Thesis (M.A.Sc.) -- University of Toronto, 1995.
|Series||Canadian theses = -- Thèses canadiennes|
|The Physical Object|
|Pagination||2 microfiches : negative. --|
1. Introduction. Helium can have a pronounced effect on the irradiation damage of materials and may be an important reason for the degradation of reactor structural elements,,,.The helium embrittlement and swelling resulted from the helium production via the transmutation reaction (n, a) during neutron irradiation, has been a cause of much concern in terms of safety and structural Cited by: 4. Midplane cross-section of a row of collimating alpha collector probe h e d. The stack of 10 layers of 1 pm nickel foil is wrapped onto the inner spool, which is then inserted into an outer shell. Positron-annihilation spectroscopy (PAS) has been used for the study of the behavior of helium in nickel. Helium has been homogeneously implanted in pure nickel by α-particle irradiation with use of a cyclotron. Post-implantation positron-lifetime and Doppler-broadened line-shape measurements have been carried out as a function of the isochronal annealing temperature on the samples containing Cited by: An escaping alpha collector probe has been developed for the deuterium-tritium (DT) phase of the Tokamak Fusion Test Reactor (TFTR) to complement the results of the lost alpha scintillator.
Alpha collector probe Detection technique The alpha collector probe [ is based on the foil deposition technique originally proposed by Langley . Similar methods have been previously used on TFTR to collect DD fusion produced tritons (71, and on the Joint European Torus (JET) to collect 3He. Absolute measurements of the alpha particle flux time-integrated during a low current discharge to a foil collector probe, also located 90° below the midplane, agreed with theoretical calculations of the escaping alphas (Herrmann et al., ). Download: Download full-size image; Figure Fraction of alpha particles collected by a. An escaping alpha collector probe has been developed for TFTR`s DT phase to complement the results of the lost alpha scintillator detectors which have been operating on TFTR since Bailey, Paul, Armour, D. G., Karpuzov, D. S. and Carter, G. () Helium trapping in nickel and the use of the helium probe as a technique for defect and gas agglomeration studies. Radiation Effects, 78 (). pp. ISSN Metadata only available from this repository.
Total thermal resistance is, then, found as (14) R= 1 h p – w + t k w + 1 h b – w, where h p–w is the Kapitza conductance between the liquid helium in the probe and the probe wall, h b–w is the Kapitza conductance between the probe wall and helium bath, t is the wall thickness of the probe and k w is the thermal conductivity of the wall. GHS Hazard and Precautionary Statements. Hazard Statements: HHH May cause an allergic skin reaction. Suspected of causing cancer. Causes damage to organs through prolonged or repeated exposure. The helium measurements were made using a isotope dilution process, a technique with very high accuracy 8, 9. To ensure that loss or gain of helium across the specimen surfaces did not perturb the measurement, the specimens were acid-etched before measurement to remove surface material to a depth greater than the maximum alpha particle range. After hydrogen, helium is the second most abundant element in the universe. It is present in all stars. It was, and is still being, formed from alpha-particle decay of radioactive elements in the Earth. Some of the helium formed escapes into the atmosphere, which contains about 5 parts per million by volume.