MCNPX-CINDER'90 Simulation of Photonuclear Mo-99 Production Experiments

Conference · Sat Jan 01 04:00:00 EST 2011

OSTI ID:1012630

Kelsey, IV, Charles T ^[1]; Chemerizov, Sergey D ^[2]; Dale, Gregory E ^[1]; Harvey, James T ^[3]; Tkac, Peter ^[2]; Vandegrift, George R III ^[2]

---

1. Los Alamos National Laboratory
2. Argonne National Laboratory
3. NorthStar Medical Radioisotopes

The MCNPX and CINDER'90 codes were used to support design of experiments investigating Mo-99 production with a 20-MeV electron beam. Bremsstrahlung photons produced by the electron beam interacting with the target drive the desired Mo-100({gamma},n)Mo-99 reaction, as well as many undesired reactions important to accurate prediction of radiation hazards. MCNPX is a radiation transport code and CINDER'90 is a transmutation code. They are routinely used together for accelerator activation calculations. Low energy neutron fluxes and production rates for nonneutron and high energy neutron induced reactions computed using MCNPX are inputs to CINDER'90. CINDER'90 presently has only a neutron reaction cross section library up to 25 MeV and normally the other reaction rates come from MCNPX physics models. For this work MCNPX photon flux tallies modified by energy response functions prepared from evaluated photonuclear cross section data were used to tally the reaction rates for CINDER'90 input. The cross section evaluations do not provide isomer to ground state yield ratios so a spin based approximation was used. Post irradiation dose rates were calculated using MCNPX with CINDER'90 produced decay photon spectra. The sensitivity of radionuclide activities and dose rates to beam parameters including energy, position, and profile, as well as underlying isomer assumptions, was investigated. Three experimental production targets were irradiated, two natural Mo and one Mo-100 enriched. Natural Mo foils upstream of the targets were used to analyze beam position and profile by exposing Gafchromic film to the foils after each irradiation. Activation and dose rate calculations were rerun after the experiments using measured beam parameters for comparison with measured Mo-99 activities and dose rates.

• Research Organization: Los Alamos National Laboratory (LANL)
• Sponsoring Organization: DOE/LANL
• DOE Contract Number: AC52-06NA25396
• OSTI ID: 1012630
• Report Number(s): LA-UR-11-10487
• Country of Publication: United States
• Language: English

Related Subjects

Accelerator Design, Technology, and Operations
BEAM POSITION
BREMSSTRAHLUNG
CROSS SECTIONS
DOSE RATES
ELECTRON BEAMS
Engineering (42)
GROUND STATES
IRRADIATION
ISOMERS
Isotope & Radiation Sources (07)
NEUTRON REACTIONS
NEUTRONS
Nuclear Physics & Radiation Physics (73)
PHOTONS
Particle Accelerators (43)
RADIATION HAZARDS
RADIATION TRANSPORT
RADIOISOTOPES
REACTION KINETICS
RESPONSE FUNCTIONS
Radiology & Nuclear Medicine (62)
SPECTRA
SPIN
TARGETS
TRANSMUTATION