title: High-power electron beam tests of a liquid-lithium target and characterization study of (7)Li(p,n) near-threshold neutrons for accelerator-based boron neutron capture therapy.
abstract: A compact Liquid-Lithium Target (LiLiT) was built and tested with a high-power electron gun at Soreq Nuclear Research Center (SNRC). The target is intended to demonstrate liquid-lithium target capabilities to constitute an accelerator-based intense neutron source for Boron Neutron Capture Therapy (BNCT) in hospitals. The lithium target will produce neutrons through the (7)Li(p,n)(7)Be reaction and it will overcome the major problem of removing the thermal power >5kW generated by high-intensity proton beams, necessary for sufficient therapeutic neutron flux. In preliminary experiments liquid lithium was flown through the target loop and generated a stable jet on the concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power densities of more than 4kW/cm(2) and volumetric power density around 2MW/cm(3) at a lithium flow of ~4m/s, while maintaining stable temperature and vacuum conditions. These power densities correspond to a narrow (σ=~2mm) 1.91MeV, 3mA proton beam. A high-intensity proton beam irradiation (1.91-2.5MeV, 2mA) is being commissioned at the SARAF (Soreq Applied Research Accelerator Facility) superconducting linear accelerator. In order to determine the conditions of LiLiT proton irradiation for BNCT and to tailor the neutron energy spectrum, a characterization of near threshold (~1.91MeV) (7)Li(p,n) neutrons is in progress based on Monte-Carlo (MCNP and Geant4) simulation and on low-intensity experiments with solid LiF targets. In-phantom dosimetry measurements are performed using special designed dosimeters based on CR-39 track detectors.
authors.affiliation: Soreq NRC, Yavne 81800, Israel; Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel. Electronic address: halfon@phys.huji.ac.il.
authors.forename: S
authors.initials: S
authors.lastname: Halfon
authors.affiliation: Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel.
authors.forename: M
authors.initials: M
authors.lastname: Paul
authors.affiliation: Soreq NRC, Yavne 81800, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Arenshtam
authors.affiliation: Soreq NRC, Yavne 81800, Israel.
authors.forename: D
authors.initials: D
authors.lastname: Berkovits
authors.affiliation: Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel.
authors.forename: D
authors.initials: D
authors.lastname: Cohen
authors.affiliation: Soreq NRC, Yavne 81800, Israel.
authors.forename: I
authors.initials: I
authors.lastname: Eliyahu
authors.affiliation: Soreq NRC, Yavne 81800, Israel.
authors.forename: D
authors.initials: D
authors.lastname: Kijel
authors.affiliation: Soreq NRC, Yavne 81800, Israel.
authors.forename: I
authors.initials: I
authors.lastname: Mardor
authors.affiliation: Soreq NRC, Yavne 81800, Israel.
authors.forename: I
authors.initials: I
authors.lastname: Silverman
mesh_terms: D016754:Boron Neutron Capture Therapy / Q000295:instrumentation*; D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007554:Isotopes / Q000737:chemistry / Q000528:radiation effects; D008094:Lithium / Q000737:chemistry / Q000528:radiation effects*; D015233:Models, Statistical; D009502:Neutrons; D010315:Particle Accelerators / Q000295:instrumentation*; D011874:Radiometry; D011879:Radiotherapy Dosage; D011882:Radiotherapy, High-Energy / Q000295:instrumentation* / Q000379:methods; D012542:Scattering, Radiation; D012996:Solutions
chemical_list: D007554:Isotopes; D012996:Solutions; D008094:Lithium
keywords: Accelerator-based BNCT; Liquid-lithium; Target