Use Of Bremsstrahlung Research Articles

The dependence of AKR production on the intensity and energy spectra of auroral bremsstrahlung

Our limited knowledge of the energy dependence of electron precipitation associated with auroral kilometric radiation (AKR) production is improved with the use of bremsstrahlung x‐ray measurements. Simultaneous observations of bremsstrahlung x‐rays above 2 keV from the Polar Ionospheric X‐ray Imaging Experiment (PIXIE) on the POLAR satellite are compared with the frequency distributions of AKR waves measured with the Plasma Wave Instrument (PWI) on the GEOTAIL satellite. Various AKR characteristics such as the low‐ and high‐ frequency cutoffs and the frequencies at peak intensity are compared with various x‐ray parameters such as the magnetic local times of emission, the total intensities, and the spectral shapes. In particular, it is found that higher fluxes of x‐rays occur when the various cutoffs are at lower frequency. Also, higher AKR cutoff frequencies are associated with higher e‐folding x‐ray energy spectra.

Economic aspects of the use of bremsstrahlung in radiation technology

Economic aspects of the use of bremsstrahlung in radiation technology

Use of Bremsstrahlung in the Measurement of the Efficiency of Solid State Detectors below 5 keV

Atomic-field bremsstrahlung produced by the bombardment of atoms by an electron beam of 5-10 keV energy provides a continuous x-ray source which is suitable for the measurement of the relative efficiency of solid state detectors in the energy region below 5 keV. The relative efficiency as a function of photon energy can be obtained by normalizing the observed spectrum to the theoretical bremsstrahlung cross section. In this paper we will present an example of this technique using a thin film target and a gas beam target to illustrate some of the problems and to demonstrate the potential of this technique.

Total photoneutron cross sections for 12C and 19F

The total photoneutron cross sections for 12C and 19F were measured from threshold to 33 and 19 MeV respectively, with the use of bremsstrahlung from a linac and by direct detection of the neutrons. The yield curves were analysed using the variable-bin Penfold and Leiss unfolding technique, and the least-structure method of Cook. The 12C data are in good agreement with available results; the 19 F( γ, χn) cross section shows considerable fine structure, not observed in neighbouring odd-mass nuclei.

On the use of bremsstrahlung for the determination of tritium in aqueous and organic systems

The bremsstrahlung method for the determination of beta radioactivity without gamma radiation is extended to the case of tritium. Using cells made from light materials, excellent results and rough agreement with theoretical estimates were obtained for water containing millicurie amounts of tritium. Applications to self-diffusion studies on water and labelling experiments are briefly described.

Absolute Cross Sections of the (γ, n) Reaction for Cu63, Zn64 and Ag109

The photonuclear reaction cross section of Cu/sup 63/ ( gamma , n)Cu/sup 62/ has been frequently used as the standard for the ( gamma , n) reactions, but measured values by many workers do not agree with one another and can be roughly divided into two groups, namely, about l00 mb group and about 50 mb group. It appears that the former group contains the values obtained mainly from measurements through use of bremsstrahlung, while the latter were obtained mainly with Li(p, gamma ) gamma rays. Attempts were made to re-determine the ( gamma , n) cross section for copper, zinc, and silver by Li(p, gamma ) gamma rays. Absolute measurement or gamma quanta was performed by Hough's method, and reaction yields were determined by the activation method in which the absolute numbers of activated nuclei in samples were determined by measuring the BETA ray with a 4 pi proportional counter and applying the method of extrapolation.'' The cross sections of Cu/sup 63/, Zn/sup 64/, and Ag/sup 109/ for l7.6-Mev gamma rays were foundto be 42.5 mb plus or minus 15%, 23.3 mb plus or minus 18%, and 61.5 mb plus or minus 16%, respectively. Experimental cross sections so farmore » obtained by many workers are compiled, and discussions are given. (auth)« less