Wave-length Measurement of Gamma-Rays from Radium and its Products

1931 ◽  
Vol 37 (4) ◽  
pp. 447-447 ◽  
Author(s):  
Luville T. Steadman
Keyword(s):  
Gamma Rays ◽  
Wave Length ◽  
Length Measurement

scholarly journals Precision Wave-Length and Energy Measurement of Gamma-Rays fromAu198with a Focusing Quartz Crystal Spectrometer

1948 ◽  
Vol 73 (11) ◽  
pp. 1392-1394 ◽  
Author(s):  
Jesse W. M. DuMond ◽  
David A. Lind ◽  
Bernard B. Watson
Keyword(s):  
Gamma Rays ◽  
Quartz Crystal ◽  
Wave Length ◽  
Energy Measurement ◽  
Crystal Spectrometer

scholarly journals The physical basis of the biological effects of high voltage radiations

1934 ◽  
Vol 146 (859) ◽  
pp. 867-879 ◽  
Keyword(s):  
Gamma Rays ◽  
High Voltage ◽  
High Speed ◽  
Biological Effects ◽  
Wave Length ◽  
X Rays ◽  
Absorbed Energy ◽  
Electron Production ◽  
The Mean ◽  
Complex Manner

Although both the physical properties of penetrating X-rays and gamma rays and their biological effects have been carefully studied, the mechanism of the action of the rays is little known. The question of the relative effects of the same absorbed energy per cubic centimetre of tissues when different wave-lengths are used is a particularly important and obscure one. The present paper is attempt to apply recent theories of high-speed electron production to this problem. Radiations, such a high voltage X-rays or gamma rays, on suffering real absorption give rise to high speed negative electrons, either in photoelectric absorption whereby nearly the whole of the quantum is transferred to the electron, or in a Compton recoil process in which only part of the energy is transferred. The mean fraction given to the electrons rises gradually as the radiations become more penetrating. The relative importance of these two types of process varies in a complex manner with the wave-length and absorbing materials, but in this paper it is proposed to confine discussion to the absorption of “hard” radiations in light elements, of which living materials are mostly constructed.

scholarly journals Absorption of radium (B+C) gamma-rays

1945 ◽  
Vol 183 (994) ◽  
pp. 338-355 ◽  
Keyword(s):  
Gamma Rays ◽  
Electron Pair ◽  
Gamma Ray ◽  
Wave Length ◽  
Photoelectric Effect ◽  
Pair Formation ◽  
Photoelectric Absorption ◽  
Absorption Coefficients ◽  
Length Range ◽  
Effective Wave

New measurements of the absorption of filtered gamma-rays from radium (B + C) in aluminium, carbon and lead have been made. A small condenser type of ionization chamber has been used, which overcomes many of the difficulties usually inherent in this kind of measurement. Detailed consideration has been given to the corrections which must be applied to ionization measurements before absorption coefficients can be calculated. From the most recent theories of absolution by scattering, photoelectric effect, and electron pair formation, total absorption coefficients for lead over the wave-length range concerned have been calculated. The problem of the effective wave-length of a filtered heterogeneous gamma-ray beam is discussed in some detail, and a proposed method of estimation put forward. Comparison of the calculations of µ / ρ with the experimental figures indicates that the photoelectric absorption rises more rapidly with increasing wave-length than is predicted by theory.

scholarly journals The coincidence method for the wave-length measurement of absorption bands

1923 ◽  
Vol 94 (662) ◽  
pp. 335-335
Keyword(s):  
Wave Length ◽  
Length Measurement ◽  
Coincidence Method ◽  
Absorption Bands ◽  
The Mean

(1) Measurements of the absorption bands of pigments by means of the ordinary spectroscope are found to be inaccurate, because of the breadth of the bands and the indefiniteness of their margins. (2) The adjustment of two similar absorption bands into coincidence is found to be effected with considerable accuracy. If then a spectroscope is designed in which two spectra are seen side by side, on looking down the eye piece, but reversed in direction with one another, the measurement of the mean wave-length of the absorption bands can be accurately carried out.

scholarly journals Double wave-length measurement of membrane potential in excitable membrane

1990 ◽  
Vol 11 (2) ◽  
pp. 9-15
Author(s):  
Tomoo SATO ◽  
Yasumitsu MIYAZAKI ◽  
Hiroji KUCHIWAKI
Keyword(s):  
Membrane Potential ◽  
Wave Length ◽  
Length Measurement ◽  
Excitable Membrane

The inactivation of plant viruses by radiations

Parasitology ◽  
1942 ◽  
Vol 34 (2) ◽  
pp. 227-237 ◽  
Author(s):  
D. E. Lea ◽  
Kenneth M. Smith
Keyword(s):  
Virus Particle ◽  
Gamma Rays ◽  
Potato Virus ◽  
Structural Changes ◽  
Wave Length ◽  
Plant Viruses ◽  
X Rays ◽  
Virus Size ◽  
Size Estimates

Experiments are described on the inactivation by gamma-rays, X-rays, and alpha-rays of the viruses of tomato bushy stunt, tobacco necrosis, tobacco ringspot, tobacco mosaic and potato virus X. Within the errors of the experiment the inactivation curves appear to be exponential, and the inactivation doses increase in the order gamma-rays, X-rays, of wave-length 1·5 A., X-rays of wave-length 8·3 A., and alpha-rays.A theory is given explaining these results and correlating the inactivation dose with the virus size. Estimates of the sizes of the viruses obtained from the radiation experiments he within the range of the sizes given by other methods, but are somewhat lower than the most probable sizes. Possible explanations of the discrepancy which are discussed are (a) the virus particle is not the molecule, in the sense of the smallest infective unit, or (b) certain structural changes in the virus molecule produced by the radiation may still leave it infective. Some of these may perhaps show themselves as mutations.

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