; Bayman, B. F.

    1982-01-01

    The usual treatment of the deformed optical model for analysis of heavy ion induced inelastic scattering data involves a deformed (target) radius, a spherical (projectile) radius and a potential strength dependent on the surface separation along the line between the two centers. Several authors using various approaches have shown that this center line potential is geometrically inadequate especially for description of higher L deformation parameters probed in heavy ion induced inelastic scattering experiments. A quantitatively adequate form of the deformed proximity potential suitable for use with a coupled channels reaction code in the analysis of inelastic scattering data above the Coulomb barrier is described. A major objective is to be able to extract reliably higher deformed multipole moments from such data. The deformed potential calculated in the folding model will serve as a geometrically exact benchmark to evaluate the accuracy of the proximity potential prescriptions. (WHK)

  20. α-DECAY Properties of Heavy and Superheavy Nuclei

    NASA Astrophysics Data System (ADS)

    Zhang, H. F.

    2013-11-01

    The experimental investigation cannot presently distinguish explicitly whether the α particle is preformed in mother nucleus or it is formed during penetrating of the potential barrier. Consequently, the α-decay has been mainly described using the cluster-like theories and the fission-like theories. In any way, the assault frequency plays a pivotal role in the two different decay modes. A microscopic approach is adopted to estimate the assault frequency and the results are consistent with the assault frequency extracted within the cluster-like model, which suggests that the α-decay is rather a radioactive emission process of a cluster preformed in the nucleus but before the potential barrier penetration. The α-decay half-life are estimated in the framework of the preformed cluster-like model to explore the island of stability of superheavy nuclei.

  1. Use of relativistic rise in ionization chambers for measurement of high energy heavy nuclei

    NASA Technical Reports Server (NTRS)

    Barthelmy, S. D.; Israel, M. H.; Klarmann, J.; Vogel, J. S.

    1983-01-01

    A balloon-borne instrument has been constructed to measure the energy spectra of cosmic-ray heavy nuclei in the range of about 0.3 to about 100 GeV/amu. It makes use of the relativistic rise portion of the Bethe-Bloch curve in ionization chambers for energy determination in the 10- to 100-GeV/amu interval. The instrument consists of six layers of dual-gap ionization chambers for energy determination above 10 GeV/amu. Charge is determined with a NE114 scintillator and a Pilot 425 plastic Cerenkov counter. A CO2 gas Cerenkov detector (1 atm; threshold of 30 GeV/amu) calibrates the ion chambers in the relativistic rise region. The main emphasis of the instrument is the determination of the change of the ratio of Iron (26) to the Iron secondaries (21-25) in the energy range of 10 to 100 GeV/amu. Preliminary data from a balloon flight in the fall of 1982 from Palestine, TX is presented.

  2. Muonic x-ray study of the even Os nuclei

    NASA Astrophysics Data System (ADS)

    Hoehn, M. V.; Shera, E. B.; Wohlfahrt, H. D.; Yamazaki, Y.; Steffen, R. M.; Sheline, R. K.

    1981-10-01

    Precision measurements have been made of the muonic x-ray spectra of the transitional nuclei 186,188,190,192Os. Equivalent Barrett radii and isotope shifts have been determined, as have isomer shifts of the first excited 2+ states. These results are compared with other experiments and with theoretical calculations. The systematics of isotope shifts in the deformed nuclei are also discussed. Generalized E 2 moments of the charge distribution have been extracted in a nearly model-independent way and conventional electromagnetic moments have been deduced by assuming a specific transition charge density model. The latter are in good agreement with recent calculations of both the interacting boson approximation and the boson expansion theory. However, a serious discrepancy in the values of the quadrupole moments determined from the muonic and Coulomb excitation experiments is apparent. The model dependence of the muonic results (including the effect of a triaxial model charge distribution) is explored as a possible cause of the discrepancy; however, no effect large enough to explain the discrepancy is found. Furthermore, no feature of the muonic spectra was found which could be used to distinguish between a triaxial and an axially symmetric charge distribution. NUCLEAR STRUCTURE 186,188,190,192Os; measured muonic x-ray spectra; deduced monopole and quadrupole charge parameters, isotope and isomer shifts.

  3. What obscures low-X-ray-scattering active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Hönig, S. F.; Gandhi, P.; Asmus, D.; Mushotzky, R. F.; Antonucci, R.; Ueda, Y.; Ichikawa, K.

    2014-02-01

    X-ray surveys have revealed a new class of active galactic nuclei (AGN) with a very low observed fraction of scattered soft X-rays, fscat <0.5 per cent. Based on X-ray modelling, these `X-ray new-type', or low observed X-ray-scattering (hereafter, `low-scattering') sources have been interpreted as deeply buried AGN with a high covering factor of gas. In this paper, we address the questions whether the host galaxies of low-scattering AGN may contribute to the observed X-ray properties, and whether we can find any direct evidence for high covering factors from the infrared (IR) emission. We find that X-ray low-scattering AGN are preferentially hosted by highly inclined galaxies or merger systems as compared to other Seyfert galaxies, increasing the likelihood that the line of sight towards the AGN intersects with high columns of host-galactic gas and dust. Moreover, while a detailed analysis of the IR emission of low-scattering AGN ESO 103-G35 remains inconclusive, we do not find any indication of systematically higher dust covering factors in a sample of low-scattering AGN based on their IR emission. For ESO 103-G35, we constrained the temperature, mass and location of the IR emitting dust which is consistent with expectations for the dusty torus. However, a deep silicate absorption feature probably from much cooler dust suggests an additional screen absorber on larger scales within the host galaxy. Taking these findings together, we propose that the low fscat observed in low-scattering AGN is not necessarily the result of circumnuclear dust but could originate from interference of host-galactic gas with a column density of the order of 1022 cm-2 with the line of sight. We discuss implications of this hypothesis for X-ray models, high-ionization emission lines and observed star formation activity in these objects.

  4. Analysis of quasifission competition in fusion reactions forming heavy nuclei

    NASA Astrophysics Data System (ADS)

    Hammerton, Kalee; Kohley, Zachary; Morrissey, Dave; Wakhle, Aditya; Stiefel, Krystin; Hinde, David; Dasgupta, Mahananda; Williams, Elizabeth; Simenel, Cedric; Carter, Ian; Cook, Kaitlin; Jeung, Dongyun; Luong, Duc Huy; McNeil, Steven; Palshetkar, Chandani; Rafferty, Dominic

    2015-10-01

    Heavy-ion fusion reactions have provided a mechanism for the production of superheavy elements allowing for the extension of both the periodic table and chart of the nuclides. However, fusion of the projectile and target, forming a compound nucleus, is hindered by orders of magnitude by the quasifission process in heavy systems. In order to fully understand this mechanism, and make accurate predictions for superheavy element production cross sections, a clear description of the interplay between the fusion-fission and quasifission reaction channels is necessary. The mass-angle distributions of fragments formed in 8 different Cr + W reactions were measured at the Australia National University in order to explore the N/Z dependence of the quasifission process. Two sets of data were measured: one at a constant energy relative to the fusion barrier and one at a constant compound nucleus excitation energy. The results of this analysis will provide insight into the effect of using more neutron-rich beams in superheavy element production reactions.

  5. NEW EQUATIONS OF STATE BASED ON THE LIQUID DROP MODEL OF HEAVY NUCLEI AND QUANTUM APPROACH TO LIGHT NUCLEI FOR CORE-COLLAPSE SUPERNOVA SIMULATIONS

    SciTech Connect

    Furusawa, Shun; Yamada, Shoichi; Sumiyoshi, Kohsuke; Suzuki, Hideyuki

    2013-08-01

    We construct new equations of state for baryons at subnuclear densities for the use in core-collapse simulations of massive stars. The abundance of various nuclei is obtained together with thermodynamic quantities. A model free energy is constructed, based on the relativistic mean field theory for nucleons and the mass formula for nuclei with the proton number up to {approx}1000. The formulation is an extension of the previous model, in which we adopted the liquid drop model to all nuclei under the nuclear statistical equilibrium. We reformulate the new liquid drop model so that the temperature dependences of bulk energies could be taken into account. Furthermore, we extend the region in the nuclear chart, in which shell effects are included, by using theoretical mass data in addition to experimental ones. We also adopt a quantum-theoretical mass evaluation of light nuclei, which incorporates the Pauli- and self-energy shifts that are not included in the ordinary liquid drop model. The pasta phases for heavy nuclei are taken into account in the same way as in the previous model. We find that the abundances of heavy nuclei are modified by the shell effects of nuclei and temperature dependence of bulk energies. These changes may have an important effect on the rates of electron captures and coherent neutrino scatterings on nuclei in supernova cores. The abundances of light nuclei are also modified by the new mass evaluation, which may affect the heating and cooling rates of supernova cores and shocked envelopes.

  6. Two-neutron transfer reactions with heavy-deformed nuclei

    SciTech Connect

    Price, C.; Landowne, S.; Esbensen, H.

    1988-01-01

    In a recent communication we pointed out that one can combine the macroscopic model for two-particle transfer reactions on deformed nuclei with the sudden limit approximation for rotational excitation, and thereby obtain a practical method for calculating transfer reactions leading to high-spin states. As an example, we presented results for the reaction WSDy(VYNi,WNi) WDy populating the ground-state rotational band up to the spin I = 14 state. We have also tested the validity of the sudden limit for the inelastic excitation of high spin states and we have noted how the macroscopic model may be modified to allow for more microscopic nuclear structure effects in an application to diabolic pair-transfer processes. This paper describes our subsequent work in which we investigated the systematic features of pair-transfer reactions within the macroscopic model by using heavier projectiles to generate higher spins and by decomposing the cross sections according to the multipolarity of the transfer interaction. Particular attention is paid to characteristic structures in the angular distributions for the lower spin states and how they depend on the angular momentum carried by the transferred particles. 11 refs., 3 figs.

  7. Symmetry-dictated trucation: Solutions of the spherical shell model for heavy nuclei

    SciTech Connect

    Guidry, M.W. |

    1992-12-31

    Principles of dynamical symmetry are used to simplify the spherical shell model. The resulting symmetry-dictated truncation leads to dynamical symmetry solutions that are often in quantitative agreement with a variety of observables. Numerical calculations, including terms that break the dynamical symmetries, are shown that correspond to shell model calculations for heavy deformed nuclei. The effective residual interaction is simple, well-behaved, and can be determined from basic observables. With this approach, we intend to apply the shell model in systematic fashion to all nuclei. The implications for nuclear structure far from stability and for nuclear masses and other quantities of interest in astrophysics are discussed.

  8. Competition between complete fusion and quasifission in reactions with heavy nuclei

    SciTech Connect

    Antonenko, N. V.; Scheid, W.; Adamian, G. G.; Volkov, V. V.

    1998-02-15

    A model based on the dinuclear system concept is suggested for the calculation of the competition between complete fusion and quasifission in reactions with heavy nuclei. The fusion rate through the inner fusion barrier in mass asymmetry is found by using the Kramers-type expression. The calculated cross sections for the heaviest nuclei are in a good agreement with the experimental data. The experimentally observed rapid fall-off of the cross section of the cold fusion with increasing charge number Z of the compound nucleus is explained.

  9. Science requirements for Heavy Nuclei Collection (HNC) experiment on NASA Long Duration Exposure Facility (LDEF) Mission 2

    NASA Technical Reports Server (NTRS)

    Price, P. Buford

    1991-01-01

    The Heavy Nuclei Collection (HNC) is a passive array of stacks of a special glass, 14 sheets thick, that record tracks of ultraheavy cosmic rays for later readout by automated systems on Earth. The primary goal is to determine the relative abundances of both the odd- and even-Z cosmic rays with Z equal to or greater than 50 with statistics a factor at least 60 greater than obtained in HEAO-3 and to obtain charge resolution at least as good as 0.25 charge unit. The secondary goal is to search for hypothetical particles such as superheavy elements. The HNC detector array will have a cumulative collection power equivalent to flying 32 sq m of detectors in space for 4 years. The array will be flown as a free-flight spacecraft and/or attached to Space Station Freedom.

  10. Neutron productions in the fragmentation of relativistic heavy nuclei and formation of a beam of high-energy neutrons

    NASA Astrophysics Data System (ADS)

    Yurevich, V. I.

    2016-03-01

    The production of quasimonoenergetic high-energy neutrons at zero angle (0°) in the spallation of relativistic heavy nuclei is discussed by considering the example of the interaction of lead nuclei with light target nuclei. It is shown that this process can be used to generate a beam of high-energy neutrons at existing heavy ion accelerators. At the same time, itmay lead to the appearance of a parasitic neutron beam because of the interaction of the heavy-ion beam used with beam line and experimental setup materials.

  11. Bridging the nuclear structure gap between stable and super heavy nuclei.

    SciTech Connect

    Seweryniak, D.; Khoo, T. L.; Ahmad, I.; Kondev, F. G.; Robinson, A.; Back, B. B.; Carpenter, M. P.; Davids, C. N.; Greene, J. P.; Gros, S.; Janssens, R. V. F.; Lauritsen, T.; Lister, C. J.; McCutchan, E. A.; Peterson, D.; Zhu, S. F.; Physics; Univ. of York; Univ. of Massachusetts at Lowell; Japan Atomic Energy Agency; Univ. of Jyvaskyla; CSNSM Orsay; Yale Univ.; Univ. of Liverpool; RIKEN; Univ. of Maryland; Univ. of Notre Dame

    2010-01-01

    Due to recent advances in detection techniques, excited states in several trans-fermium nuclei were studied in many laboratories worldwide, shedding light on the evolution of nuclear structure between stable nuclei and the predicted island of stability centered around spherical magic numbers. In particular, studies of K-isomers around the Z=100 and N=152 deformed shell closures extended information on the energies of Nilsson orbitals at the Fermi surface. Some of these orbitals originate from spherical states, which are relevant to the magic gaps in super-heavy nuclei. The single-particle energies can be used to test various theoretical predictions and aid in extrapolations towards heavier systems. So far, the Woods-Saxon potential reproduces the data best, while self-consistent approaches miss some of the observed features, indicating a need to modify the underlying effective nucleon-nucleon interactions.

  12. Production of heavy neutron-rich nuclei in transfer reactions within the dinuclear system model

    NASA Astrophysics Data System (ADS)

    Zhu, Long; Feng, Zhao-Qing; Zhang, Feng-Shou

    2015-08-01

    The dynamics of nucleon transfer processes in heavy-ion collisions is investigated within the dinuclear system model. The production cross sections of nuclei in the reactions 136Xe+208Pb and 238U+248Cm are calculated, and the calculations are in good agreement with the experimental data. The transfer cross sections for the 58Ni+208Pb reaction are calculated and compared with the experimental data. We predict the production cross sections of neutron-rich nuclei 165-168 Eu, 169-173 Tb, 173-178 Ho, and 181-185Yb based on the reaction 176Yb+238U. It can be seen that the production cross sections of the neutron-rich nuclei 165Eu, 169Tb, 173Ho, and 181Yb are 2.84 μb, 6.90 μb, 46.24 μb, and 53.61 μb, respectively, which could be synthesized in experiment.

  13. Influence of shell effects on the formation of light nuclei in collisions of heavy ions

    SciTech Connect

    Antonenko, N.V.; Dzholos, R.V. )

    1989-07-01

    Various approaches to calculation of the coefficients of the transport equation which describes the process of multinucleon transfers, are analyzed. It is shown that, without resorting to the averaging of matrix elements over many shell configurations, one can obtain expressions for transition probabilities that include the effects of nuclear shell structure. On this basis, the yield of light nuclei in reactions induced by heavy ions is studied in the framework of the degenerate-shell model. The calculations, which are carried out on the assumption that the wave functions of high-lying one-particle states of the system are not concentrated in one nucleus but are distributed over the two nuclei proportionally to their volumes, lead to an appreciable increase of the yield of light elements as compared to calculations in which one-particle states are assumed to belong to only one of the nuclei forming the double system.

  14. Unwrapping the X-ray spectra of active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Reynolds, C. S.

    2016-05-01

    Active galactic nuclei (AGN) are complex phenomena. At the heart of an AGN is a relativistic accretion disk around a spinning supermassive black hole (SMBH) with an X-ray emitting corona and, sometimes, a relativistic jet. On larger scales, the outer accretion disk and molecular torus act as the reservoirs of gas for the continuing AGN activity. And on all scales from the black hole outwards, powerful winds are seen that probably affect the evolution of the host galaxy as well as regulate the feeding of the AGN itself. In this review article, we discuss how X-ray spectroscopy can be used to study each of these components. We highlight how recent measurements of the high-energy cutoff in the X-ray continuum by NuSTAR are pushing us to conclude that X-ray coronae are radiatively-compact and have electron temperatures regulated by electron-positron pair production. We show that the predominance of rapidly-rotating objects in current surveys of SMBH spin is entirely unsurprising once one accounts for the observational selection bias resulting from the spin-dependence of the radiative efficiency. We review recent progress in our understanding of fast (v˜ (0.1-0.3)c, highly-ionized (mainly visible in Fe XXV and Fe XXVI lines), high-column density winds that may dominate quasar-mode galactic feedback. Finally, we end with a brief look forward to the promise of Astro-H and future X-ray spectropolarimeters.

  15. A mechanism for the abundance enhancements of heavy nuclei in solar flare particle events

    NASA Technical Reports Server (NTRS)

    Cartwright, B. G.; Mogro-Campero, A.

    1973-01-01

    A mechanism is proposed to account for the recently reported abundance enhancements of heavy nuclei in solar flares. The mechanism requires two acceleration stages for its operation: First, fully stripped ions are accelerated to suprathermal energies, and subsequently, a fraction of these ions are Fermi accelerated to higher energies. It is shown that because injection into Fermi acceleration is rigidity dependent and the ions may pick up electrons during transport to the Fermi acceleration region, an enhancement of the abundances of heavy nuclei can occur. The degree of the enhancement depends on a number of factors particular to each flare, so that the degree of enhancement may be variable from flare to flare, or may be a function of time within a given flare. In some flares, conditions may be such that no enhancement would be expected.

  16. Nonlinear ion-acoustic waves in a degenerate plasma with nuclei of heavy elements

    SciTech Connect

    Hossen, M. A. Mamun, A. A.

    2015-10-15

    The ion-acoustic (IA) solitary waves propagating in a fully relativistic degenerate dense plasma (containing relativistic degenerate electron and ion fluids, and immobile nuclei of heavy elements) have been theoretically investigated. The relativistic hydrodynamic model is used to derive the Korteweg-de Vries (K-dV) equation by the reductive perturbation method. The stationary solitary wave solution of this K-dV equation is obtained to characterize the basic features of the IA solitary structures that are found to exist in such a degenerate plasma. It is found that the effects of electron dynamics, relativistic degeneracy of the plasma fluids, stationary nuclei of heavy elements, etc., significantly modify the basic properties of the IA solitary structures. The implications of this results in astrophysical compact objects like white dwarfs are briefly discussed.

  17. Nonlinear ion-acoustic waves in a degenerate plasma with nuclei of heavy elements

    NASA Astrophysics Data System (ADS)

    Hossen, M. A.; Mamun, A. A.

    2015-10-01

    The ion-acoustic (IA) solitary waves propagating in a fully relativistic degenerate dense plasma (containing relativistic degenerate electron and ion fluids, and immobile nuclei of heavy elements) have been theoretically investigated. The relativistic hydrodynamic model is used to derive the Korteweg-de Vries (K-dV) equation by the reductive perturbation method. The stationary solitary wave solution of this K-dV equation is obtained to characterize the basic features of the IA solitary structures that are found to exist in such a degenerate plasma. It is found that the effects of electron dynamics, relativistic degeneracy of the plasma fluids, stationary nuclei of heavy elements, etc., significantly modify the basic properties of the IA solitary structures. The implications of this results in astrophysical compact objects like white dwarfs are briefly discussed.

  18. Level densities of heavy nuclei in the shell model Monte Carlo approach

    NASA Astrophysics Data System (ADS)

    Alhassid, Y.; Bertsch, G. F.; Gilbreth, C. N.; Nakada, H.; Özen, C.

    2016-06-01

    Nuclear level densities are necessary input to the Hauser-Feshbach theory of compound nuclear reactions. However, the microscopic calculation of level densities in the presence of correlations is a challenging many-body problem. The configurationinteraction shell model provides a suitable framework for the inclusion of correlations and shell effects, but the large dimensionality of the many-particle model space has limited its application in heavy nuclei. The shell model Monte Carlo method enables calculations in spaces that are many orders of magnitude larger than spaces that can be treated by conventional diagonalization methods and has proven to be a powerful tool in the microscopic calculation of level densities. We discuss recent applications of the method in heavy nuclei.

  19. Isospin dependence of fragment spectra in heavy/super-heavy colliding nuclei at intermediate energies

    NASA Astrophysics Data System (ADS)

    Chugh, Rajiv; Kumar, Rohit; Vinayak, Karan Singh

    2016-05-01

    Using isospin-dependent quantum molecular dynamics (IQMD) approach, we performed a theoretical investigation of the evolution of various kinds of fragments in heavy and superheavy-ion reactions in the intermediate/medium energy domain. We demonstrated direct impact of symmetry energy and Coulomb interactions on the evolution of fragments. Final fragment spectra (yields) obtained from the analysis of various heavy/super-heavy ion reactions at different reaction conditions show high sensitivity towards Coulomb interactions and less significant sensitivity to symmetry energy forms. No inconsistent pattern of fragment structure is obtained in case of super-heavy ion involved reactions for all the parameterizations of density dependence of symmetry energy.

  20. Properties of high-energy isoscalar monopole excitations in medium-heavy mass spherical nuclei

    SciTech Connect

    Gorelik, M. L. Shlomo, Sh. Tulupov, B. A. Urin, M. H.

    2015-07-15

    The recently developed particle-hole dispersive optical model is applied to describe properties of high-energy isoscalar monopole excitations in medium-heavy mass spherical nuclei. In particular, the double transition density averaged over the energy of the isoscalar monopole excitations is considered for {sup 208}Pb in a wide energy interval, which includes the isoscalar giant monopole resonance and its overtone. The energy-averaged strength functions of these resonances are also analyzed.

  1. Composition and energy spectra of heavy nuclei of unknown origin detected on Skylab

    NASA Technical Reports Server (NTRS)

    Chan, J. H.; Price, P. B.

    1975-01-01

    At the orbit of Skylab, steeply falling energy spectra of nuclei with atomic numbers of at least 8 and energies between about 10 and 40 MeV/amu at intensities much higher than seen outside the magnetosphere were observed. The composition is consistent with that of the solar corona. It is suggested that heavy solar-wind ions enter the magnetosphere, are accelerated, and populate the inner radiation belt.

  2. {alpha}-decay calculations of heavy and superheavy nuclei using effective mean-field potentials

    SciTech Connect

    Pei, J. C.; Lin, Z. J.; Xu, F. R.; Zhao, E. G.

    2007-10-15

    Using an effective potential that is based on the Skyrme-Hartree-Fock mean-field model, systematic {alpha}-decay properties of even-even heavy and superheavy nuclei have been investigated. Calculations do not raise any adjustable parameter. The obtained {alpha}-decay half-lives agree reasonably well with experimental data. The characteristics of the effective potential and the deformation effect on the {alpha} decay are discussed.

  3. Production of heavy and superheavy neutron-rich nuclei in transfer reactions

    SciTech Connect

    Zagrebaev, V. I.; Greiner, Walter

    2011-04-15

    The problem of production and study of heavy neutron-rich nuclei has been intensively discussed during recent years. Many reasons arouse a great interest in this problem. The present limits of the upper part of the nuclear map are very close to the {beta} stability line while the unexplored area of heavy neutron-rich nuclides (also those located along the neutron closed shell N=126 to the right-hand side of the stability line) is extremely important for nuclear astrophysic investigations and, in particular, for the understanding of the r process of astrophysical nucleogenesis. For elements with Z>100 only neutron deficient isotopes (located to the left of the stability line) have been synthesized so far. The 'northeast' area of the nuclear map can be reached neither in fusion-fission reactions nor in fragmentation processes widely used nowadays for the production of new nuclei. Multinucleon transfer processes in near barrier collisions of heavy (and very heavy, U-like) ions seem to be the only reaction mechanism allowing us to produce and explore neutron-rich heavy nuclei including those located at the superheavy island of stability. In this paper several transfer reactions for different projectile-target combinations are studied in detail. Besides the predictions for the cross sections of such processes, we also analyze the angular and energy distributions of primary and survived reaction products in the laboratory frame. These results, as well as predicted excitation functions for the yields of neutron-rich superheavy isotopes, might be useful for the design of appropriate experimental equipment and for carrying out experiments of such kind.

  4. ENERGY SPECTRA OF COSMIC-RAY NUCLEI AT HIGH ENERGIES

    SciTech Connect

    Ahn, H. S.; Ganel, O.; Han, J. H.; Kim, K. C.; Lee, M. H.; Malinine, A.; Allison, P.; Beatty, J. J.; Brandt, T. J.; Bagliesi, M. G.; Bigongiari, G.; Maestro, P.; Marrocchesi, P. S.; Barbier, L.; Childers, J. T.; DuVernois, M. A.; Conklin, N. B.; Coutu, S.; Jeon, J. A.; Minnick, S.

    2009-12-10

    We present new measurements of the energy spectra of cosmic-ray (CR) nuclei from the second flight of the balloon-borne experiment Cosmic-Ray Energetics And Mass (CREAM). The instrument included different particle detectors to provide redundant charge identification and measure the energy of CRs up to several hundred TeV. The measured individual energy spectra of C, O, Ne, Mg, Si, and Fe are presented up to approx10{sup 14} eV. The spectral shape looks nearly the same for these primary elements and it can be fitted to an E {sup -2.66} {sup +}- {sup 0.04} power law in energy. Moreover, a new measurement of the absolute intensity of nitrogen in the 100-800 GeV/n energy range with smaller errors than previous observations, clearly indicates a hardening of the spectrum at high energy. The relative abundance of N/O at the top of the atmosphere is measured to be 0.080 +- 0.025 (stat.)+-0.025 (sys.) at approx800 GeV/n, in good agreement with a recent result from the first CREAM flight.

  5. Nucleosynthesis of neutron-rich heavy nuclei during explosive helium burning in a 15 solar-mass supernova

    NASA Technical Reports Server (NTRS)

    Blake, J. B.; Woosley, S. E.; Weaver, T. A.; Schramm, D. N.

    1980-01-01

    The production of heavy nuclei during explosive helium burning has been calculated using the Weaver and Woosley self-consistent model of a complete 15 solar-mass star and the n-process code of Blake and Schramm. It was found that the resulting neutron-rich heavy nuclei are not produced in the relative abundances of solar-system r-process material (such as a Pt peak) nor are any actinides produced. Basically insufficient neutrons are available.

  6. {gamma}-ray Spectroscopy of Proton Drip-Line Nuclei in the A{approx}130 Region using SPIRAL beams

    SciTech Connect

    Stezowski, O.; Guinet, D.; Lautesse, Ph.; Meyer, M.; Redon, N.; Rosse, B.; Schmitt, Ch.; De France, G.; Bhattachasyya, S.; Mukherjee, G.

    2008-11-11

    A fusion-evaporation experiment has been performed with a SPIRAL {sup 76}Kr radioactive beam in order to study the deformation of rare-earth nuclei near the proton drip-line. The experimental setup consisted in the EXOGAM {gamma}-array, coupled to the light-charged particles (LCP) DIAMANT detector and to the VAMOS heavy-ion spectrometer. The difficulties inherent to such measurements are enlightened. The coupling between EXOGAM and DIAMANT has been used to decrease the huge background caused by the radioactivity of the beam. It further permits assigning new {gamma}-ray transitions to specific residual nuclei. A {gamma}-ray belonging to the {sup 130}Pm level scheme has thus been observed for the first time.

  7. Study of near-stability nuclei populated as fission fragments in heavy-ion fusion reactions

    SciTech Connect

    Fotiadis, Nikolaos; Nelson, Ronald O; Devlin, Matthew; Cizewski, Jolie A; Krucken, Reiner; Clark, R M; Fallon, Paul; Lee, I Yang; Macchiavelli, Agusto O; Becker, John A; Younes, Walid

    2010-01-01

    Examples are presented to illustrate the power of prompt {gamma}-ray spectroscopy of fission fragments from compound nuclei with A {approx} 200 formed in fusion-evaporation reactions in experiments using the Gammasphere Ge-detector array. Complementary methods, such as Coulomb excitation and deep-inelastic processes, are also discussed. In other cases (n, xn{gamma}) reactions on stable isotopes have been used to establish neutron excitation functions for {gamma}-rays using a pulsed 'white'-neutron source, coupled to a high-energy-resolution germanium-detector array. The excitation functions can unambiguously assign {gamma}-rays to a specific reaction product. Results from all these methods bridge the gaps in the systematics of high-spin states between the neutron-deficient and neutron-rich nuclei. Results near shell closures should motivate new shell model calculations.

  8. Excitation energies of double isobar-analog states in heavy nuclei

    SciTech Connect

    Poplavskii, I. V.

    1988-12-01

    Several new relationships are established for isomultiplets on the basis of a theory in which the Coulomb coupling constant (CCC) is allowed to be complex. In particular, the following rule is formulated: the energies for fission or decay of members of an isomultiplet into a charged cluster and members of the corresponding daughter isomultiplet are equidistant. This relationship is well satisfied for isomultiplets with /ital A/less than or equal to60. By extrapolating the rule for fission and decay energies to the region of heavy nuclei, the excitation energies /ital E//sub /ital x// of double isobar-analog states (DIASs) are found for the nuclei /sup 197,199/Hg, /sup 205/Pb, /sup 205 - -209/Po, /sup 209/At, and /sup 238/Pu. A comparison of the computed energies /ital E//sub /ital x// with the experimentally measured values for /sup 208/Po attest to the reliability and good accuracy of the method proposed here when used to determine the excitation energies of DIASs in heavy nuclei.

  9. The project of the mass separator of atomic nuclei produced in heavy ion induced reactions

    NASA Astrophysics Data System (ADS)

    Oganessian, Yu. Ts.; Shchepunov, V. A.; Dmitriev, S. N.; Itkis, M. G.; Gulbekyan, G. G.; Khabarov, M. V.; Bekhterev, V. V.; Bogomolov, S. L.; Efremov, A. A.; Pashenko, S. V.; Stepantsov, S. V.; Yeremin, A. V.; Yavor, M. I.; Kalimov, A. G.

    2003-05-01

    A new separator and mass analyzer, named MASHA (mass analyzer of super heavy atoms), has been designed at the Flerov Laboratory JINR Dubna to separate and measure masses of nuclei and molecules with precision better than 10 -3. The set up can work in the wide mass range from A≈20 to A≈500, its mass acceptance is as large as ±2.8%. In particular, it allows unambiguous mass identification of super heavy nuclei with a resolution better than 1 amu at the level of 300 amu. Synthesized in nuclear reactions nuclides are emitted from an ECR ion source at energy E=40 kV and charge state Q=+1. Then they pass the following steps of separation and analysis: the first section of rough separation, the second section of separation and mass analysis and the final section of separation with a 90° electrostatic deflector. In the focal plane of the device, a focal plane detector determines positions (masses) of studied nuclei. Ion optics of the analyzer, optimized up to the second order, is considered. Description of its elements and subsystems is given.

  10. Formation of Heavy Compound Nuclei, Their Survival and Correlation with Longtime-Scale Fission

    SciTech Connect

    Karamian, S. A.; Yakushev, A.-B.

    2007-05-22

    Fusion of two massive nuclei with formation of super-heavy compound nucleus (CN) is driven by the potential energy gradient, as follows from the analysis of nuclear reaction cross-sections. The conservative energy of the system is deduced in simple approximation using regularized nuclear mass and interaction barrier values. Different reaction for the synthesis of Zc (110-118) nuclei are compared and the favourable conditions are found for fusion of the stable (W-Pt) isotopes with radioactive fission fragment projectiles, like 94Kr or 100Sr. Thus, the cold fusion method can be extended for a synthesis of elements with Z > 113. Survival of the evaporation residue is defined by the neutron-to-fission probability ratio and by the successful emission of gammas at final step of the reaction. Numerical estimates are presented. Fixation of evaporation residue products must correlate with longtime-scale fission and available experimental results are discussed.

  11. Application of JAERI quantum molecular dynamics model for collisions of heavy nuclei

    NASA Astrophysics Data System (ADS)

    Ogawa, Tatsuhiko; Hashimoto, Shintaro; Sato, Tatsuhiko; Niita, Koji

    2016-06-01

    The quantum molecular dynamics (QMD) model incorporated into the general-purpose radiation transport code PHITS was revised for accurate prediction of fragment yields in peripheral collisions. For more accurate simulation of peripheral collisions, stability of the nuclei at their ground state was improved and the algorithm to reject invalid events was modified. In-medium correction on nucleon-nucleon cross sections was also considered. To clarify the effect of this improvement on fragmentation of heavy nuclei, the new QMD model coupled with a statistical decay model was used to calculate fragment production cross sections of Ag and Au targets and compared with the data of earlier measurement. It is shown that the revised version can predict cross section more accurately.

  12. Delta excitations in heavy nuclei induced by (3He,t) and (p,n) reactions

    NASA Astrophysics Data System (ADS)

    Esbensen, H.; Lee, T.-S. H.

    1985-12-01

    Delta excitations in heavy nuclei, induced by charge exchange reactions, are studied using the surface response model. The residual pion-exchange interaction and the self-energy of the delta in a nuclear medium is included in the random-phase-approximation response. The peak position observed in (3He,t) reactions can be explained by the self-energy of the delta extracted from pion-nucleus scattering, and the magnitude of the cross section is consistent with Glauber theory. The comparison to (p,n) data is reasonable; contributions from neutron decay of the delta, which are left out in the calculations, constitute a substantial experimental background.

  13. Energy Approach to Resonance states of Compound Superheavy Nucleus and EPPP in Heavy Nuclei Collisions

    SciTech Connect

    Glushkov, Alexander V.

    2005-10-26

    A consistent unified energy approach (operator perturbation theory) is used for numerical calculations of the electron-positron pair production cross-section in heavy nuclei collisions. Resonance phenomena in the nuclear subsystem lead to the structurization of the positron spectrum produced. The positron spectrum narrow peaks are treated as resonance states of the compound superheavy nucleus. Calculation results for the differential cross-sections of the U-U collision energies E1 (E1=162.0keV- third s-resonance; E1=247.6keV- the fourth s-resonance) are presented.

  14. Analytical approach to cosmic ray ionization by nuclei with charge Z in the middle atmosphere - Distribution of galactic CR effects

    NASA Astrophysics Data System (ADS)

    Velinov, P. I. Y.; Mateev, L.

    2008-11-01

    The effects of galactic and solar cosmic rays (CR) in the middle atmosphere are considered in this work. A new analytical approach for CR ionization by protons and nuclei with charge Z in the lower ionosphere and middle atmosphere is developed in this paper. For this purpose the ionization losses (d E/d h) according to the Bohr-Bethe-Bloch formula for the energetic charged particles are approximated in three different energy intervals. More accurate expressions for energy decrease E( h) and electron production rate profiles q( h) are derived. The obtained formulas allow comparatively easy computer programming. The integrand in q( h) gives the possibility for application of adequate numerical methods - such as Romberg method or Gauss quadrature, for the solution of the mathematical problem. On this way the process of interaction of cosmic ray particles with the upper, middle and lower atmosphere will be described much more realistically. Computations for cosmic ray ionization in the middle atmosphere are made. The full CR composition is taken into account: protons, Helium ( α-particles), light L, medium M, heavy H and very heavy VH group of nuclei.

  15. Relativistic theory for the elementary process of bremsstrahlung induced by heavy spin-zero nuclei

    NASA Astrophysics Data System (ADS)

    Jakubassa-Amundsen, D. H.

    2016-05-01

    Doubly and triply differential cross sections for the bremsstrahlung emission by high-energy spin-polarized electrons in the field of heavy bare nuclei are calculated within a fully relativistic partial-wave approach at collision energies between 1 and 30 MeV. Investigating 208Pb as a test case, it is shown that if the photons are emitted at backward angles, nuclear size effects may play an important role even below 10 MeV. Comparison is made with experimental data on the circular polarization correlations between incoming electron and emitted photon at a collision energy of 3.5 MeV. It is demonstrated that, independent of energy, the plane-wave Born approximation severely underestimates the cross section for heavy targets. Moreover, it gives at most a qualitative prescription of the polarization correlations, except possibly in the forward hemisphere.

  16. Super-heavy nuclei with Z = 118 and their mass and charge spectrum of fission fragments

    NASA Astrophysics Data System (ADS)

    Maslyuk, V. T.; Smolyanyuk, A. V.

    2015-12-01

    The first results of the calculation of the mass and charge yields of fission fragments for over 60 isotopes which have Z = 118 are presented. The results were obtained from the condition of thermodynamic ordering of the ensemble of fission fragments. The role of neutrons shells with N = 82 or N = 126 and protons shells with Z = 50 in the realization of symmetric (or one-humped) and asymmetric (2- or 3-humped) shapes of the fission-fragment yields with the transition from neutron-proficient to neutron-deficient isotopes was investigated. The data of fragments yields had been analyzed under the conditions of a “cold” and “hot” fission. The calculations show the possibility to identify super-heavy nuclei with Z ≥ 118 produced synthetically by heavy-ion reaction on their mass/charge spectrum division.

  17. Cosmic gamma-rays and cosmic nuclei above 1 TeV

    NASA Technical Reports Server (NTRS)

    Watson, A. A.

    1986-01-01

    Work on cosmic gamma rays and cosmic nuclei above I TeV is described and evaluated. The prospect that gamma ray astronomy above I TeV will give new insights into high energy cosmic ray origin within our galaxy is particularly bright.

  18. Competition between {alpha} decay and spontaneous fission for heavy and superheavy nuclei

    SciTech Connect

    Xu Chang; Ren Zhongzhou; Guo Yanqing

    2008-10-15

    We systematically investigate the {alpha}-decay and spontaneous fission half-lives for heavy and superheavy nuclei with proton number Z{>=}90. The {alpha}-decay half-lives are obtained by the deformed version of the density-dependent cluster model (DDCM). In the DDCM, the microscopic potential between the {alpha} particle and the daughter nucleus is evaluated numerically from the double-folding model with the M3Y interaction. The influence of the core deformation on the double-folding potential is also properly taken into account by the multipole expansion method. The spontaneous fission half-lives of nuclei from {sup 232}Th to {sup 286}114 are calculated with the parabolic potential approximation by taking nuclear structure effects into account. The agreement between theoretical results and the newly observed data is satisfactory for both {alpha} emitters and spontaneous fission nuclei. The competition between {alpha} decay and spontaneous fission is analyzed in detail and the branching ratios of these two decay modes are predicted for the unknown cases.

  19. Studies of heavy-ion reactions and transuranic nuclei. Progress report, September 1, 1992--August 31, 1993

    SciTech Connect

    Schroeder, W.U.

    1993-08-01

    This report contain papers on the following topics: The Cold-Fusion Saga; Decay Patterns of Dysprosium Nuclei Produced in {sup 32}S + {sup 118,124}Sn Fusion Reactions; Unexpected Features of Reactions Between Very Heavy Ions at Intermediate Bombarding Energies; Correlations Between Neutrons and Charged Products from the Dissipative Reaction {sup 197}Au+{sup 208}Pb at E/A = 29 MeV; Dissipative Dynamics of Projectile-Like Fragment Production in the Reaction {sup 209}Bi+{sup 136}Xe at E/A = 28.2 MeV; Dynamical Production of Intermediate-Mass Fragments in Peripheral {sup 209}Bi+{sup 136}Xe Collisions at E{sub lab}/A = 28.2 MeV; The Rochester 960-Liter Neutron Multiplicity Meter; A Simple Pulse Processing Concept for a Low-Cost Pulse-Shape-Based Particle Identification; A One-Transistor Preamplifier for PMT Anode Signals; A Five-Channel Multistop TDC/Event Handler for the SuperBall Neutron Multiplicity Meter; Construction of the SuperBall -- a 16,000-Liter Neutron Detector for Calorimetric Studies of Intermediate-Energy Heavy-Ion Reactions; A Computer Code for Light Detection Efficiency Calculations for Photo-multipliers of a Neutron Detector; Evaluation of Gd-Loaded Liquid Scintillators for the SuperBall Neutron Calorimeter; and Measurement of the Interaction of Cosmic-Ray {mu}{sup {minus}} with a Muon Telescope.

  20. Extracting nuclear sizes of medium to heavy nuclei from total reaction cross sections

    NASA Astrophysics Data System (ADS)

    Horiuchi, W.; Hatakeyama, S.; Ebata, S.; Suzuki, Y.

    2016-04-01

    Background: Proton and neutron radii are fundamental quantities of atomic nuclei. To study the sizes of short-lived unstable nuclei, there is a need for an alternative to electron scattering. Purpose: The recent paper by Horiuchi et al. [Phys. Rev. C 89, 011601(R) (2014)], 10.1103/PhysRevC.89.011601 proposed a possible way of extracting the matter and neutron-skin thickness of light- to medium-mass nuclei using total reaction cross section, σR. The analysis is extended to medium to heavy nuclei up to lead isotopes with due attention to Coulomb breakup contributions as well as density distributions improved by paring correlation. Methods: We formulate a quantitative calculation of σR based on the Glauber model including the Coulomb breakup. To substantiate the treatment of the Coulomb breakup, we also evaluate the Coulomb breakup cross section due to the electric dipole field in a canonical-basis-time-dependent-Hartree-Fock-Bogoliubov theory in the three-dimensional coordinate space. Results: We analyze σR's of 103 nuclei with Z =20 , 28, 40, 50, 70, and 82 incident on light targets, H,21, 4He, and 12C. Three kinds of Skyrme interactions are tested to generate those wave functions. To discuss possible uncertainty due to the Coulomb breakup, we examine its dependence on the target, the incident energy, and the Skyrme interaction. The proton is a most promising target for extracting the nuclear sizes as the Coulomb excitation can safely be neglected. We find that the so-called reaction radius, aR=√{σR/π } , for the proton target is very well approximated by a linear function of two variables, the matter radius and the skin thickness, in which three constants depend only on the incident energy. We quantify the accuracy of σR measurements needed to extract the nuclear sizes. Conclusions: The proton is the best target because, once the incident energy is set, its aR is very accurately determined by only the matter radius and neutron-skin thickness. If σR's at

  1. Charge-exchange resonances and restoration of the Wigner SU(4)-symmetry in heavy and superheavy nuclei

    NASA Astrophysics Data System (ADS)

    Lutostansky, Yu. S.; Tikhonov, V. N.

    2016-01-01

    Energies of the giant Gamow-Teller and analog resonances -EG and EA, respectively, - are calculated within the microscopic theory of finite Fermi system. The calculated energy difference ΔEG-A = EG-EA tends to zero with A in heavy nuclei indicating the restoration of Wigner SU(4)-symmetry. The calculated ΔEG-A values are in good agreement with the experimental data. The average deviation is 0.30MeV for the 33 considered nuclei where experimental data are available. The ΔEG-A values are investigated for very heavy and superheavy nuclei up to the mass number A = 290. Using the experimental data for the analog resonance energies, the isotopic dependence of the Coulomb energy differences for neighboring isobars are analyzed within the SU(4)-approach for more than 400 nuclei in the mass number range of A = 3-244. The Wigner SU(4)-symmetry restoration for heavy and superheavy nuclei is confirmed. It is shown that the restoration of SU(4)-symmetry does not contradict the possibility of the existence of the "island of stability" in the region of superheavy nuclei.

  2. [C ii] emission from galactic nuclei in the presence of X-rays

    NASA Astrophysics Data System (ADS)

    Langer, W. D.; Pineda, J. L.

    2015-08-01

    Context. The luminosity of [C ii] is used as a probe of the star formation rate in galaxies, but the correlation breaks down in some active galactic nuclei (AGNs). Models of the [C ii] emission from galactic nuclei do not include the influence of X-rays on the carbon ionization balance, which may be a factor in reducing the [C ii] luminosity. Aims: We aim to determine the properties of the ionized carbon and its distribution among highly ionized states in the interstellar gas in galactic nuclei under the influence of X-ray sources. We calculate the [C ii] luminosity in galactic nuclei under the influence of bright sources of soft X-rays. Methods: We solve the balance equation of the ionization states of carbon as a function of X-ray flux, electron, atomic hydrogen, and molecular hydrogen density. These are input to models of [C ii] emission from the interstellar medium (ISM) in galactic nuclei representing conditions in the Galactic central molecular zone and a higher density AGN model. The behavior of the [C ii] luminosity is calculated as a function of the X-ray luminosity. We also solve the distribution of the ionization states of oxygen and nitrogen in highly ionized regions. Results: We find that the dense warm ionized medium (WIM) and dense photon dominated regions (PDRs) dominate the [C ii] emission when no X-rays are present. The X-rays in galactic nuclei can affect strongly the C+ abundance in the WIM, converting some fraction to C2+ and higher ionization states and thus reducing its [C ii] luminosity. For an X-ray luminosity L(X-ray) ≳ 1043 erg s-1 the [C ii] luminosity can be suppressed by a factor of a few, and for very strong sources, L(X-ray) >1044 erg s-1 such as found for many AGNs, the [C ii] luminosity is significantly depressed. Comparison of the model with several extragalactic sources shows that the [C ii] to far-infrared ratio declines for L(X-ray) ≳ 1043 erg s-1, in reasonable agreement with our model. Conclusions: We conclude that X-rays

  3. Development of the Experimental Setup Dedicated for Alpha, Gamma and Electron Spectroscopy of Heavy Nuclei at FLNR JINR

    SciTech Connect

    Yeremin, A.; Malyshev, O.; Popeko, A.; Lopez-Martens, A.; Hauschild, K.; Dorvaux, O.; Saro, S.; Pantelika, D.

    2010-04-30

    Various types of reactions and identification techniques were applied in the investigation of formation cross sections and decay properties of transuranium elements. The fusion--evaporation reactions with heavy targets, recoil--separation techniques and identification of nuclei by the parent--daughter generic coincidences with the known daughter-nuclei after implantation into position--sensitive detectors were the most successful tools for production and identification of the heaviest elements known presently. This technique may be further improved and presently it may be very promising for the identification of new elements, search for new isotopes and measurement of new decay data for the known nuclei.At the Flerov Laboratory of Nuclear Reactions (JINR, Dubna), investigations of the complete fusion reactions leading to the synthesis of heavy and superheavy nuclei with the use of heavy ion beams from a powerful U400 cyclotron have been an important part of the experimental program. It is planned to upgrade U400 cyclotron of the FLNR, to deliver beams with higher intensities and smooth variation of energies.New experimental set up, the velocity filter, is now developing for synthesis and studies of the decay properties of heavy nuclei. At the focal plane of the separator GABRIELA set up (alpha,beta,gamma detectors array) will be installed.

  4. Progress report on the ultra heavy cosmic ray experiment (AO178)

    NASA Technical Reports Server (NTRS)

    Thompson, A.; Osullivan, D.; Bosch, J.; Keegan, R.; Wenzel, K.-P.; Jansen, F.; Domingo, C.

    1993-01-01

    The Ultra Heavy Cosmic Ray Experiment (UHCRE) is based on a modular array of 192 side-viewing solid state nuclear track detector stacks. These stacks were mounted in sets of four in 48 pressure vessels employing sixteen peripheral Long Duration Exposure Facility (LDEF) trays. The extended duration of the LDEF mission has resulted in a greatly enhanced scientific yield from the UHCRE. The geometry factor for high energy cosmic ray nuclei, allowing for Earth shadowing, was 30 sq m-sr, giving a total exposure factor of 170 sq m-sr-y at an orbital inclination of 28.4 degrees. Scanning results indicate that about 3000 cosmic ray nuclei in the charge region with Z greater than 65 were collected. This sample is more than ten times the current world data in the field (taken to be the data set from the HEAO-3 mission plus that from the Ariel-6 mission) and is sufficient to provide the world's first statistically significant sample of actinide (Z greater than 88) cosmic rays. Results to date are presented including details of ultra-heavy cosmic ray nuclei, analysis of pre-flight and post-flight calibration events and details of track response in the context of detector temperature history. The integrated effect of all temperature and age related latent track variations cause a maximum charge shift of +/- 0.8 e for uranium and +/- 0.6 e for the platinum-lead group. The precision of charge assignment as a function of energy is derived and evidence for remarkably good charge resolution achieved in the UHCRE is considered. Astrophysical implications of the UHCRE charge spectrum are discussed.

  5. High energy neutrinos from astrophysical accelerators of cosmic ray nuclei

    NASA Astrophysics Data System (ADS)

    Anchordoqui, Luis A.; Hooper, Dan; Sarkar, Subir; Taylor, Andrew M.

    2008-02-01

    Ongoing experimental efforts to detect cosmic sources of high energy neutrinos are guided by the expectation that astrophysical accelerators of cosmic ray protons would also generate neutrinos through interactions with ambient matter and/or photons. However, there will be a reduction in the predicted neutrino flux if cosmic ray sources accelerate not only protons but also significant numbers of heavier nuclei, as is indicated by recent air shower data. We consider plausible extragalactic sources such as active galactic nuclei, gamma ray bursts and starburst galaxies and demand consistency with the observed cosmic ray composition and energy spectrum at Earth after allowing for propagation through intergalactic radiation fields. This allows us to calculate the expected neutrino fluxes from the sources, normalized to the observed cosmic ray spectrum. We find that the likely signals are still within reach of next generation neutrino telescopes such as IceCube.PACS95.85.Ry98.70.Rz98.54.Cm98.54.EpReferencesFor a review, see:F.HalzenD.HooperRep. Prog. Phys.6520021025A.AchterbergIceCube CollaborationPhys. Rev. Lett.972006221101A.AchterbergIceCube CollaborationAstropart. Phys.262006282arXiv:astro-ph/0611063arXiv:astro-ph/0702265V.NiessANTARES CollaborationAIP Conf. Proc.8672006217I.KravchenkoPhys. Rev. D732006082002S.W.BarwickANITA CollaborationPhys. Rev. Lett.962006171101V.Van ElewyckPierre Auger CollaborationAIP Conf. Proc.8092006187For a survey of possible sources and event rates in km3 detectors see e.g.,W.BednarekG.F.BurgioT.MontaruliNew Astron. Rev.4920051M.D.KistlerJ.F.BeacomPhys. Rev. D742006063007A. Kappes, J. Hinton, C. Stegmann, F.A. Aharonian, arXiv:astro-ph/0607286.A.LevinsonE.WaxmanPhys. Rev. Lett.872001171101C.DistefanoD.GuettaE.WaxmanA.LevinsonAstrophys. J.5752002378F.A.AharonianL.A.AnchordoquiD.KhangulyanT.MontaruliJ. Phys. Conf. Ser.392006408J.Alvarez-MunizF.HalzenAstrophys. J.5762002L33F.VissaniAstropart. Phys.262006310F.W

  6. Heavy nuclei far from stability in the N < 126, Z > 82 region

    SciTech Connect

    Back, B.B.; Blumenthal, D.J.; Carpenter, M.P.

    1995-08-01

    There are long-standing calculations suggesting that nuclei in the N < 126, Z > 82 region far from stability exhibit deformation effects. Away from stability an observable permanent quadrupole deformation should be achieved but, as yet, there is no experimental evidence for such an effect. A series of experiments was performed to assess the production of nuclei in this region and to study their structure. These experiments were performed using gamma-ray spectroscopy to investigate the low-lying level schemes and alpha-particle spectroscopy in order to isolate fine structure in the decay. The low-lying level structure of the neutron-deficient isotope {sup 202}Rn was studied, for the first time, using the {sup 181}Ta({sup 27}Al,6n) and {sup 192}Pt({sup 16}O,6n) reactions. Gamma-ray transitions between excited states in {sup 202}Rn were identified by mass tagging the Fragment Mass Analyzer and by observation of coincident X rays. Transitions in {sup 203}Rn were also identified. The level scheme deduced from these data is consistent with the systematics of light radon isotopes below the N = 126 shell closure and with theoretical calculations indicating that the ground-state shape should not be strongly deformed at N = 116.

  7. Development of High Resolution Solid-State Track Detector for Ultra Heavy Cosmic Ray Observation

    NASA Astrophysics Data System (ADS)

    Kodaira, S.; Doke, T.; Hareyama, M.; Hasebe, N.; Ota, S.; Sakurai, K.; Sato, M.; Yasuda, N.; Nakamura, S.; Kamei, T.; Tawara, H.; Ogura, K.

    The observation of trans-iron nuclei in galactic cosmic rays (Z?30) requires a high performance cosmic ray detector telescope with a very large exposure area because of their extremely low fluxes. It is realized by the use of solid-state track detector of CR-39, which has an advantage of easy extension of exposure area. The verification of mass and nuclear charge identifications with CR-39 solid-state track detector newly developed for the observation of heavy cosmic ray particles has been made using Fe ions from NIRS-HIMAC. Mass and charge resolutions for Fe nuclei are found to be ~0.22 amu and 0.22 cu in rms, respectively. Moreover, it is necessary to raise the Z/??detection threshold in order to suppress background tracks produced by galactic cosmic rays with Z/?<30. The new track detectors of copolymers of CR-39 and DAP (diallyl phthalate) have been developed and verified their performances. From the point of view of stability for the cosmic ray exposure environment such as temperature and vacuum in space, newly BP-1 glass detector with high sensitivity is also currently under development. The combination of such solid-state track detector with the high speed scanning system enables us to realize a large-scaled observation for trans-iron galactic cosmic rays.

  8. {gamma}-ray spectroscopy of the neutron-rich nuclei {sup 89}Rb, {sup 92}Y, and {sup 93}Y with multinucleon transfer reactions

    SciTech Connect

    Bucurescu, D.; Ionescu-Bujor, M.; Iordachescu, A.; Mihai, C.; Suliman, G.; Rusu, C.; Marginean, N.; Ur, C. A.; Marginean, R.; De Angelis, G.; Corradi, L.; Vedova, F. Della; Fioretto, E.; Gadea, A.; Guiot, B.; Napoli, D.; Stefanini, A. M.; Valiente-Dobon, J. J.; Bazzacco, D.; Beghini, S.

    2007-12-15

    The positive-parity yrast states in the {sup 89}Rb, {sup 92}Y, and {sup 93}Y nuclei were studied using {gamma}-ray spectroscopy with heavy-ion induced reactions. In the multinucleon transfer reactions {sup 208}Pb+{sup 90}Zr (590 MeV) and {sup 238}U+{sup 82}Se (505 MeV), several {gamma}-ray transitions were identified in these nuclei by means of coincidences between recoiling ions identified with the PRISMA spectrometer and {gamma} rays detected with the CLARA {gamma}-ray array in thin target experiments. Level schemes were subsequently determined from triple-{gamma} coincidences recorded with the GASP array in a thick target experiment, in the reactions produced by a 470 MeV {sup 82}Se beam with a {sup 192}Os target. The observed level schemes are compared to shell-model calculations.

  9. Cross section parameterizations for cosmic ray nuclei. 1: Single nucleon removal

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Townsend, Lawrence W.

    1992-01-01

    Parameterizations of single nucleon removal from electromagnetic and strong interactions of cosmic rays with nuclei are presented. These parameterizations are based upon the most accurate theoretical calculations available to date. They should be very suitable for use in cosmic ray propagation through interstellar space, the Earth's atmosphere, lunar samples, meteorites, spacecraft walls and lunar and martian habitats.

  10. Excitation of Δ and N* resonances in isobaric charge-exchange reactions of heavy nuclei

    NASA Astrophysics Data System (ADS)

    Vidaña, I.; Benlliure, J.; Geissel, H.; Lenske, H.; Scheidenberger, C.; Vargas, J.

    2016-01-01

    We present a model for the study of the excitation of Δ(1232) and N*(1440) resonances in isobaric charge-exchange (AZ, A(Z ± 1)) reactions of heavy nuclei. Quasi-elastic and inelastic elementary processes contributing to the double differential cross sections of the reactions are described in terms of the exchange of virtual pions. The inelastic channel includes processes where the resonances are excited both in the target and in the projectile nucleus. We present results for reactions of 112Sn and 124Sn on different targets. Our results confirm that the position of the Δ peak is insensitive to targets with mass number A ≥ 12, and show that the origin of the Δ peak shift towards low excitation energies, with respect to its position in reactions with a proton target, can be easily explained in terms of the superposition of the different excitation mechanisms contributing to the reaction.

  11. Finite amplitude method applied to the giant dipole resonance in heavy rare-earth nuclei

    NASA Astrophysics Data System (ADS)

    Oishi, Tomohiro; Kortelainen, Markus; Hinohara, Nobuo

    2016-03-01

    Background: The quasiparticle random phase approximation (QRPA), within the framework of nuclear density functional theory (DFT), has been a standard tool to access the collective excitations of atomic nuclei. Recently, the finite amplitude method (FAM) was developed in order to perform the QRPA calculations efficiently without any truncation on the two-quasiparticle model space. Purpose: We discuss the nuclear giant dipole resonance (GDR) in heavy rare-earth isotopes, for which the conventional matrix diagonalization of the QRPA is numerically demanding. A role of the Thomas-Reiche-Kuhn (TRK) sum rule enhancement factor, connected to the isovector effective mass, is also investigated. Methods: The electric dipole photoabsorption cross section was calculated within a parallelized FAM-QRPA scheme. We employed the Skyrme energy density functional self-consistently in the DFT calculation for the ground states and FAM-QRPA calculation for the excitations. Results: The mean GDR frequency and width are mostly reproduced with the FAM-QRPA, when compared to experimental data, although some deficiency is observed with isotopes heavier than erbium. A role of the TRK enhancement factor in actual GDR strength is clearly shown: its increment leads to a shift of the GDR strength to higher-energy region, without a significant change in the transition amplitudes. Conclusions: The newly developed FAM-QRPA scheme shows remarkable efficiency, which enables one to perform systematic analysis of GDR for heavy rare-earth nuclei. The theoretical deficiency of the photoabsorption cross section could not be improved by only adjusting the TRK enhancement factor, suggesting the necessity of an approach beyond self-consistent QRPA and/or a more systematic optimization of the energy density functional (EDF) parameters.

  12. Review of even element super-heavy nuclei and search for element 120

    NASA Astrophysics Data System (ADS)

    Hofmann, S.; Heinz, S.; Mann, R.; Maurer, J.; Münzenberg, G.; Antalic, S.; Barth, W.; Burkhard, H. G.; Dahl, L.; Eberhardt, K.; Grzywacz, R.; Hamilton, J. H.; Henderson, R. A.; Kenneally, J. M.; Kindler, B.; Kojouharov, I.; Lang, R.; Lommel, B.; Miernik, K.; Miller, D.; Moody, K. J.; Morita, K.; Nishio, K.; Popeko, A. G.; Roberto, J. B.; Runke, J.; Rykaczewski, K. P.; Saro, S.; Scheidenberger, C.; Schött, H. J.; Shaughnessy, D. A.; Stoyer, M. A.; Thörle-Pospiech, P.; Tinschert, K.; Trautmann, N.; Uusitalo, J.; Yeremin, A. V.

    2016-06-01

    The reaction 54Cr + 248Cm was investigated at the velocity filter SHIP at GSI, Darmstadt, with the intention to study production and decay properties of isotopes of element 120. Three correlated signals were measured, which occurred within a period of 279ms. The heights of the signals correspond with the expectations for a decay sequence starting with an isotope of element 120. However, a complete decay chain cannot be established, since a signal from the implantation of the evaporation residue cannot be identified unambiguously. Measured properties of the event chain are discussed in detail. The result is compared with theoretical predictions. Previously measured decay properties of even element super-heavy nuclei were compiled in order to find arguments for an assignment from the systematics of experimental data. In the course of this review, a few tentatively assigned data could be corrected. New interpretations are given for results which could not be assigned definitely in previous studies. The discussion revealed that the cross-section for production of element 120 could be high enough so that a successful experiment seems possible with presently available techniques. However, a continuation of the experiment at SHIP for a necessary confirmation of the results obtained in a relatively short irradiation of five weeks is not possible at GSI presently. Therefore, we decided to publish the results of the measurement and of the review as they exist now. In the summary and outlook section we also present concepts for the continuation of research in the field of super-heavy nuclei.

  13. The Energetic Trans-Iron Composition Experiment (ENTICE) on the Heavy Nuclei Explorer (HNX) Mission

    NASA Technical Reports Server (NTRS)

    Israel, M. H.; Adams, James H., Jr.; Barbier, L. M.; Binns, W. R.; Christian, E. R.; Craig, N.; Cummings, A. C.; Doke, T.; Hasebe, N.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    The ENTICE experiment is one of two instruments that make up the HNX mission. The experimental goal of ENTICE is to measure with high precision the elemental abundances of all nuclei with Z between 10 and 82. This will enable us to determine if the injection mechanism for the cosmic ray accelerator is controlled by FIP or Volatility and to study the mix of nucleosynthetic processes that contribute to the galactic cosmic ray source. The ENTICE experiment utilizes the dE/dx-C method of charge determination and consists of silicon dE/dx detectors, Cherenkov detectors with two different refractive indices, and a fiber hodoscope. We will describe the instrument and its performance based on beam tests of a prototype instrument.

  14. New aspects of heavy cosmic rays from calcium to nickel (Z = 20 to 28)

    NASA Technical Reports Server (NTRS)

    Mewaldt, Richard A.; Webber, W. R.

    1990-01-01

    Over the two year course of this grant a study was conducted to explore the implications of composition measurements of heavy cosmic rays made by the Third High Energy Astronomy Observatory (HEAO-3). To interpret these and other measurements this study combined for the first time new laboratory measurements of the fragmentation cross sections of heavy nuclei, a new semi-empirical cross section formula, and the latest in cosmic ray propagation and solar modulation models. These models were used to interpret abundance measurements from six recent satellite experiments, including, in particular, two from HEAO-3. The principal results of the study were: (1) an improved interpretation of the Mn-54 clock in cosmic rays, including predictions of the isotopic abundances of Mn for comparison with future isotope measurements; (2) the first realization of the effect of Mn-54 decay on studies of the source abundances of Fe isotopes; (3) improved source abundances of the elements Ar, Ca, Cr, Mn, Fe, and Ni in the cosmic ray source material; (4) an improved fit to the abundances of Fe secondaries in cosmic rays; and (5) additional evidence that supports the validity of the leaky-box model of cosmic ray propagation in the galaxy. This final report summarizes these new results, the new tools that were developed to obtain them, and presents a bibliography of talks and publications that resulted from this work.

  15. Contribution of cosmic ray heavy ions to the radiation hazard in manned space flights.

    PubMed

    Domingo, C; Font, J; Baixeras, C; Font, L l; Fernandez, F

    1999-01-01

    Primary cosmic radiation arriving near the Earth may be classified into two general categories: the gamma component and the hadronic component. The hadronic component contains mainly protons, a small amount of alpha particles and a smaller amount of heavier charged nuclei (ions). Although the fluxes of these heavier ions are very small in comparison to those of protons, they are able to originate a huge linear energy transfer (LET). This work studies the contribution of heavy ions from cosmic rays to the radiation hazard to which the crew of a manned long duration space flight might be exposed. The geometry of the energy deposition by a heavy ion is studied, and it is found that energies of the order of up to 10(23) J kg-1 are deposited. PMID:11542231

  16. Energy Spectra of Cosmic Ray Nuclei to Above 100 Gev/nucleon. [measurement of energy spectra of cosmic ray nuclei boron to iron

    NASA Technical Reports Server (NTRS)

    Simon, M.; Spiegelhauer, H.; Schmidt, W. K. H.; Siohan, F.; Ormes, J. F.; Balasubrahmanyan, V. K.; Arens, J. F.

    1979-01-01

    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.

  17. Electron-positron pairs in physics and astrophysics: From heavy nuclei to black holes

    NASA Astrophysics Data System (ADS)

    Ruffini, Remo; Vereshchagin, Gregory; Xue, She-Sheng

    2010-02-01

    Due to the interaction of physics and astrophysics we are witnessing in these years a splendid synthesis of theoretical, experimental and observational results originating from three fundamental physical processes. They were originally proposed by Dirac, by Breit and Wheeler and by Sauter, Heisenberg, Euler and Schwinger. For almost seventy years they have all three been followed by a continued effort of experimental verification on Earth-based experiments. The Dirac process, e+e-→2γ, has been by far the most successful. It has obtained extremely accurate experimental verification and has led as well to an enormous number of new physics in possibly one of the most fruitful experimental avenues by introduction of storage rings in Frascati and followed by the largest accelerators worldwide: DESY, SLAC etc. The Breit-Wheeler process, 2γ→e+e-, although conceptually simple, being the inverse process of the Dirac one, has been by far one of the most difficult to be verified experimentally. Only recently, through the technology based on free electron X-ray laser and its numerous applications in Earth-based experiments, some first indications of its possible verification have been reached. The vacuum polarization process in strong electromagnetic field, pioneered by Sauter, Heisenberg, Euler and Schwinger, introduced the concept of critical electric field Ec=me2c3/(eħ). It has been searched without success for more than forty years by heavy-ion collisions in many of the leading particle accelerators worldwide. The novel situation today is that these same processes can be studied on a much more grandiose scale during the gravitational collapse leading to the formation of a black hole being observed in Gamma Ray Bursts (GRBs). This report is dedicated to the scientific race. The theoretical and experimental work developed in Earth-based laboratories is confronted with the theoretical interpretation of space-based observations of phenomena originating on cosmological

  18. The UH-nuclei cosmic ray detector on the third High Energy Astronomy Observatory

    NASA Technical Reports Server (NTRS)

    Binns, W. R.; Israel, M. H.; Klarmann, J.; Scarlett, W. R.; Waddington, C. J.; Stone, E. C.

    1981-01-01

    The third High Energy Astronomy Observatory satellite (HEAO-3) carries a particle telescope for the detection of highly charged cosmic ray nuclei. These nuclei, which have Z equal to or greater than 28, are much rarer than the lower charged nuclei in the cosmic radiation. As a consequence, this particle telescope was required to have a large collecting area as well as an ability to resolve individual elements. This paper describes the telescope, composed of large area parallel plate ionization chambers, multiwire ion chamber hodoscopes and a Cherenkov radiation detector. The resulting telescope has a total geometry factor of 59,000 sq cm sr and is capable of measuring the charges of nuclei in the range Z = 14-120.

  19. Description of electromagnetic and favored α transitions in heavy odd-mass nuclei

    NASA Astrophysics Data System (ADS)

    Dumitrescu, A.; Delion, D. S.

    2016-02-01

    We describe electromagnetic and favored α transitions to rotational bands in odd-mass nuclei built upon a single particle state with angular momentum projection Ω ≠1/2 in the region 88 ≤Z ≤98 . We use the particle coupled to an even-even core approach described by the coherent state model and the coupled channels method to estimate partial α -decay widths. We reproduce the energy levels of the rotational band where favored α transitions occur for 26 nuclei and predict B (" close=")E 2 )">E 2 values for electromagnetic transitions to the band head using a deformation parameter and a Hamiltonian strength parameter for each nucleus, together with an effective collective charge depending linearly on the deformation parameter. Where experimental data are available, the contribution of the single particle effective charge to the total B value is calculated. The Hamiltonian describing the α -nucleus interaction contains two terms, a spherically symmetric potential given by the double-folding of the M3Y nucleon-nucleon interaction plus a repulsive core simulating the Pauli principle and a quadrupole-quadrupole (QQ) interaction. The α -decaying state is identified as a narrow outgoing resonance in this potential. The intensity of the transition to the first excited state is reproduced by the QQ coupling strength. It depends linearly both on the nuclear deformation and the square of the reduced width for the decay to the band head, respectively. Predicted intensities for transitions to higher excited states are in a reasonable agreement with experimental data. This formalism offers a unified description of energy levels, electromagnetic and favored α transitions for known heavy odd-mass α emitters.

  20. L X-ray emission induced by heavy ions

    NASA Astrophysics Data System (ADS)

    Pajek, M.; Banaś, D.; Braziewicz, J.; Majewska, U.; Semaniak, J.; Fijał-Kirejczyk, I.; Jaskóła, M.; Czarnacki, W.; Korman, A.; Kretschmer, W.; Mukoyama, T.; Trautmann, D.

    2015-11-01

    Particle-induced X-ray emission (PIXE) technique is usually applied using typically 1 MeV to 3 MeV protons or helium ions, for which the ion-atom interaction is dominated by the single ionization process. For heavier ions the multiple ionization plays an increasingly important role and this process can influence substantially both the X-ray spectra and atomic decay rates. Additionally, the subshell coupling effects are important for the L- and M-shells ionized by heavy ions. Here we discuss the main features of the X-ray emission induced by heavy ions which are important for PIXE applications, namely, the effects of X-ray line shifts and broadening, vacancy rearrangement and change of the fluorescence and Coster-Kronig yields in multiple ionized atoms. These effects are illustrated here by the results of the measurements of L X-ray emission from heavy atoms bombarded by 6 MeV to 36 MeV Si ions, which were reported earlier. The strong L-subshell coupling effects are observed, in particular L2-subshell, which can be accounted for within the coupling subshell model (CSM) developed within the semiclassical approximation. Finally, the prospects to use heavy ions in PIXE analysis are discussed.

  1. Heavy Cosmic Ray Measurement Aboard Spacelab-1

    NASA Technical Reports Server (NTRS)

    Beaujean, R.; Krause, J.; Fischer, E.; Enge, W.

    1985-01-01

    A stack of CR-39 plastic track detectors was exposed to cosmic radiation during the 10 days mission aboard Spacelab-1. A part of the stack was rotated one revolution within 7 days. The impact time of most of the particles was correlated with the orbit position of the shuttle and thus with geomagnetic field parameters. The analysis of heavy particles with charge Z greater than or equal to 6 in the energy range 50-150 MeV per nucleon with special emphasis on geomagnetically forbidden particles is reported.

  2. Fragmentation of spherical radioactive heavy nuclei as a novel probe of transient effects in fission

    SciTech Connect

    Schmitt, C.; Schmidt, K.-H.; Kelic, A.; Heinz, A.; Jurado, B.

    2010-06-15

    Peripheral collisions with radioactive heavy-ion beams at relativistic energies are discussed as an innovative approach for probing the transient regime experienced by fissile systems evolving toward quasiequilibrium and thereby studying the viscous nature of nuclear matter. A dedicated experiment using the advanced technical installations of GSI, Darmstadt, made it possible to realize ideal conditions for the investigation of relaxation effects in a metastable well. Combined with a highly sensitive experimental signature, it provides a measure of the transient effects with respect to the flux over the fission barrier. Within a two-step reaction process, 45 proton-rich unstable spherical isotopes between At and Th produced by projectile-fragmentation of a stable {sup 238}U beam have been used as secondary projectiles which impinge on lead target nuclei. The fragmentation of the radioactive projectiles results in nearly spherical compound nuclei that span a wide range in excitation energy and fissility. The decay of these excited systems by fission is studied with a dedicated setup which, together with the inverse kinematics of the reaction, permits the detection of both fission products in coincidence and the determination of their atomic numbers with high resolution. The information on the nuclear charges of the two fragments is used to sort the data according to the initial excitation energy and fissility of the compound nucleus. The width of the fission-fragment nuclear charge distribution is shown to be specifically sensitive to presaddle transient effects and is used to establish a clock for the passage of the saddle point. The comparison of the experimental results with model calculations points to a fission delay tau{sub trans} of (3.3+-0.7)x10{sup -21} s for initially spherical compound nuclei, independent of excitation energy and fissility. This value suggests a nuclear dissipation strength beta at small deformation of (4.5+-0.5)x10{sup 21} s{sup -1}. The

  3. Density functional theory computation of Nuclear Magnetic Resonance parameters in light and heavy nuclei

    NASA Astrophysics Data System (ADS)

    Sutter, Kiplangat

    This thesis illustrates the utilization of Density functional theory (DFT) in calculations of gas and solution phase Nuclear Magnetic Resonance (NMR) properties of light and heavy nuclei. Computing NMR properties is still a challenge and there are many unknown factors that are still being explored. For instance, influence of hydrogen-bonding; thermal motion; vibration; rotation and solvent effects. In one of the theoretical studies of 195Pt NMR chemical shift in cisplatin and its derivatives illustrated in Chapter 2 and 3 of this thesis. The importance of representing explicit solvent molecules explicitly around the Pt center in cisplatin complexes was outlined. In the same complexes, solvent effect contributed about half of the J(Pt-N) coupling constant. Indicating the significance of considering the surrounding solvent molecules in elucidating the NMR measurements of cisplatin binding to DNA. In chapter 4, we explore the Spin-Orbit (SO) effects on the 29Si and 13C chemical shifts induced by surrounding metal and ligands. The unusual Ni, Pd, Pt trends in SO effects to the 29Si in metallasilatrane complexes X-Si-(mu-mt)4-M-Y was interpreted based on electronic and relativistic effects rather than by structural differences between the complexes. In addition, we develop a non-linear model for predicting NMR SO effects in a series of organics bonded to heavy nuclei halides. In chapter 5, we extend the idea of "Chemist's orbitals" LMO analysis to the quantum chemical proton NMR computation of systems with internal resonance-assisted hydrogen bonds. Consequently, we explicitly link the relationship between the NMR parameters related to H-bonded systems and intuitive picture of a chemical bond from quantum calculations. The analysis shows how NMR signatures characteristic of H-bond can be explained by local bonding and electron delocalization concepts. One shortcoming of some of the anti-cancer agents like cisplatin is that they are toxic and researchers are looking for

  4. Nuclear fragmentation parameters needed for interpretation of observed fluxes of UH cosmic ray nuclei

    NASA Technical Reports Server (NTRS)

    Waddington, C. J.; Binns, W. R.; Cummings, J. R.; Garrard, T. L.; Geer, L. Y.; Klarmann, J.; Nilsen, B. S.

    1995-01-01

    Any study of the origin of the UH nuclei in the cosmic rays requires that their observed abundances be propagated back to the source. This demands a knowledge of the interaction cross sections in the materials of the detectors, any local overlying matter, and the interstellar medium. New measurements of interaction probabilities of 10.6 GeV/n gold nuclei show significant differences from previous measurements made at less than 1.0 GeV/n nuclei. These differences are particularly marked for a hydrogen target. Hence, those cross sections previously measured at low energies should not be applied to cosmic ray observations made at energies greater than or = 2 GeV/n. Without a measurement of the energy dependence of these cross sections it will be difficult to make reliable propagation calculations, since the differences between measured and predicted cross sections are still at the 20 to 30% level.

  5. The elemental and isotopic composition of galactic cosmic ray nuclei

    NASA Technical Reports Server (NTRS)

    Mewaldt, R. A.

    1983-01-01

    A directly accessible sample of matter which originates outside the solar system is provided by galactic cosmic rays. The present investigation is primarily concerned with progress related to questions raised regarding the similarity or difference between solar system matter and matter coming from outside the solar system. The investigation takes into account U.S. contributions to this topic over the period from 1979 to 1982. The cosmic ray (CR) abundances of all the elements from H to Ni (atomic number Z=1 to 28) have now been measured. Cosmic ray source (CRS) and solar system (SS) elemental compositions are listed in a table, and the ratio of CRS to SS abundance for 21 elements is shown in a graph. There is now clear evidence from CR isotope studies that the nucleosynthesis of CRS material has differed from that of SS material.

  6. Ultra-heavy cosmic rays: Theoretical implications of recent observations

    NASA Technical Reports Server (NTRS)

    Blake, J. B.; Hainebach, K. L.; Schramm, D. N.; Anglin, J. D.

    1977-01-01

    Extreme ultraheavy cosmic ray observations (Z greater or equal 70) are compared with r-process models. A detailed cosmic ray propagation calculation is used to transform the calculated source distributions to those observed at the earth. The r-process production abundances are calculated using different mass formulae and beta-rate formulae; an empirical estimate based on the observed solar system abundances is used also. There is the continued strong indication of an r-process dominance in the extreme ultra-heavy cosmic rays. However it is shown that the observed high actinide/Pt ratio in the cosmic rays cannot be fit with the same r-process calculation which also fits the solar system material. This result suggests that the cosmic rays probably undergo some preferential acceleration in addition to the apparent general enrichment in heavy (r-process) material. As estimate also is made of the expected relative abundance of superheavy elements in the cosmic rays if the anomalous heavy xenon in carbonaceous chondrites is due to a fissioning superheavy element.

  7. Early results from the ultra heavy cosmic ray experiment

    NASA Technical Reports Server (NTRS)

    Osullivan, D.; Thompson, A.; Bosch, J.; Keegan, R.; Wenzel, K.-P.; Jansen, F.; Domingo, C.

    1995-01-01

    Data extraction and analysis of the LDEF Ultra Heavy Cosmic Ray Experiment is continuing. Almost twice the pre LDEF world sample has been investigated and some details of the charge spectrum in the region from Z approximately 70 up to and including the actinides are presented. The early results indicate r process enhancement over solar system source abundances.

  8. Pygmy dipole resonance as a constraint on the neutron skin of heavy nuclei

    SciTech Connect

    Piekarewicz, J.

    2006-04-15

    The isotopic dependence of the isovector Pygmy dipole response in tin is studied within the framework of the relativistic random-phase approximation. Regarded as an oscillation of the neutron skin against the isospin-symmetric core, the pygmy dipole resonance may place important constraints on the neutron skin of heavy nuclei and, as a result, on the equation of state of neutron-rich matter. The present study centers around two questions. First, is there a strong correlation between the development of a neutron skin and the emergence of low-energy isovector dipole strength? Second, could one use the recently measured Pygmy dipole resonance in {sup 130}Sn and {sup 132}Sn to discriminate among theoretical models? For the first question we found that although a strong correlation between the neutron skin and the Pygmy dipole resonance exists, a mild anticorrelation develops beyond {sup 120}Sn. The answer to the second question suggests that models with overly large neutron skins--and thus stiff symmetry energies--are in conflict with experiment.

  9. Density slope of the nuclear symmetry energy from the neutron skin thickness of heavy nuclei

    SciTech Connect

    Chen Liewen; Ko Che Ming; Xu Jun; Li Baoan

    2010-08-15

    Expressing explicitly the parameters of the standard Skyrme interaction in terms of the macroscopic properties of asymmetric nuclear matter, we show in the Skyrme-Hartree-Fock approach that unambiguous correlations exist between observables of finite nuclei and nuclear matter properties. We find that existing data on neutron skin thickness {Delta}r{sub np} of Sn isotopes give an important constraint on the symmetry energy E{sub sym}({rho}{sub 0}) and its density slope L at saturation density {rho}{sub 0}. Combining these constraints with those from recent analyses of isospin diffusion and the double neutron/proton ratio in heavy-ion collisions at intermediate energies leads to a more stringent limit on L approximately independent of E{sub sym}({rho}{sub 0}). The implication of these new constraints on the {Delta}r{sub np} of {sup 208}Pb as well as the core-crust transition density and pressure in neutron stars is discussed.

  10. Outflowing X-ray corona in Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Wang, Junxian; Liu, Teng; Yang, Huan; Zhu, Feifan; Zhou, Youyuan

    2015-08-01

    Hard X-ray emission in radio-quiet AGNs is believed to be produced via inverse Compton scattering by hot and compact corona near the super massive black hole. However the origin and physical properties of the coronae, including geometry, kinematics and dynamics, yet remain poorly known. Taking [OIV] 25.89um emission line as an isotropic indicator of AGN's intrinsic luminosity, we compare the intrinsic corona X-ray emission between Seyfert 1 and Compton-thin Seyfert 2 galaxies, which are viewed at different inclinations according to the unification scheme. We find that Seyfert 1 galaxies are brighter in "absorption-corrected" 2-10 keV emission by a factor of ~2.8, comparing with Compton-thin Seyfert 2 galaxies. The Seyfert 1 and Compton-thin Seyfert 2 galaxies follow a statistically identical correlation between the absorption-corrected 2-10 keV luminosity and the SWIFT BAT 14-195 keV luminosity, indicating that our absorption correction to the 2-10 keV flux is sufficient. The difference between the two populations thus can not be attributed to X-ray absorption, and instead implies an intrinsic anisotropy in the corona X-ray emission. This striking anisotropy of X-ray emission can be explained by a bipolar outflowing corona with a bulk velocity of ~0.3-0.5c. This would provide a natural link between the so-called coronae and weak jets in these systems. We also show that how this study would affect our understanding to the nature of mid-infrared emission in AGNs and the properties of dusty torus. Furthermore, such anisotropy implies that, contrary to previous understanding based on the assumption of isotropic corona emission, hard X-ray AGN surveys are biased against type 2 AGNs even after absorption-correction, and careful correction for this effect is required to measure the obscured fraction from X-ray surveys. Other interesting consequences of this discovery will also be discussed.

  11. OCCUPATION OF X-RAY-SELECTED GALAXY GROUPS BY X-RAY ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Allevato, V.; Finoguenov, A.; Hasinger, G.; Cappelluti, N.; Miyaji, T.; Salvato, M.; Brusa, M.; Zamorani, G.; Gilli, R.; George, M. R.; Tanaka, M.; Silverman, J.; Civano, F.; Elvis, M.; Shankar, F.

    2012-10-10

    We present the first direct measurement of the mean halo occupation distribution (HOD) of X-ray-selected active galactic nuclei (AGNs) in the COSMOS field at z {<=} 1, based on the association of 41 XMM and 17 C-COSMOS AGNs with member galaxies of 189 X-ray-detected galaxy groups from XMM-Newton and Chandra data. We model the mean AGN occupation in the halo mass range log M{sub 200} [M{sub Sun }] = 13-14.5 with a rolling-off power law with the best-fit index {alpha} = 0.06(- 0.22; 0.36) and normalization parameter f{sub a} 0.05(0.04; 0.06). We find the mean HOD of AGNs among central galaxies to be modeled by a softened step function at log M{sub h} > log M{sub min} = 12.75(12.10, 12.95) M{sub Sun} while for the satellite AGN HOD we find a preference for an increasing AGN fraction with M{sub h} , suggesting that the average number of AGNs in satellite galaxies grows slower ({alpha}{sub s} < 0.6) than the linear proportion ({alpha}{sub s} = 1) observed for the satellite HOD of samples of galaxies. We present an estimate of the projected autocorrelation function (ACF) of galaxy groups over the range of r{sub p} = 0.1-40 h {sup -1} Mpc at (z) = 0.5. We use the large-scale clustering signal to verify the agreement between the group bias estimated by using the observed galaxy groups ACF and the value derived from the group mass estimates. We perform a measurement of the projected AGN-galaxy-group cross-correlation function, excluding from the analysis AGNs that are within galaxy groups and we model the two-halo term of the clustering signal with the mean AGN HOD based on our results.

  12. Increased delivery of condensation nuclei during the Late Heavy Bombardment to the terrestrial and martian atmospheres

    NASA Astrophysics Data System (ADS)

    Losiak, Anna

    2014-05-01

    During the period of the Late Heavy Bombardment (LHB), between 4.1 and 3.8 Ga, the impact rate within the entire Solar System was up to a few thousand times higher than the current value (Ryder 2002, Bottke et al. 2012, Fassett and Minton 2013). Multiple basin-forming events on inner planets that occurred during this time had a strong but short-lasting (up to few thousands of years) effect on atmospheres of Earth and Mars (Sleep et al. 1989, Segura et al. 2002, 2012). However, the role of the continuous flux of smaller impactors has not been assessed so far. We calculated the amount of meteoric material in the 10^-3 kg to 106 kg size range delivered to Earth and Mars during the LHB based on the impact flux at the top of the Earth's atmosphere based on results from Bland and Artemieva (2006). Those values were recalculated for Mars based on Ivanov and Hartmann (2009) and then recalculated to the LHB peak based on estimates from Ryder (2002), Bottke et al. (2012), Fassett and Minton (2013). During the LHB, the amount of meteoritic material within this size range delivered to Earth was up to ~1.7*10^10 kg/year and 1.4*10^10 kg/year for Mars. The impactors that ablate and are disrupted during atmospheric entry can serve as cloud condensation nuclei (Rosen 1968, Hunten et al. 1980, Ogurtsov and Raspopov 2011). The amount of material delivered during LHB to the upper stratosphere and lower mezosphere (Hunten et al. 1980, Bland and Artemieva 2006) is comparable to the current terrestrial annual emission of mineral cloud condensation nuclei of 0.5-8*10^12 kg/year (Tegen 2003). On Mars, the availability of condensation nuclei is one of the main factors guiding water-ice cloud formation (Montmessin et al. 2004), which is in turn one of the main climatic factors influencing the hydrological cycle (Michaels et al. 2006) and radiative balance of the planet (Haberle et al. 1999, Wordsworth et al. 2013, Urata and Toon 2013). Increased delivery of condensation nuclei during the

  13. A new transition radiation detector for cosmic ray nuclei

    NASA Technical Reports Server (NTRS)

    Lheureux, J.; Meyer, P.; Muller, D.; Swordy, S.

    1981-01-01

    Test measurements on materials for transition radiation detectors at a low Lorentz factor are reported. The materials will be based on board Spacelab-2 for determining the composition and energy spectra of nuclear cosmic rays in the 1 TeV/nucleon range. The transition radiation detectors consist of a sandwich of radiator-photon detector combinations. The radiators emit X-rays and are composed of polyolefin fibers used with Xe filled multiwired proportional chamber (MWPC) detectors capable of detecting particle Lorentz factors of several hundred. The sizing of the detectors is outlined, noting the requirement of a thickness which provides a maximum ratio of transition radiation to total signal in the chambers. The fiber radiator-MWPC responses were tested at Fermilab and in an electron cyclotron. An increase in transition radiation detection was found as a square power law of Z, and the use of six radiator-MWPC on board the Spacelab-2 is outlined.

  14. Setup with Laser Ionization in Gas Cell for Production and Study of Neutron-Rich Heavy Nuclei

    NASA Astrophysics Data System (ADS)

    Zagrebaev, V. I.; Zemlyanoy, S. G.; Kozulin, E. M.; Kudryavtsev, Yu.; Fedosseev, V.; Bark, R.; Janas, Z.; Othman, H. A.

    2015-11-01

    The present limits of the upper part of the nuclear map are very close to stability while the unexplored area of heavy neutron-rich nuclides along the neutron closed shell N=126 is extremely important for nuclear astrophysics investigations and, in particular, for the understanding of the r-process of astrophysical nucleosynthesis. This area of the nuclear map can be reached neither in fusion-fission reactions nor in fragmentation processes widely used nowadays for the production of exotic nuclei. A new way was recently proposed for the production of these nuclei via low-energy multi-nucleon transfer reactions. The estimated yields of neutron-rich nuclei are found to be significantly high in such reactions and several tens of new nuclides can be produced, for example, in the near-barrier collision of 136Xe with 208Pb. A new setup is proposed to produce and study heavy neutron-rich nuclei located along the neutron closed shell N=126.

  15. Ultrahigh energy cosmic ray nuclei from extragalactic pulsars and the effect of their Galactic counterparts

    NASA Astrophysics Data System (ADS)

    Fang, Ke; Kotera, Kumiko; Olinto, Angela V.

    2013-03-01

    The acceleration of ultrahigh energy nuclei in fast spinning newborn pulsars can explain the observed spectrum of ultrahigh energy cosmic rays and the trend towards heavier nuclei for energies above 1019 eV as reported by the Auger Observatory. Pulsar acceleration implies a hard injection spectrum ( ~ E-1) due to pulsar spin down and a maximum energy Emax ~ Z 1019 eV due to the limit on the spin rate of neutron stars. We have previously shown that the escape through the young supernova remnant softens the spectrum, decreases slightly the maximum energy, and generates secondary nuclei. Here we show that the distribution of pulsar birth periods and the effect of propagation in the interstellar and intergalactic media modifies the combined spectrum of all pulsars. By assuming a normal distribution of pulsar birth periods centered at 300 ms, we show that the contribution of extragalactic pulsar births to the ultrahigh energy cosmic ray spectrum naturally gives rise to a contribution to very high energy cosmic rays (VHECRs, between 1016 and 1018 eV) by Galactic pulsar births. The required injected composition to fit the observed spectrum depends on the absolute energy scale, which is uncertain, differing between Auger Observatory and Telescope Array. The contribution of Galactic pulsar births can also bridge the gap between predictions for cosmic ray acceleration in supernova remnants and the observed spectrum just below the ankle, depending on the composition of the cosmic rays that escape the supernova remnant and the diffusion behavior of VHECRs in the Galaxy.

  16. Heavy quarks and nuclei, or the charm & beauty of nuclear physics

    SciTech Connect

    Kharzeev, D.

    1997-09-22

    This report contains viewgraphs on the following: why heavy quarks? Heavy quarkonium in QCD vacuum and in matter; Phenomenology of quarkonium production; Induced decay of QCD vacuum in heavy ion collisions? Implications for quarkonium production; and Outlook.

  17. Gamma-ray spectroscopy of neutron-rich products of heavy-ion collisions

    SciTech Connect

    Carpenter, M.P.; Janssens, R.V.F.; Ahmad, I.

    1995-08-01

    Thick-target {gamma}{gamma} coincidence techniques are being used to explore the spectroscopy of otherwise hard-to-reach neutron-rich products of deep-inelastic heavy ion reactions. Extensive {gamma}{gamma} coincidence measurements were performed at ATLAS using pulsed beams of {sup 80}Se, {sup 136}Xe, and {sup 238}U on lead-backed {sup 122,124}Sn targets with energies 10-15% above the Coulomb barrier. Gamma-ray coincidence intensities were used to map out yield distributions with A and Z for even-even product nuclei around the target and around the projectile. The main features of the yield patterns are understandable in terms of N/Z equilibration. We had the most success in studying the decays of yrast isomers. Thus far, more than thirty new {mu}s isomers in the Z = 50 region were found and characterized. Making isotopic assignments for previously unknown {gamma}-ray cascades proves to be one of the biggest problems. Our assignments were based (a) on rare overlaps with radioactivity data, (b) on the relative yields with different beams, and (c) on observed cross-coincidences between {gamma} rays from light and heavy reaction partners. However, the primary products of deep inelastic collisions often are sufficiently excited for subsequent neutron evaporation, so {gamma}{gamma} cross-coincidence results require careful interpretation.

  18. The cosmological evolution and luminosity function of X-ray selected active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Maccacaro, T.; Gioia, I. M.; Avni, Y.; Giommi, P.; Griffiths, R. E.; Liebert, J.; Stocke, J.; Danziger, J.

    1983-01-01

    The cosmological evolution and the X-ray luminosity function of X-ray selected active galactic nuclei (AGNs) are derived and discussed. The sample used consists of 31 AGNs extracted from a fully identified sample of X-ray sources from the Einstein Observatory Medium Sensitivity Survey and is therefore exclusively defined by its X-ray properties. The distribution in space is found to be strongly nonuniform. The amount of cosmological evolution required by the X-ray data is derived in the framework of pure luminosity evolution and is found to be smaller than the amount determined from optically selected samples. The X-ray luminosity function is derived. It can be satisfactorily represented by a single power law only over a limited range of absolute luminosities. Evidence that the luminosity function flattens at low luminosity or steepens at high luminosity, or both, is presented and discussed.

  19. A Study of Heavy Trans-Iron Primary Cosmic Rays (Z More than or Equal to 55) with a Fast Film Cerenkov Detector. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Pinsky, L. S.

    1972-01-01

    The detection and measurement of the cosmic ray charge spectrum for nuclei heavier than iron (Fe, Z = 26) are discussed. These trans-iron nuclei are of great interest for several reasons. They promise to be one of the more sensitive clocks for use in determining the age of cosmic rays. The discovery of radioactive nuclides and their decay products in the primary flux, will allow an estimation of the elapsed time since these cosmic rays were synthesized. In addition, the relatively short interaction length of the very heavy trans-iron particles makes their relative abundance a source of information regarding the amount of interstellar matter that they had to traverse to reach the earth. A study of the trans-iron cosmic rays may provide clues as to the very processes of nucleosyntheses by which the bulk of the trans-iron nuclei in the universe are produced. This in turn may shed light on the mechanics of the supernova, which is postulated to be the major source of all cosmic rays. Finally, trans-iron cosmic ray experiments may demonstrate the existence of the recently postulated super-heavy nuclei.

  20. Challenging Cosmic Ray Propagation with Antiprotons: Evidence for a "Fresh" Nuclei Component?

    NASA Technical Reports Server (NTRS)

    Moskalenko, Igor V.; Strong, Andrew W.; Mashnik, Stepan G.; Ormes, Jonathan F.

    2002-01-01

    Recent measurements of the cosmic ray (CR) antiproton flux have been shown to challenge existing CR propagation models. It was shown that the reacceleration models designed to match secondary to primary nuclei ratio (e.g., Boron/Carbon) produce too few antiprotons, while the traditional non-reacceleration models can reproduce the antiproton flux but fall short of explaining the low-energy decrease in the secondary to primary nuclei ratio. Matching both the secondary to primary nuclei ratio and antiproton flux requires artificial breaks in the diffusion coefficient and the primary injection spectrum suggesting the need for other approaches. In the present paper we discuss one possibility to overcome these difficulties. Using the measured antiproton flux to fix the diffusion coefficient, we show that the spectra of primary nuclei as measured in the heliosphere may contain a fresh local unprocessed component at low energies, thus decreasing the measured secondary to primary nuclei ratio. A model reproducing antiprotons, B/C ratio, and abundances up to Ni is presented.

  1. Space plasma physics: isotopic stack: measurement of heavy cosmic rays.

    PubMed

    Beaujean, R; Schmidt, M; Enge, W; Siegmon, G; Krause, J; Fischer, E

    1984-07-13

    A stack of plastic nuclear track detectors was exposed to heavy cosmic rays on the pallet of Spacelab 1. Some layers of the stack were rotated with respect to the main stack to determine the arrival time of the particles. After return of the stack the latent particle tracks are revealed by chemical etching. Under the optical microscope the charge, mass, energy, and impact direction of the particles can be deduced from the track geometry. PMID:17837938

  2. May heavy neutrinos solve underground and cosmic-ray puzzles?

    SciTech Connect

    Belotsky, K. M. Fargion, D. Khlopov, M. Yu. Konoplich, R. V.

    2008-01-15

    Primordial heavy neutrinos of the fourth generation might explain different astrophysical puzzles. The simplest fourth-neutrino scenario is consistent with known fourth-neutrino physics, cosmic ray antimatter, cosmic gamma fluxes, and positive signals in underground detectors for a very narrow neutrino mass window (46-47 GeV). However, accounting for the constraint of underground experiment CDMS prohibits solution of cosmic-ray puzzles in this scenario. We have analyzed extended heavy-neutrino models related to the clumpiness of neutrino density, new interactions in heavy-neutrino annihilation, neutrino asymmetry, and neutrino decay. We found that, in these models, the cosmic-ray imprint may fit the positive underground signals in DAMA/Nal experiment in the entire mass range 46-70 GeV allowed from uncertainties of electroweak parameters, while satisfaction of the CDMS constraint reduces the mass range to around 50 GeV, where all data can come to consent in the framework of the considered hypothesis.

  3. Interaction of ultraviolet and X-ray radiation with gamma rays produced by a jet in active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Zbyszewska, Magda

    1994-01-01

    Recent observations by the Compton Gamma-Ray Observatory give evidence for the existence of a type of blazar with strong gamma-ray emission. Data obtained by EGRET for the quasar 3C 279 show a spectrum between 100 MeV and 10 GeV. Photons of such energies should interact with the X-rays and produce positron/electron pairs. If the optical depth against pair production for the gamma rays is large (tau(gamma gamma) greater than 1), the gamma-ray spectrum should be affected. The importance of this process has been pointed out by, e.g., Maraschi, Ghisellini, & Celotti (1992). Several works (e.g., Dermer 1993; Zbyszewska 1993; Sikora, Begelman, & Rees 1993) concerning gamma-ray radiation from quasar 3C 279 have proposed a model in which the gamma rays are produced via interaction between a moving cloud of relativistic electrons and external soft photons. The presence of gamma rays in active galactic nuclei spectra gives constraints on the localization and the luminosity of the medium which produces ultraviolet/X-ray photons. We investigate what conditions should be fulfilled in the above model to avoid the absorption of the gamma rays due to pair production.

  4. A comment on the validity of fragmentation parameters measured in nuclear emulsions. [cosmic ray nuclei

    NASA Technical Reports Server (NTRS)

    Waddington, C. J.

    1978-01-01

    Evidence is reexamined which has been cited as suggesting serious errors in the use of fragmentation parameters appropriate to an airlike medium deduced from measurements made in nuclear emulsions to evaluate corrections for certain effects in balloon-borne observations of cosmic-ray nuclei. Fragmentation parameters for hydrogenlike interactions are calculated and shown to be in overall good agreement with those obtained previously for air. Experimentally measured fragmentation parameters in emulsion are compared with values computed semiempirically, and reasonable agreement is indicated.

  5. Abundances of secondary elements among the ultra heavy cosmic rays: Results from HEAO-3

    NASA Technical Reports Server (NTRS)

    Klarmann, J.; Stone, E. C.; Binns, W. R.; Israel, M. H.; Margolis, S. H.; Waddington, C. J.; Garrard, T. L.; Kertzman, M. P.

    1985-01-01

    Observations of the abundances of elements of charge 62 or Z or = 73 in the cosmic radiation from the HEAO-3 Heavy Nuclei Experiment (HNE) are discussed. These elements, having solar, and presumably source, abundances much less than the heavier Pt and Pb groups, are expected to be largely products of spallation. Thus they are indicators of the conditions prevailing during the propagation of cosmic rays. The abundances have changed from those reported previously due to a different data selection. This results in better charge resolution and in a higher mean energy for the particles. All the particles included were required to have had a cutoff rigidity R sub c 5 GV. This allowed the charge determination to be based solely on the Cherenkov measurement.

  6. INSTRUMENTS AND METHODS OF INVESTIGATION Charge spectrum of galactic cosmic ray nuclei as measured in meteorite olivines

    NASA Astrophysics Data System (ADS)

    Aleksandrov, Andrei B.; Bagulya, Aleksandr V.; Vladimirov, Mikhail S.; Goncharova, Lyudmila A.; Ivliev, Aleksandr I.; Kalinina, Galina V.; Kashkarov, Leonid L.; Konovalova, Nina S.; Okat'eva, Natal'ya M.; Polukhina, Natal'ya G.; Rusetskii, Aleksei S.; Starkov, Nikolai I.

    2010-11-01

    This paper presents experimental results on galactic cosmic ray nuclei in olivine crystals from the Marjalahti and Eagle Station pallasites. The charge spectrum of the nuclei is measured to be in good agreement with the experimental data from the HEAO-3 and ARIEL-6 satellite missions.

  7. A new measurement of the flux of the light cosmic-ray nuclei at high energies

    NASA Technical Reports Server (NTRS)

    Buckley, J.; Dwyer, J.; Mueller, D.; Swordy, S.; Tang, K. K.

    1994-01-01

    A new cosmic-ray detector utilizing a ring-imaging Cerenkov counter to determine the energy of light cosmic-ray nuclei was flown on high-altitude balloon from Fort Sumner, NM, in 1991 September. We describe the design and performance of this instrument and discuss the data analysis procedures. The measurement provides a new determination of the absolute flux and differential energy spectrum of the primary cosmic-ray species helium between 40 and 320 GeV/nucleon. The experiment also yields the spectra of carbon and oxygen and some information on the intensities of the secondary nuclei Li, Be, and B. A comparison between our results and previous measurements of heavier nuclei (Z greater than or equal to 4) from HEAO 3 and Spacelab 2 indicates good consistency between these measurements. The data set is compared with the results of a leaky box propagation model. We find good agreement with this model if the abundance of helium relative to oxygen at the source is taken to be 25 +/- 6 and if the source spectrum is given by a power law in energy proportional to E(exp -2.15).

  8. Testing astrophysical models for the PAMELA positron excess with cosmic ray nuclei.

    PubMed

    Mertsch, Philipp; Sarkar, Subir

    2009-08-21

    The excess in the positron fraction measured by PAMELA has been interpreted as due to annihilation or decay of dark matter in the Galaxy. More prosaically it has been ascribed to direct production of positrons by nearby pulsars or due to pion production during diffusive shock acceleration of hadronic cosmic rays in nearby sources. We point out that measurements of secondary cosmic ray nuclei can discriminate between these possibilities. New data on the titanium-to-iron ratio support the hadronic source model above and enable a prediction for the boron-to-carbon ratio at energies above 100 GeV. PMID:19792709

  9. On the origin of power-law X-ray spectra of active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Schlosman, I.; Shaham, J.; Shaviv, G.

    1984-01-01

    In the present analytical model for a power law X-ray continuum production in active galactic nuclei, the dissipation of turbulent energy flux above the accretion disk forms an optically thin transition layer with an inverted temperature gradient. The emitted thermal radiation has a power law spectrum in the 0.1-100 keV range, with a photon energy spectral index gamma of about 0.4-1.0. Thermal X-ray contribution from the layer is 5-10 percent of the total disk luminosity. The gamma value of 0.75 is suggested as a 'natural' power law index for Seyfert galaxies and QSOs.

  10. Comparative study of depth dose distributions for beams of light and heavy nuclei in tissue-like media

    NASA Astrophysics Data System (ADS)

    Pshenichnov, Igor; Mishustin, Igor; Greiner, Walter

    2008-04-01

    We study the energy deposition by beams of light and heavy nuclei in tissue-like media for their possible application in charged-particle cancer therapy. The depth-dose distributions for protons, 3He, 12C, 20Ne and 58Ni nuclei are calculated within a Monte Carlo model based on the GEANT4 toolkit. These distributions are compared with each other and with available experimental data. It is demonstrated that nuclear fragmentation reactions essentially reduce the peak-to-plateau ratio of the dose profiles for deeply penetrating energetic ions heavier than 3He. On the other hand, the shapes of depth-dose profiles for all projectiles up to 58Ni were found similar at low penetration depths.

  11. Light (anti-)nuclei production and flow in relativistic heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Zhu, Lilin; Ko, Che Ming; Yin, Xuejiao

    2015-12-01

    Using the coalescence model based on the phase-space distributions of protons, neutrons, Λ s , and their antiparticles from a multiphase transport (AMPT) model, we study the production of light nuclei (H, H, He, H) and their antinuclei in Pb+Pb collisions at √{sN N}=2.76 TeV. The resulting transverse momentum spectra, elliptic flows, and coalescence parameters for these nuclei are presented and compared with available experimental data. We also show the constituent number scaled elliptic flows of these nuclei and discuss its implications.

  12. Preliminary spectra of the primary cosmic ray nuclei from the first year of the NUCLEON experiment exposure time

    NASA Astrophysics Data System (ADS)

    Panov, Alexander

    2016-07-01

    The NUCLEON cosmic ray observatory is designed to measure high energy cosmic ray composition and energy distribution. Methods of identification of charge and energy measurement for primary cosmic ray nuclei are considered. C, O, Ne, Mg, Si, Fe energy spectra are presented and discussed. The results are obtained from the first year of the planned exposure time.

  13. X-ray spectroscopy of AGN with the AXAF 'Microcalorimeter'. [Active Galactic Nuclei

    NASA Technical Reports Server (NTRS)

    Holt, Stephen S.

    1987-01-01

    A novel technique for X-ray spectroscopy has been configured as part of the definition payload of the AXAF Observatory. It is basically a calorimeter which, operating at 0.1 K, senses the total conversion of single photoelectrically absorbed X-rays via the differential temperature rise of the absorber. The technique promises to achieve less than 10 eV FWHM with near-unit efficiency simultaneously over the entire AXAF bandpass. This combination of high resolution and high efficiency allows for the possibility of investigating thermal, fluorescent and absorption X-ray line features in many types of X-ray source, including a large sample of active galactic nuclei.

  14. Ultrahigh energy cosmic ray nuclei from extragalactic pulsars and the effect of their Galactic counterparts

    SciTech Connect

    Fang, Ke; Olinto, Angela V.; Kotera, Kumiko E-mail: kotera@iap.fr

    2013-03-01

    The acceleration of ultrahigh energy nuclei in fast spinning newborn pulsars can explain the observed spectrum of ultrahigh energy cosmic rays and the trend towards heavier nuclei for energies above 10{sup 19} eV as reported by the Auger Observatory. Pulsar acceleration implies a hard injection spectrum ( ∼ E{sup −1}) due to pulsar spin down and a maximum energy E{sub max} ∼ Z 10{sup 19} eV due to the limit on the spin rate of neutron stars. We have previously shown that the escape through the young supernova remnant softens the spectrum, decreases slightly the maximum energy, and generates secondary nuclei. Here we show that the distribution of pulsar birth periods and the effect of propagation in the interstellar and intergalactic media modifies the combined spectrum of all pulsars. By assuming a normal distribution of pulsar birth periods centered at 300 ms, we show that the contribution of extragalactic pulsar births to the ultrahigh energy cosmic ray spectrum naturally gives rise to a contribution to very high energy cosmic rays (VHECRs, between 10{sup 16} and 10{sup 18} eV) by Galactic pulsar births. The required injected composition to fit the observed spectrum depends on the absolute energy scale, which is uncertain, differing between Auger Observatory and Telescope Array. The contribution of Galactic pulsar births can also bridge the gap between predictions for cosmic ray acceleration in supernova remnants and the observed spectrum just below the ankle, depending on the composition of the cosmic rays that escape the supernova remnant and the diffusion behavior of VHECRs in the Galaxy.

  15. Portable X-Ray, K-Edge Heavy Metal Detector

    SciTech Connect

    Fricke, V.

    1999-10-25

    The X-Ray, K-Edge Heavy Metal Detection System was designed and built by Ames Laboratory and the Center for Nondestructive Evaluation at Iowa State University. The system uses a C-frame inspection head with an X-ray tube mounted on one side of the frame and an imaging unit and a high purity germanium detector on the other side. the inspection head is portable and can be easily positioned around ventilation ducts and pipes up to 36 inches in diameter. Wide angle and narrow beam X-ray shots are used to identify the type of holdup material and the amount of the contaminant. Precise assay data can be obtained within minutes of the interrogation. A profile of the containerized holdup material and a permanent record of the measurement are immediately available.

  16. Isotopic dependence of the cross section for the induced fission of heavy nuclei

    SciTech Connect

    Bolgova, O. N.; Adamian, G. G.; Antonenko, N. V.; Zubov, A. S.; Ivanova, S. P.; Scheid, W.

    2009-06-15

    The cross sections for the induced fission of {sup 211-223}Ra, {sup 203-211}Rn, and {sup 221-231}Th nuclei undergoing peripheral collisions with {sup 208}Pb nuclei are calculated on the basis of the statistical model. The role of the N = 126 neutron shell is studied. The level density in excited nuclei is determined within the Fermi gas model and a model that takes into account the collective enhancement of the level density. The inclusion of a particle-hole excitation in addition to a collective Coulomb excitation makes it possible to obtain a satisfactory description of experimental cross sections for the fission of radium isotopes. The calculated ratios of the cross sections for the induced fission of {sup 236}U ({sup 237}U) and {sup 238}U ({sup 239}U) nuclei agree with experimental data.

  17. On the excitation energy of deep-hole states in medium-heavy-mass spherical nuclei

    NASA Astrophysics Data System (ADS)

    Kolomiytsev, G. V.; Igashov, S. Yu.; Urin, M. H.

    2016-01-01

    Within the particle-hole dispersive optical model it is shown that the spreading effect determines a significant part of the anomalously large excitation energy of deep-hole states in the 90Zr and 208Pb parent nuclei.

  18. Enrichment of heavy nuclei in He-3-rich flares. [Imp-7 observed solar events

    NASA Technical Reports Server (NTRS)

    Hurford, G. J.; Mewaldt, R. A.; Stone, E. C.; Vogt, R. E.

    1975-01-01

    IMP-7 observations of five solar-flare particle events characterized by He-3 enrichment are reported which show that such events are also enriched in nuclei with charges (Z) of at least 6. The ratio of these nuclei to H-1 at approximately 3 MeV/nucleon was found to be enriched by about 10 to 100 times, while the ratio with respect to He-4 was enriched by about 3 to 30 times. It is suggested that the simultaneous enhancement of He-3 and the heavier nuclei as well as the absence of H-2 and H-3 during the observed events may be partly due to a preferential acceleration process which depends on the ratio of the square of the charge to the atomic weight of the nuclei.

  19. Mean-field studies of time reversal breaking states in super-heavy nuclei with the Gogny force

    SciTech Connect

    Robledo, L. M.

    2015-10-15

    Recent progress on the description of time reversal breaking (odd mass and multi-quasiparticle excitation) states in super-heavy nuclei within a mean field framework and using several flavors of the Gogny interaction is reported. The study includes ground and excited states in selected odd mass isotopes of nobelium and mendelevium as well as high K isomeric states in {sup 254}No. These are two and four-quasiparticle excitations that are treated in the same self-consistent HFB plus blocking framework as the odd mass states.

  20. Properties and synthesis of heavy nuclei and properties of neutron star matter

    NASA Technical Reports Server (NTRS)

    Buchler, J. R.

    1974-01-01

    The nuclear Thomas-Fermi model which is based on nuclear matter calculations has been successfully applied to the study of the bulk properties of nuclei. It is ideally suited for extrapolation into the region of very neutron-rich and of superheavy nuclei. It is therefore a valuable approach for r-process calculations as well as for the study of neutron star matter at subnuclear densities.

  1. Determination of radiative neutron capture cross sections for unstable nuclei by the {gamma}-ray strength function method

    SciTech Connect

    Utsunomiya, H.; Goriely, S.

    2012-11-12

    An indirect method referred to as the {gamma}-ray strength function method has been devised to determine radiative neutron capture cross sections for unstable nuclei along the valley of {beta}-stability. This method is based on the {gamma}-ray strength function which interconnects radiative neutron capture and photoneutron emission within the statistical model. The method was applied to several unstable nuclei such as {sup 93,95}Zr, {sup 107}Pd, and 121,123Sn. This method offers a versatile application extended to unstable nuclei far from the stability when combined with Coulomb dissociation experiments at RIKEN-RIBF and GSI.

  2. New active galactic nuclei among the INTEGRAL and SWIFT X-ray sources

    NASA Astrophysics Data System (ADS)

    Burenin, R. A.; Mescheryakov, A. V.; Revnivtsev, M. G.; Sazonov, S. Yu.; Bikmaev, I. F.; Pavlinsky, M. N.; Sunyaev, R. A.

    2008-06-01

    We present the results of our optical identifications of a set of X-ray sources from the INTEGRAL and SWIFT all-sky surveys. The optical data have been obtained with the 1.5-m Russian-Turkish Telescope (RTT-150). Nine X-ray sources have been identified with active galactic nuclei (AGNs). Two of them are located in the nearby spiral galaxies MCG-01-05-047 and NGC 973 seen almost edge-on. One source, IGR J16562-3301, is probably a BL Lac object (blazar). The remaining AGNs are observed as the starlike nuclei of spiral galaxies whose spectra exhibit broad emission lines. The relation between the hard X-ray (17-60 keV) luminosity and the [O III] 5007 line luminosity, log L x/ L [O III] ≈ 2.1, holds good for most of the AGNs detected in hard X rays. However, the luminosities of some AGNs deviate from this relation. The fraction of such objects can reach ˜20%. In particular, the [O III] line flux is lower for two nearby edge-on spiral galaxies. This can be explained by the effect of absorption in the galactic disks.

  3. Analysis of nearly simultaneous x-ray and optical observations of active galactic nuclei

    SciTech Connect

    Webb, J.R.

    1988-01-01

    Rosemary Hill optical and EINSTEIN X-ray observations of a sample of 36 galactic nuclei (AGN) were reduced and analyzed. Seventy-two x-ray observations of these sources were reduced, nineteen of which yielded spectral information. Of these spectra observations, significant hydrogen column densities above the galactic value were required for nine of the active galactic nuclei. X-ray variability was detected in eight of the eleven sources which were observed more than once by EINSTEIN. Correlations between the x-ray and optical luminosities were investigated using the Jefferys method of least squares. This method allows for errors in both variables. The results indicate a strong correlation between the x-ray and optical luminosities for the entire sample. Division of the sample into groups with similar optical variability characteristics show that the less violently violent variable AGN are more highly correlated than the violently variable blazars. Infrared and radio observations were combined with the x-ray and optical observations of six AGN. These sources were modelled in terms of the synchrotron-self-Compton model. The turnover frequency falls between the infrared and radio data and reliable estimates of this parameter are difficult to estimate. Therefore the results were found as a function of the turnover frequency. Four sources required relativistic bulk motion or beaming. Multifrequency spectra made at different times for one individual source, 0235+164, required different amounts of beaming to satisfy the x-ray observations. Sizes of the emitting regions for the sources modelled ranged from 0.5 parsec to 1.0 parsec.

  4. THE EFFECTS OF X-RAY FEEDBACK FROM ACTIVE GALACTIC NUCLEI ON HOST GALAXY EVOLUTION

    SciTech Connect

    Hambrick, D. Clay; Ostriker, Jeremiah P.; Naab, Thorsten; Johansson, Peter H.

    2011-09-01

    Hydrodynamic simulations of galaxies with active galactic nuclei (AGNs) have typically employed feedback that is purely local, i.e., an injection of energy to the immediate neighborhood of the black hole (BH). We perform GADGET-2 simulations of massive elliptical galaxies with an additional feedback component: an observationally calibrated X-ray radiation field which emanates from the BH and heats gas out to large radii from the galaxy center. We find that including the heating and radiation pressure associated with this X-ray flux in our simulations enhances the effects which are commonly reported from AGN feedback. This new feedback model is twice as effective as traditional feedback at suppressing star formation, produces three times less star formation in the last 6 Gyr, and modestly lowers the final BH mass (30%). It is also significantly more effective than an X-ray background in reducing the number of satellite galaxies.

  5. Measurement of Relative Abundances of Ultra-Heavy Cosmic Rays with CALET on the ISS

    NASA Astrophysics Data System (ADS)

    Rauch, Brian; Calet Collaboration

    2016-03-01

    The CALorimetric Electron Telescope (CALET) is a Japanese-Italian-US astroparticle observatory that was launched from the Tanegashima Space Center on the H-IIB Launch Vehicle No.5 (H-IIB F5) aboard the KOUNOTORI5 (HTV5 cargo transfer vehicle) to the International Space Station (ISS) on August 19, 2015. The HTV5 arrived at the ISS on August 24, and CALET was installed on port 9 of the Japanese Experiment Module ``Kibo'' Exposed Facility (JEM-EF), where CALET underwent the planned turn on and checkout procedures. CALET has completed its commissioning phase and its main calorimeter (CAL) is observing the highest energy cosmic electrons from 1 GeV to 20 TeV, along with cosmic ray nuclei through iron up to 1,000 TeV and gamma-rays above 10 GeV. In a five-year mission CALET will also have the exposure to measure the relative abundances of the ultra-heavy (UH) cosmic rays with ~4 × the statistics of the TIGER instrument for the full CAL acceptance. Rigidity cutoffs based on the earth's geomagnetic field in the 51.6° inclination ISS orbit can provide an energy independent UH measurement with expanded acceptance with ~10 × the TIGER statistics. An overview of the anticipated performance and preliminary CALET UH analysis data will be presented. This research was supported by NASA at Washington University under Grant Number NNX11AE02G.

  6. Improved version of a binding energy formula for heavy and superheavy nuclei with Z{>=}90 and N{>=}140

    SciTech Connect

    Dong Tiekuang; Ren Zhongzhou

    2008-06-15

    A local formula of binding energy for heavy and superheavy nuclei has very recently been proposed [Dong and Ren, Phys. Rev. C 72, 064331 (2005)]. In this paper, the limit of the predictive ability of this local formula is investigated. It is found that the neutron-proton correlations should be considered when higher precision is required. On the one hand, we introduce a new term |N-Z-50|/A, and on the other hand we consider the different strengths of proton-proton, neutron-neutron, and neutron-proton pairing correlations. For the first time, the standard deviation {radical}({sigma}{sup 2}) of the binding energies for 117 nuclei with Z{>=}90 and N{>=}140 is reduced to 0.105 MeV. The {alpha} decay energies Q{sub {alpha}} and half-lives T{sub {alpha}} of nuclei with Z=102-118 are reproduced quite well. The proton drip line of superheavy elements from Md (Z=101) to Ds (Z=110) are predicted.

  7. Extending studies of the fusion of heavy nuclei to the neutron rich region using accelerated radioactive ion beams.

    SciTech Connect

    Shapira, Dan

    2011-01-01

    One of the stated goals for proposed and existing facilities that produce and accelerate radioactive ion beams is to explore and achieve a new understanding of the reactions mechanisms leading to the synthesis of the heaviest nuclei. Nuclear synthesis of two large nuclei into a single entity is a complex multistep process. The beam intensities of radioactive ions accelerated at present day facilities are not sufficient to synthesize super heavy elements. However the study of the iso-spin dependence of nuclear synthesis and the many processes competing with it can be carried out at present day facilities. Of special interest are cases where the interacting nuclei and the synthesized product are extremely neutron-rich. The effects of neutron excess on the reaction processes leading to the formation of the synthesized nucleus that emerged in earlier studies are poorly understood and sometimes counter intuitive. Results from measurements performed at HRIBF, as well as our plans for future measurements and the equipment being prepared will be presented.

  8. Spectral evolution of active galactic nuclei: A unified description of the X-ray and gamma-ray backgrounds

    SciTech Connect

    Letter, D.; Boldt, E.

    1982-09-01

    A model for spectral evolution is presented whereby active galactic nuclei (AGN) of the type observed individually have emerged from an earlier stage at zroughly-equal4 in which they are the thermal X-ray sources responsible for most of the comic X-ray background (CXB). We pursue the conjecture that these precursor objects are initially supermassive Schwarzschild black holes with accretion disks radiating near the Eddington luminosity limit. It is noted that after approx.10/sup 8/ years these central black holes are spun up to a ''canonical'' Kerr equilibriuim state (a/M = 0.998) and shown how they can lead to spectral evolution involving nonthermal emission extending to gamma-rays, at the expense of reduced thermal disk radiation. A superposition of sources in the precursor stage can thereby account for that major portion of the CXB remaining after the contributions of usual AGN are considered, while a superposition of AGN sources at z<1 can account for the gamima-ray background. Extensive X-ray measurements carried out with the HEAO 1 and HEAO 2 missions, as well as gamma-ray and optical data, are shown to compare favorably with principal features of this model. Several further observational tests are suggested for establishing the validity of this scenario for AGN spectral evolution.

  9. Isotopic dependence of fusion cross sections in reactions with heavy nuclei

    NASA Astrophysics Data System (ADS)

    Adamian, G. G.; Antonenko, N. V.; Scheid, W.

    2000-09-01

    The dependence of fusion cross section on the isotopic composition of colliding nuclei is analysed within the dinuclear system concept for compound nucleus formation. Probabilities of fusion and surviving probabilities, ingredients of the evaporation residue cross sections, depend decisively on the neutron numbers of the dinuclear system. Evaporation residue cross sections for the production of actinides and superheavy nuclei, listed in table form, are discussed and compared with existing experimental data. In the Pb-based reactions neutron-rich radioactive projectiles are shown to lead to similar fusion cross sections as stable projectiles.

  10. Tracks of heavy and superheavy cosmic nuclei in olivines of extraterrestrial origin

    NASA Astrophysics Data System (ADS)

    Ignatova, R.; Lkhagvasuren, D.; Otgonsuren, O.; Pellas, P.; Pereligin, V.; Pero, K.; Stetsenko, S.; Taneva, T.; Iadav, D.

    The results of a study of the tracks of galactic nulei with X equal to or greater than 50 are reviewed with particular reference to an analysis of meteoritic olivine samples using an annealing technique. More than 500 tracks of nuclei with Z equal to or greater than 50 have been detected, including three tracks that are 1.5-1.8 times longer than those of uranium and thorium. These tracks are thought to belong to nuclei with Z of not less than 110.