摘要:

Needs for better nuclear data for biomedical applications are chiefly of two kinds: decay-scheme and production data for radionuclides used in nuclear medicine, and cross sections and spectral information for high-LET radiations used in radiation therapy of cancer, especially high-energy neutrons. Radiopharmaceuticals are used primarily for diagnostic and physiological function studies. Decay scheme information is important to establish the internal radiation dose received by the patient. Radionuclides for which better decay scheme data are needed are identified. Protons, alphas, pions, neutrons, and heavy nuclei such as Si-28 and A-40 are all being studied or used for radiation therapy of cancer. Of these, the most widely used is neutron radiation therapy at about 8 centers in the United States, 22 worldwide. The nuclear data needed are total and partial neutron cross sections for the elements that compose tissue and for dosimeter materials up to about 60 MeV.

ISSN:0033-7579    

DOI:10.1080/00337578608208346

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Neutron beams in the tens of MeV range are widely used in biomedical applications. At these energies the reaction channels open to charged particles increase compared to the situation prevailing below about 15 MeV. An extensive program to measure charged particle products on tissue-resident elements (H, O, C, and N) has been carried out at Crocker Nuclear Laboratory. The particles detected include protons, deuterons, tritons, helium-3 and alphas, measured over a wide angular range for neutron energies of 27.4, 39.7, and 60.7 MeV. Good agreement is found in comparison with charge symmetric proton-induced energy spectra (such as in (p,d) vs. (n,d)). Kerma have been obtained at the three energies for each nucleus including elastic recoil contributions. The use of sum rules to obtain the missing (non-elastic) contribution from heavier fragments is examined. These experimental kerma values are found to be considerably different than predictions by several authors. Recent calculations by Brenner and by Dimbylow are in better agreement with the experimental kerma.

ISSN:0033-7579    

DOI:10.1080/00337578608208347

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Half-lives and Pnvalues are presented for 38 precursors among the low yield fission products. Pnvalues are based on a beta-neutron coincidence technique.

ISSN:0033-7579    

DOI:10.1080/00337578608208348

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Delayed-neutron spectra from thermal neutron-induced fission of U-235 have been measured over the neutron energy range, .01–2.0 MeV, for delay times following fission ranging from 0.17–85.5 s. A helium jet system was used for the rapid transport of fission products to a low-background area, where the spectra were determined from beta-neutron correlations using the neutron time-of-flight method.

ISSN:0033-7579    

DOI:10.1080/00337578608208349

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The beta-decay energy of 16 neutron-rich nuclei in the mass region around A = 100 has been measured recently at the mass separators LOHENGRIN and OSTIS of the Institute Laue-Langevin in Grenoble by means of βγ-coincidence techniques. The results obtained are compared with the values given in a recent mass compilation and with the predictions of different theoretical mass formulae.

ISSN:0033-7579    

DOI:10.1080/00337578608208350

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Evaluated fission-product yield and decay data have been used to describe 105 delayed neutron precursors explicitly in point reactor kinetics calculations. Results calculated for235U thermal fission show that rod-drop reactivity values obtained from kinetics calculations with 6-group precursor data are considerably higher than those calculated with explicit delayed-neutron precursor data. The calculated kinetics associated with positive reactivity steps are significantly different.

ISSN:0033-7579    

DOI:10.1080/00337578608208351

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Geochemical analyses of oil bearing formations, based on nuclear techniques, are often limited by the current level of uncertainties on neutron cross section data. The problems created for nuclear geochemistry are most acute in the areas of high energy neutron scattering, inelastic neutron scattering gamma-ray production, and production of prompt gamma rays and delayed activations generated by (n,p) and (n,α) reactions for neutron energies up to 14 MeV. We will present examples illustrating the ways in which spectroscopic measurements are used for geochemical applications and how the uncertainties in the nuclear cross section data affect the usefulness of the results. Particular elements that cause significant problems in the analysis are emphasized.

ISSN:0033-7579    

DOI:10.1080/00337578608208352

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

An analytic, approximate formulism is described that provides reasonable estimates of neutron and high energy photon yields from targets of any material and thickness. Data on Cu and Ta are presented.

ISSN:0033-7579    

DOI:10.1080/00337578608208353

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The117mSn(4+)DTPA has been shown to have high uptake in cortical bone with negligible soft-tissue deposition. The long half-life (14 d) of117mSn and its emission of abundant short-range Auger and conversion electrons, make117mSn(4+)DTPA an attractive therapeutic agent for bone tumors. The necessary nuclear data for production of clinical quantities of117mSn using Sb(p,2pxn) reactions at BLIP was obtained. The excitation functions for121Sb(p,2p3n) and123Sb(p,2p5n) reactions in the regions of 43 ≤Ep≤60 MeV were measured and compared with predicted values obtained from semi-empirical formulae given by Silberberg and Tsao.117mSn is routinely produced at ORNL by thermal neutron activation of116Sn. We have investigated the possibility of improving the specific activity of the reactor-produced117mSn by irradiating enriched116Sn and117Sn in the core of the HFBR. Our results indicate that, due to a strong absorption resonance at En110 eV, better specific activity for reactor-produced117mSn can be obtained by irradiating natural tin in the core of a reactor.

ISSN:0033-7579    

DOI:10.1080/00337578608208354

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Recently evaluated and model estimated precursor data are used with preliminary ENDF/B-VI fission yields to calculate total and time-groupvdand spectra.

ISSN:0033-7579    

DOI:10.1080/00337578608208355

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor