Oxygen enhancement ratio for d(800) + (Be + Ta) and d(800) + (Ta + Be) neutrons
Specialized experiments were performed to determine whether the neutron oxygen enhancement ratio (OER) changes significantly as the mean energy increases above 25 MeV. The experimental design called for OER measurements at two energies in the same experiment. The neutron production reaction d(80) + (Be + Ta) generated a beam with mean energy 38 MeV; upon rotation of the target, d(80) + (Ta + Be) neutrons were generated with mean energy 25 MeV. Suspensions of the bacterium Serratia marcesens were irradiated in oxic-hypoxic pairs, alternately with high- and lower-energy neutrons. Replicate experiments yielded OER values and 95% confidence limits of 2.25 (2.05, 2.50) at 25 MeV and 1.67 (1.57, 1.79) at 38 MeV. The x-ray OER was 3.3 (3.1, 3.5). The significant decrease in OER supports our results with Vicia faba showing OER values of 1.7, 1.4, and 2.6 for 25- and 38-MeV neutrons and for x rays, respectively. The yield of spallation products with mass number 6, 7, 9, 10, and 11 arising from neutrons interacting in tissue was analyzed. The tissue kerma from such product contribute kerma equal to 15 to 30% of the recoil proton kerma and thus may provide the physical basis for the observed OER reduction at high neutron energies.
- Research Organization:
- Univ. of Maryland, Baltimore
- OSTI ID:
- 5025301
- Journal Information:
- Radiat. Res.; (United States), Vol. 83:1
- Country of Publication:
- United States
- Language:
- English
Similar Records
Oxygen enhancement ratio as a function of neutron energy with mammalian cells in culture
RBE of d(59)-Be neutrons and of 650-MeV helium ions at different depths for growth reduction in Vivia faba
Related Subjects
FAST NEUTRONS
OXYGEN ENHANCEMENT RATIO
SERRATIA
BIOLOGICAL RADIATION EFFECTS
VICIA
ANOXIA
COMPARATIVE EVALUATIONS
GROWTH
KERMA
MEV RANGE 10-100
NEUTRON THERAPY
RADIATION DOSES
SURVIVAL CURVES
X RADIATION
BACTERIA
BARYONS
BIOLOGICAL EFFECTS
DOSES
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
HADRONS
IONIZING RADIATIONS
LEGUMINOSAE
MEDICINE
MEV RANGE
MICROORGANISMS
NEUTRONS
NUCLEAR MEDICINE
NUCLEONS
PLANTS
RADIATION EFFECTS
RADIATIONS
RADIOLOGY
RADIOTHERAPY
THERAPY
560131* - Radiation Effects on Microorganisms- Basic Studies- (-1987)
560141 - Radiation Effects on Plants- Basic Studies- (-1987)