[en] Tellurium powder in improved targets is bombarded with a cyclotron beam to produce ¹²³Xe. Flowing gas streams carry the ¹²³Xe through one cold trap which removes contaminants to another cold trap which removes ¹²³Xe that subsequently decays to ¹²³I. During this bombardment energy is deposited in the target material causing its temperature to rise. Some of the tellurium vaporizes and subsequently condenses on surfaces that are cooler than the vaporization temperature. Provision is made for the repeated bombardment of this condensed tellurium

[en] Bombarding a cesium heat pipe with high energy particles causes a spallation reaction which produces vapors of ¹²³Xe and contaminants. The contaminants are removed in a dry ice cold trap while the ¹²³Xe condenses in a liquid nitrogen trap where it decays to ¹²³I

[en] An experiment was performed to look for evidence of deuterium fusion in palladium. The experiment, which involved introducing deuterium into the palladium filter of a hydrogen purifier, was designed to detect neutrons produced in the reaction D-2 + D-2 yields He-3 + n as well as heat production. The neutron counts for deuterium did not differ significantly from background or from the counts for a hydrogen control. Heat production was detected when deuterium, but not hydrogen, was pumped from the purifier

No abstract available

No abstract available

[en] Chinese hamster V 79-S171 cells were maintained in exponential phase in 75 cm/sup 2/ T-flasks incubated in a humid atmosphere of 5% CO/sub 2/ in air at 37⁰C. The cells were trypsinized and the single cell suspension in a dilution tube was irradiated with neutrons or /sup 60/Co at dose rates of 0.02 or 0.05 Gy/min respectively. The dilution tube was placed in a copper coil through which a current of 20 A at a frequency of 2200 Hz produced a magnetic field with a peak strength of 0.08T. Cooling kept the cells between 25 C and 32 C during irradiation. After irradiation the cells were diluted to appropriate concentrations, plated in 60 mm dishes containing 6 ml of medium and incubated for one week. Counting of colonies of at least 50 cells showed surviving fractions at 6,8 and 10 Gy were smaller than the controls (a direct current of 15 A through the coil and an identical irradiation) by 30%, 100%, and 300% respectively for fast neutron irradiations. /sup 60/Co irradiations to 5, 10, 15, and 20Gy gave the same survival whether AC or DC currents were used. Possible mechanisms for this effect are presented

[en] If boron neutron capture therapy (BNCT) is to be widely used to treat patients with brain tumors, then a hospital-based neutron source must be developed. Accelerator neutron sources for BNCT have been proposed as alternatives to nuclear reactor beams. The ideal neutron source for BNCT is a monoenergetic neutron beam with a neutron energy that is above thermal energies but below ∼ 10 keV. The optimum neutron energy is currently being studied. The purpose of this paper is to report the results of a Monte Carlo analysis of the performance of an accelerator neutron source for the treatment of brain tumors by BNCT. The proton beam is identical. Thicknesses of moderators are identified that yield neutron energy spectra which produce within a head phantom distributions of absorbed dose approaching the distributions that would be attained with the above-mentioned ideal spectra

[en] The feasibility of producing high-purity ¹⁶⁷Tm by spallation for use in nuclear medicine was investigated. Lutetium-oxide powder and hafnium, tantalum and tungsten foils were irradiated with 590-MeV protons. Cross sections for the formation of ¹⁶⁷Tm and contaminating ¹⁶⁸ Tm were determined; the best target material was tungsten with cross sections averaging 49 and 0.39 mbarns for ¹⁶⁷Tm and ¹⁶⁸Tm, respectively. The average amount of ¹⁶⁸Tm from the tungsten target was 0.09% of the ¹⁶⁷Tm activity and this equals the lowest contamination achieved with low-energy proton and ⁴He-ion-induced reactions. (author)

[en] Deuteron reactions have been studied for the possibility of producing ²⁰¹Tl so that this radioisotope could be made as an adjunct to neutron therapy. The cross-sections for the (d,xn) reactions for ²⁰³Tl and ²⁰⁵Tl target nuclei have been measured for x=3, 4, and 5. From these data the yields of ²⁰¹Tl for a typical treatment day have been calculated

[en] Small bars of ceramic Ba2YCu3O(7-x) were fabricated and subjected to environments similar to those that might be encountered during some NASA missions. These conditions include ambient conditions, high humidity, vacuum, and high fluences of electrons and protrons. The normal state resistivity or critical current density (J sub c) were monitored during these tests to assess the stability of the material. When normal state resistivity is used as a criterion, the ambient stability of these samples was relatively good, exhibiting only a 2 percent degradation over a 3 month period. The humidity stability was shown to be very poor, and to be a steep function of temperature. Samples stored at 50 C for 40 min increased in normal state resistivity by four orders of magnitude. Kinetic analysis indicates that the degradation reaction is second order with water vapor concentration. It is suspected that humidity degradation also accounts for the ambient instability. The samples were stable to vacuum over a period of at least 3 months. Degradation of J sub c in a 1 MeV electron fluence of 9.7 x 10 to the 14th e(-)/sq cm was determined to be no more than about 2 percent. Degradation of J sub c in a 8.7 x 10 to the 14th p(+)/sq cm of 42 MeV protons was found to be grain size dependent. Samples with smaller grain size and initial J sub c of about 240 A/sq cm showed no degradation. while that with larger grain size and an initial J sub c of about 30 A/sq cm degraded to 37 percent of its original value