Örjan Nilsson

L subshell ratios in some pure E2 transitions

Abstract The L subshell conversion line intensity ratios have been studied for four 2 + → 0 + transitions (86.79 keV in 66 160 Dy, 80.57 keV in 68 166 Er, 84.26 keV in 70 170 Yb and 100.09 keV in 74 182 W) and for the 5 2 − → 1 2 − 99.07 keV transition in 74 183 W. The L II /L III ratios obtained agree very well with theory but the L I /L II and L I /L III ratios are 5–9% higher than the theoretical ratios. Deviations of the same magnitude have also been reported by other research groups.

DEVELOPMENT OF PARALLEL PLATE CHANNEL MULTIPLIERS FOR USE IN ELECTRON SPECTROSCOPY.

Abstract A simple method for designing parallel plate electron multipliers is described. Semiconducting and secondary emitting layers are deposited onto glassplates by rf-sputtering, and by placing two plates face to face with a separation of 0.6 mm a parallel plate multiplier is formed. The multipliers have a high gain (>10 9 ) and give output pulses with a very narrow pulse height distribution. The multipliers are used as detectors in electron spectrometers. The small dimensions imply that a large number of multipliers may be placed in the focal plane and used simultaneously.

K/L, LIII/MIII and M/(N + O + P) ratios in pure E2 transitions☆

Abstract Accurate measurements have been performed on relative K, L, M and (N + O + P) internal conversion line intensities of some pure E2 transitions in nuclei in the rare-earth region. The results are compared with theoretical values obtained from the calculations by Rose, Sliv and Band, Hager and Seltzer and by Bhalla. Good agreement between experiment and theory is found for the K/L ratios, while the experimentally obtained LIII/MIII ratios are somewhat lower than predicted by theory.

The low-energy internal conversion spectrum of 182W from the decay of 182Ta

Abstract The internal conversion spectrum of low-energy transitions in 182W following the decay of 182Ta has been studied using the 50 cm, iron-free spectrometer at Uppsala. Relative conversion line intensities are given together with internal conversion coefficients, multipolarities and mixing ratios. The energies of the 32 and 43 keV transitions have been determined with high precision. The existence of two previously reported transitions could not be confirmed.

DETERMINATION OF RELATIVE INTENSITIES OF M INTERNAL CONVERSION LINES IN PURE E2 TRANSITIONS.

Accurate measurements have been performed on the relative intensities of the M internal conversion lines of three pure E2 transitions in nuclei in the rare-earth region. The results are compared with theoretical values obtained from the calculations by Bhalla and by Hager and Seltzer. Discrepancies of about 6% between experiment and theory are reported for the MI/MII and MI/MIII ratios of the 80.57 keV transition in 166Er. The MII/MIII ratios of the 84.26 keV transition in 170Yb and of the 100.09 keV transition in 182W are significantly lower than predicted by theory.

Internal conversion studies of the 114 keV transition in175Lu

Measurements of the conversion line intensities, the directional correlation and the conversion probability for the 114 keVM1+E2 transition in175Lu are reported. TheE2 admixture, determined from relativeK andL intensities, is (19.2±0.2)%. The theoreticalLI internal conversion coefficient is found to be about 8% too low relative theK,LII andLIII conversion coefficients.

Array detectors and extended source used in a double focusing beta spectrometer

Abstract The 50-cm iron-free beta spectrometer at Uppsala has been furnished with an array of close-lying semiconductor detectors and an extended source arrangement. The combined detector and source system increase the amount of information per time-unit more than 100 times. A description of the detector and source arrangements is given together with some applications.

Precision measurements on the 296 keV and 316 keV transitions in 192Pt

Abstract A recently reported L II anomaly in Pt is removed. Precise determinations of the energies of the 296 keV and 316 keV transitions are obtained. The L subshell ratios for the 316 keV E2 transition are measured.

Pressure dependence of gain and background for parallel plate channel multipliers

Abstract A pressure dependence of the amplification and spontaneous pulse count rate of parallel plate channel multipliers is established. The variation in gain is quite small and does not cause any problems for the practical use of the multipliers. At pressures below 10−5 torr the pressure dependence of the background can be neglected also.

Relative internal conversion electron intensities of the 113 keV transition in 177 Hf

The intensities of the internal conversion lines of the 113 keVM1 +E2 transition in177Hf have been measured. From comparison with theoretical conversion coefficients the transition has been found to be (95.2 ± 0.5)%E2 corresponding to ¦δ¦=4.5 ± 0.3. The theoreticalLI andMI conversion coefficients used in the comparison have been increased by 5% according to the result that for pureE2 transitions in the deformed region theLI/LII,LI/LIII,MI/MII, andMI/MIII theoretical ratios are too low (∼5%). Moreover, the present result indicates that theLII/LIII andMII/MIII ratios obtained from the tabulations by Hager and Seltzer and from the computer program by Pauli are too high (1–2%).