Atomic masses of the isotopes C13, N14, N15

We present the results of new mass-spcttrographic measurements of the atomic masses of C¹³, N¹⁴ and N¹⁵. We show the internal consistency for the mass values of these isotopes obtained from different sets of mass doublets. The measurements were performed under conditions climinating systematic errors. We describe the method for precision adjustment of the ion-optical system. The values obtained for the masses of C¹³, N¹⁴ and N¹⁵ are 13.007491 ± 3·10^–6 and 14.007527 ± 4·10^–6 amu and 15.004890 ± 5·10^–6 amu. which is in good agreement with the values recently published by Nier and co-workers. This data is higher than the average data obtained from nuclear reactions and by statistical analysis. The difference in the values is explained by the inexact measurement of the Q-values used in calculating the masses of the parent isotopes n_o, H. D. He⁴ and C¹², and of the isotopes C¹³, N¹⁴ and N¹⁵.In conclusion the authors express their gratitude to I.G. Gvertseteli and V.K. Tskhakaia for making available the enriched C¹³ isotope, as well as to P.S. Brostiuk and M.I. Dzkuia for practical help with the work.     

Influence of Cavitation on the Working Surfaces of the Cylinder–Piston Group in a Diesel Engine during Maintenance

Russian Engineering Research - When a diesel engine runs on water–fuel emulsion, carbon deposits break down on account of microimpact by the fuel droplets in the emulsion. The evaporation of...     

Recent progress on cooled avalanche photodiodes for single photon detection

Abstract

Recent results on the properties of cooled avalanche photodiodes for single photon detection are presented. Results from Hamamatsu silicon photodiodes, originally developed as radiation-hard photodetectors for high energy physics experiments, are extremely encouraging. Gains of approximately 10,000 can be achieved with the APD operating in proportional mode. Together with a low noise amplifier they allow photon counting with extremely high efficiency and very low noise making cold APDs almost ideal single photon detectors. Operation of APDs in Geiger mode is also reported, together with measurements of detection efficiency and noise as function of operating voltage. Prospects and hopes for future work are briefly summarized.