Measurements of energy losses, distributions of energy loss and additivity of energy losses for 50 to 150 keV protons in hydrogen and nine hydrocarbon gases. [Dependence on carbon bonding]

Technical Report · Sat May 01 04:00:00 EDT 1976

DOI:https://doi.org/10.2172/7184170· OSTI ID:7184170

Thorngate, J. H.

Measurements of energy-loss distributions were made for 51, 102, and 153 keV protons traversing hydrogen, methane, ethyne (acetylene), ethene (ethylene), ethane, propyne (methyl acetylene), propadiene (allene), propene (propylene), cyclopropane and propane. The objectives were to test the theories of energy-loss distribution in this energy range and to see if the type of carbon bonding in a hydrocarbon molecule affects the shape of the distribution. Stopping powers and stopping cross sections were also measured at these energies and at 76.5 and 127.5 keV to determine effects of chemical binding. All of the measurements were made at the gas density required to give a 4 percent energy loss. The mean energy, second central moment (a measure of the width of the distribution), and the third central moment (a measure of the skew) were calculated from the measured energy-loss distributions. Stopping power values, calculated using the mean energy, compared reasonably well with those calculated from the Bethe stopping power theory. For the second and third central moments, the best agreement between measurement and theory was when the classical scattering probability was used for the calculations, but even these did not agree well. In all cases, variations were found in the data that could be correlated to the type of carbon binding in the molecule. The differences were statistically significant at a 99 percent confidence interval for the stopping powers and second central moments measured with 51 keV protons. Similar trends were noted at other energies and for the third central moment, but the differences were not statistically significant at the 99 percent confidence interval.

• Research Organization: Oak Ridge National Lab., Tenn. (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 7184170
• Report Number(s): ORNL/TM-5165
• Country of Publication: United States
• Language: English

Related Subjects

654001* -- Radiation & Shielding Physics-- Radiation Physics
Shielding Calculations & Experiments
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACETYLENE
ALKANES
ALKENES
ALKYNES
ALLENE
BARYONS
CHARGED-PARTICLE TRANSPORT
CRYOGENIC FLUIDS
DIENES
ELEMENTARY PARTICLES
ELEMENTS
ENERGY LOSSES
ENERGY RANGE
ETHANE
ETHYLENE
FERMIONS
FLUIDS
HADRONS
HYDROCARBONS
HYDROGEN
KEV RANGE
KEV RANGE 10-100
KEV RANGE 100-1000
METHANE
NONMETALS
NUCLEONS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
POLYENES
POLYMERS
POLYOLEFINS
POLYPROPYLENE
PROPANE
PROPYNE
PROTONS
RADIATION TRANSPORT
STOPPING POWER