Shielding measurements for a 230 MeV proton beam

Technical Report · Mon Jan 01 00:00:00 EST 1990

DOI:https://doi.org/10.2172/6504628· OSTI ID:6504628

Siebers, J V

Energetic secondary neutrons produced as protons interact with accelerator components and patients dominate the radiation shielding environment for proton radiotherapy facilities. Due to the scarcity of data describing neutron production, attenuation, absorbed dose, and dose equivalent values, these parameters were measured for 230 MeV proton bombardment of stopping length Al, Fe, and Pb targets at emission angles of 0{degree}, 22{degree}, 45{degree}, and 90{degree} in a thick concrete shield. Low pressure tissue-equivalent proportional counters with volumes ranging from 1 cm{sup 3} to 1000 cm{sup 3} were used to obtain microdosimetric spectra from which absorbed dose and radiation quality are deduced. Does equivalent values and attenuation lengths determined at depth in the shield were found to vary sharply with angle, but were found to be independent of target material. Neutron dose and radiation length values are compared with Monte Carlo neutron transport calculations performed using the Los Alamos High Energy Transport Code (LAHET). Calculations used 230 MeV protons incident upon an Fe target in a shielding geometry similar to that used in the experiment. LAHET calculations overestimated measured attenuation values at 0{degree}, 22{degree}, and 45{degree}, yet correctly predicted the attenuation length at 90{degree}. Comparison of the mean radiation quality estimated with the Monte Carlo calculations with measurements suggest that neutron quality factors should be increased by a factor of 1.4. These results are useful for the shielding design of new facilities as well as for testing neutron production and transport calculations.

• Research Organization: Wisconsin Univ., Madison, WI (USA). Dept. of Medical Physics
• Sponsoring Organization: DOE/ER
• DOE Contract Number: FG02-86ER60417
• OSTI ID: 6504628
• Report Number(s): DOE/ER/60417-3; ON: DE91001774; TRN: 90-035775
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
43 PARTICLE ACCELERATORS
61 RADIATION PROTECTION AND DOSIMETRY
ACCELERATORS
SHIELDING
PROTON BEAMS
RADIATION HAZARDS
RADIATION DETECTION
ALUMINIUM
BEAM MONITORING
BRAGG GRAY CHAMBERS
EXPERIMENTAL DATA
IRON
LEAD
MONTE CARLO METHOD
NEUTRON FLUENCE
NEUTRON TRANSPORT
PROGRESS REPORT
PROPORTIONAL COUNTERS
BEAMS
DATA
DETECTION
DOCUMENT TYPES
DOSEMETERS
ELEMENTS
HAZARDS
HEALTH HAZARDS
INFORMATION
IONIZATION CHAMBERS
MEASURING INSTRUMENTS
METALS
MONITORING
NEUTRAL-PARTICLE TRANSPORT
NUCLEON BEAMS
NUMERICAL DATA
PARTICLE BEAMS
RADIATION DETECTORS
RADIATION TRANSPORT
TRANSITION ELEMENTS
654001* - Radiation & Shielding Physics- Radiation Physics
Shielding Calculations & Experiments
430303 - Particle Accelerators- Experimental Facilities & Equipment
655003 - Medical Physics- Dosimetry