B. Schlenk

A study on the etching properties of electron-irradiated plastic track detectors

Abstract The variations of the bulk etching rate of electron-bombarded CN, CA, CAB, PC and PET sheets were studied as a function of electron dose and etching temperature. A conclusion was made that in the plastics under study a radiation-damaged region produced, either by an electron beam or a heavily ionizing nuclear particle display, to a certain extent, analogous etching properties. It was shown that the ratio of the etching rates of an electron-bombarded and an unirradiated sheet increases with the increase of the etching temperature for PC and PET, and with the decrease of etching temperature for CN and CA. Similar temperature dependences were obtained for the ratio of track– and bulk-etching rates (i.e. for registration sensitivity) if the plastic sheets were irradiated with heavier nuclear particles. Our results seem to confirm the assumption that the delta electrons may play an important role in the formation of primary nuclear particle tracks in plastic track detectors.

Kα/Kβ X-ray intensity ratios and K-shell ionisation cross sections for bombardment by electrons of 300-600 keV

The Kalpha /Kbeta intensity ratios were measured for X-rays from Fe, Co, Ni, Cu, Se and Y produced by electrons of 300-600 keV by using a Cockcroft-Walton accelerator. Absolute K-shell ionisation cross sections were also determined for Cu and Se.

Study of the L-shell ionisation of gold by 3.0-18.2 MeV nitrogen-ion bombardment

The angular distributions of the L X-ray line intensities of gold have been measured by nitrogen-ion bombardment in the 3.0-18.2 MeV energy region. From the measured data absolute subshell ionisation cross sections and the anisotropy parameter of the Ll X-ray line have been deduced. Comparing the experimental data with the first-order perturbation theories significant deviations have been found, especially for the L2-subshell ionisation cross section and for the anisotropy parameter of the Ll X-ray line.

Investigation of inner-shell ionization by electron impact in the 60–600 keV energy region

Total L X-ray production and total K-shell ionization cross sections have been measured for Se, Ag and Sb by electron impact ionization in the 60–600 keV bombarding energy region. Experimental results have been compared with the theoretical predictions of the PWBA, those of the BEA and in the case of K-shell those of the virtual photon method as well. In the investigated energy and atomic number region the relativistic PWBA gave the best agreement with our experimental data.

Inner-shell ionization by electrons in the 300–600 keV region

A measuring set-up at a Cockcrof—Walton accelerator is described for the determination of electron impact inner-shell ionization cross-section detecting the X-rays by Si(Li) solid-state detector. The K-shell electron impact ionization cross-sections for Ag in the region from 300 to 600 keV were determined and compared with the earlier experimental and the calculated theoretical values.

19F(d, α)17O angular distributions at Ed = 300–650 keV

Abstract Angular distributions of the α 0 , α 1 , α 2 and α 3 groups from the reaction 19 F(d, α ) 17 O have been measured at ten different energies in the range E d = 300–650 keV with a plastic track detector and/or a semiconductor detector. The angular distributions which are energy dependent and asymmetrical about 90°, show the characteristic features of the compound nucleus mechanism. The experimental data have been analysed in terms of Legendre polynomials. The absolute cross section values have been determined for the α -groups investigated.

Investigation of the projectile atomic number dependence of the L-subshell ionization

Abstract Relative L-subshell ionization cross sections have been measured using a series of ions at a fixed collision velocity in order to study the projectile nuclear charge dependence. Thin Sm, Er, and Au targets were bombarded by 2 H + , 4 He + , 12 C + , and 14 N + ions MeV u impact energy. The cross sections were normalized to the data obtained by deuterons. The experimental results have been compared with calculations in the perturbed stationary state approximations with Coulomb deflection, binding and relativistic corrections included (CPSSR) as well as with the recent second order calculations. Particularly large discrepancies have been found for the L 2 subshell comparing the CPSSR results with the measured values. These discrepancies have been reduced significantly by the inclusion of the second order effects.

The Coulomb deflection effect on the L3-subshell alignment in low-velocity proton impact ionisation

The A2 alignment parameter of the L3 subshell of gold has been determined by measuring the angular distribution of the Ll/Lgamma intensity ratio following proton impact ionisation in the 0.25-0.60 MeV energy range. The experimental results make it clear that the minimum of the alignment parameter at low energies found earlier for He+ impact also exists in the case of proton impact ionisation.

L3-subshell alignment of gold by C+ and N+ impact ionisation

Measurements of the L3-subshell alignment of gold by low velocity C+ and N+ impact are reported. The alignment parameter has been found to be positive and it is surprisingly large (A2=0.47+or-0.09) for 2.4 MeV N+ ions.

Experimental investigation of the angular distribution of characteristic x-radiation following electron impact ionisation

There are a number of theoretical predictions that the characteristic X-radiation following electron impact ionisation is partially polarised and has a non-isotropic angular distribution. The angular distributions of L and K radiation of selenium following electron impact ionisation at bombarding energies of 600 and 300 keV, and that of the M, Ll, Lalpha , Lbeta , Lgamma radiations of bismuth at bombarding energies of 100 and 300 keV have been measured. Within experimental error these radiations were found to be isotropic.