scholarly journals Stopping Power of Liquid Water for α-Particles

Nature ◽  
1949 ◽  
Vol 163 (4144) ◽  
pp. 526-526 ◽  
Author(s):  
R. K. APPLEYARD
Keyword(s):  
Liquid Water ◽  
Stopping Power ◽  
Α Particles

The differential stopping power of liquid water for α-particles

1956 ◽  
Vol 237 (1208) ◽  
pp. 28-38 ◽  
Keyword(s):  
Liquid Water ◽  
Capillary Tube ◽  
Water Film ◽  
Accurate Method ◽  
Particle Energy ◽  
Glass Tank ◽  
Stopping Power ◽  
Pass Through ◽  
Source Of Error ◽  
Α Particles

An accurate method is described for determining the differential stopping power of liquid water at α-particle energies between 4 and 6 MeV. α-Particles from a Th C ' source pass through a steel capillary tube, whose covered end lies just below the water surface in a wide glass tank. After traversing the water film above the capillary tube the α-particles are detected by a movable proportional counter. The curve of count against distance is first plotted. Then the thickness of the water film is increased by adding a weighed quantity of water to the tank and the curve is plotted again. The air equivalent of the added layer of water is then derived from the displacement of the curve. A source of error in the measurements is hysteresis of the angle of contact of the water with the walls of the glass tank, but a correction may be derived by varying the length of the water-glass-air boundary of the system, or the error may be eliminated by using dilute solutions of detergents. At an α-particle energy of 5.5 MeV, the differential stopping power of one molecule of water relative to the average atom of air is found to be 1.45 + 0.02, which is 0.02 less than the accepted value for an equivalent mixture of hydrogen and oxygen. The stopping power does not increase by more than 0.02 + 0.015 between 5.7 and 4.3 MeV.

The stopping power of liquid water

1951 ◽  
Vol 47 (2) ◽  
pp. 443-449 ◽  
Author(s):  
R. K. Appleyard
Keyword(s):  
Liquid Water ◽  
Stopping Power ◽  
Α Particles

ABSTRACTExperiments are described in which the stopping power of liquid water relative to air has been re-determined for 5 MeV. α-particles, using only a limited portion of the range. The results confirm those of earlier experimenters, who concluded that liquid water did not obey the Bragg law.

scholarly journals Measuring the stopping power of α particles in compact bone for BNCT

2015 ◽  
Vol 583 ◽  
pp. 012047 ◽  
Author(s):  
L Provenzano ◽  
L M Rodríguez ◽  
D Fregenal ◽  
G Bernardi ◽  
C Olivares ◽  
...  
Keyword(s):  
Compact Bone ◽  
Stopping Power ◽  
Α Particles

The theory of the influence of magnetic fields on the stopping power of gases for α-particles

1925 ◽  
Vol 22 (5) ◽  
pp. 773-776
Author(s):  
R. de L. Kronig
Keyword(s):  
Magnetic Fields ◽  
Experimental Test ◽  
Stopping Power ◽  
Α Particles

The purpose of this note is to calculate, on the basis of the assumptions which underlie the theory of the stopping of α-particles by matter, the influence of space quantization on this phenomenon. The results arrived at may be capable of an experimental test and will serve to illuminate these assumptions and to indicate their limitations.

scholarly journals On the range of α-particles in rare gases

1924 ◽  
Vol 106 (739) ◽  
pp. 622-632 ◽  
Keyword(s):  
Molecular Structure ◽  
Systematic Investigation ◽  
Stopping Power ◽  
Rare Gases ◽  
Scintillation Method ◽  
Α Particles

In a recent paper R. H. Fowler (1) has calculated the atomic stopping powers of various substances for α-rays on the basis of Henderson’s (2) theory of the loss of energy of an α-ray in passing through matter, and has drawn attention to the desirability of a systematic investigation of the range of α-rays in different media. In particular, the considerable discrepancy between experiment and theory in the case of helium made it desirable to carry out further measurements with this gas for the purpose of confirmation. Also, it was considered that experiments on the range of α-rays in such comparatively simple substances as the rare gases would yield valuable information concerning the relation between the observed values of the stopping power and those calculated by Fowler. The simple monatomic gases have the great advantage, that we are free from the complications of molecular structure and dissociations. The range of the α-particles from polonium was investigated by E. P. Adams (3) for a number of gases by a scintillation method. For convenience, taking the value of the range in air at 15°C. and 760 mm. of mercury to be 3·93 cm., the corresponding values for argon and helium were 4·18 cm. and 13·58 cm. respectively. The ranges of the α-rays from polonium and radium C in helium were found by Taylor (4) to be 17·62 cm. and 32·54 cm. respectively. It will be seen that the results of Adams and Taylor for helium are very different. The preceding values for helium and argon seem to be the only data available in the case of the rare gases.

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