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A V Kuehner

Publications and source records attributed to A V Kuehner.

7 recordsLinked to original sources
PubMed1991

A system for simultaneous exposure of small animals to 60-Hz electric and magnetic fields.

Equipment designed for simultaneous exposure of rodents to 60-Hz electric and magnetic fields is described. Three identical systems were constructed, each capable of continuous exposure of 256 rats or 640 mice to a nominal electric field at less than 50 kV/m, and to horizontal and vertical magnetic fields at less than 1 mT. Design features, construction details, and results of various tests of the systems are described. Tests were made: of phase relations between electric and magnetic fields; of uniformity of electric and magnetic fields; of changes across time in electric-field intensity as a result of animals' soiling of cages and various washing routines; of resistance of bedding material during humid and dry conditions; and of acoustic noise due to background, to field-generation equipment, and to air conditioning equipment. The results demonstrated that fields were effectively generated but that significant and troublesome changes in electric-field intensity occurred because of cage-soiling. However, when cages were frequently cleaned, field intensities were consistent from one exposure to another.

Animals↗
PubMed1980

Stopping power and radial dose distribution for 42 MeV bromine ions.

Linear energy transfer restricted in radius (LETr) and total linear energy transfer (LET infinity) were determined for 42 MeV bromine ions in tissue-equivalent gas. A variable pressure cylindrical ionisation chamber was used. Dose as a function of distance from the ion's path was also determined using a mesh wall ionisation chamber placed inside the cylindrical chamber. The range of distances studied was from 5 to 710 A in simulated tissue of unit density. Experimentally obtained values of radial dose were compared with calculations made using Paretzke's program. Stopping power for these ions in tissue-equivalent gas was extrapolated from proton stopping power in constituent gases. In this calculation the effective charge of the ions was obtained from the formula given by Dimitriev and Nikolaev. This calculated value was 6.3 x 10(4) MeV g-1 cm2. The experimentally determined value was 7.3 x 10(4) MeV g-1 cm2. The discrepancy between calculated and experimental values may be due to uncertainty in the determination of the effective charge of the incident ions. Uncertainty on the experimental value of LET infinity was estimated to be +/- 5% (one standard deviation).

Bromine↗
PubMed1975

Experimental determination of W for oxygen ions in nitrogen.

'Differential' and integral measurements were made of the W value (average energy required to form an ion pair) for oxygen ions in nitrogen gas. A variable pressure cylindrical ionization chamber with a differential pumping section was employed. The average energy deposited per particle in the chamber was determined by integrating the energy spectrum measured with a heavy ion solid state detector. In the integral measurement of W, the particle was completely stopped in the chamber and the total ionization produced in the chamber was measured. The integral W value for 34-5 MeV oxygen ions was found to be 38-6 +/- 0-54 eV per ion pair. For 'differential' measurements, the pressure in the chamber was raised to 0-003, 1, 5, 15 and 20 Torr; and measurements of ionization currents and average energy deposited per particle were made at each pressure. From differences between these measurements 'differential' W was found. The average value of fifteen 'differential' W values was found to be 38-6 +/- 1-16 eV per ion pair.

Ions↗