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[en] A description is presented of a linear time-of-flight mass spectrometer which was constructed to study, first, the dissociation of molecule-ions produced by electron impact in conditions as 'clean' as possible, and, later, under well-defined kinematic conditions, also possibly with ionizing agents. (U.K.)
Source
Daly, N.R. (ed.) (Ministry of Defence, Aldermaston (UK). Atomic Weapons Research Establishment); p. 1256-1259; ISBN 0 85501 307 9; 
; 1978; p. 1256-1259; Heyden for the Institute of Petroleum; London; 7. international mass spectrometry conference; Florence, Italy; 30 Aug - 3 Sep 1976
; 1978; p. 1256-1259; Heyden for the Institute of Petroleum; London; 7. international mass spectrometry conference; Florence, Italy; 30 Aug - 3 Sep 1976
[en] A versatile apparatus designed for research in molecular physics has been developed recently in our laboratory. It is now used to perform experiments in translational spectroscopy. The principal feature of this apparatus is the high resolution and reliability of the electronic circuit designed for the measurement of the time of flight of the ions (approximately 1 ns over any time to be measured). A minicomputer is used to collect the data, drive the spectral display of the times of flight and perform the analysis of the data. The electronic circuit, composed of easily available components is described in detail. (Auth.)
Journal
International Journal of Mass Spectrometry and Ion Physics; ISSN 0020-7381; ; v. 30(1); p. 57-62
; v. 30(1); p. 57-62
[en] The kinetic energy distribution of N+ ions produced by dissociative ionization of N2 was measured by high-resolution measurement of drift times in a time-of-flight mass spectrometer. The apparatus, completely developed in our laboratory, is described in detail; the high resolution and reliability of the electronic hardware allow the measurement of the drift time of ions (1-100 μs) with a precision of approx. 1 ns. A computational analysis of the drift time distributions obtained at different electron energies in the range 27-50 eV enables the corresponding kinetic energy distributions to be found and hence the excitation kinetic energies to be deduced. The zero kinetic energy appearance potentials of four well-defined N+2 states are 26.2, 27.7, 34.4 and 38.7 eV. An experimental upper limit of 100 ns has been found for the mean life to the C2Σ u+ state. (orig.)
Journal
International Journal of Mass Spectrometry and Ion Physics; ISSN 0020-7381; ; v. 36(2); p. 213-220
; v. 36(2); p. 213-220
[en] Introduction: The objective of this study is to provide reference values of radiation doses absorbed by surgeons during open reduction and internal fixation of distal radius fractures. Methods: We prospectively evaluated radiation exposure during surgery for distal radius fracture between May and December 2015. Exposure was evaluated in two surgeons using dosimeters in thorax, neck, and wrist. A relative radiation index for each surgery was calculated to identify the differences among sites and to establish reference values for radiation monitoring. Results: Results of surgery performed in 50 patients were evaluated. Surgical procedure averaged 40 minutes (SD 2.06), and there were no statistically significant differences between both surgeons (p=0.043). C-arm exposure time averaged 75 seconds. There were significant differences between surgeons (p=0.007) or among sites (p<0.05). Radiation in the thorax was smaller (protected with a lead vest, 0.04 mSv) than in the other two sites (not protected with lead): wrist 0.017 mSv and thyroid 0.18 mSv. Conclusions: During open reduction and internal fixation of distal radius fractures, surgeons are exposed to direct radiation during fluoroscopy, which varies according to the exposure site and it is not uniform among surgeons. The amount of radiation received by surgeons, when only distal radius fractures are considered, cannot be associated with increased risk of cancer or malignancy development. (authors)
[es]
Introducción: El objetivo de este estudio es proveer valores de referencia de dosis de radiación absorbida por el cirujano en la reducción abierta y fijación interna con placa volar de fracturas inestables de radio distal. Materiales y Métodos: Entre mayo y diciembre de 2015, se evaluó prospectivamente la exposición a la radiación de dos cirujanos, usando dosímetros en tórax, cuello y muñeca en las cirugías de fracturas inestables de radio distal. Se construyó un índice relativo para cada cirugía a fin de identificar las diferencias entre los sitios y establecer valores de referencia para el monitoreo de la exposición. Resultados: Se evaluaron los resultados en las cirugías de 50 pacientes. El procedimiento quirúrgico promedió 40 minutos (DE 2.06); se hallaron diferencias estadísticamente significativas entre los dos cirujanos (p = 0,043). El tiempo promedio de exposición del arco en C fue de 75 segundos y difirió significativamente entre los cirujanos (p = 0,007) y entre los sitios (p <0,05). Hubo menos radiación en el tórax (protegido con chaleco de plomo, 0,04 mSv) que en los otros dos sitios (no protegidos): muñeca 0,017 mSv y tiroides 0,18 mSv. Conclusiones: En la reducción abierta y fijación interna de fracturas de radio distal, los cirujanos están expuestos a la radiación directa durante la fluoroscopia, la cual varía conforme el sitio de exposición y no es homogénea entre los profesionales. La cantidad de radiación recibida por los cirujanos, cuando se consideran aisladamente las fracturas de radio distal, no puede asociarse a un mayor riesgo de cáncer o desarrollo de malignidad. (autores)Journal
Revista de la Asociacion Argentina de Ortopedia y Traumatologia (Online); ISSN 1852-7434; ; v. 82(4); p. 271-277
; v. 82(4); p. 271-277
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