+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Characteristics of proton beam scanning dependent on Li target thickness from the viewpoint of heat removal and material strength for accelerator-based BNCT



Characteristics of proton beam scanning dependent on Li target thickness from the viewpoint of heat removal and material strength for accelerator-based BNCT



Applied Radiation and Isotopes 67(2): 259-265



This study demonstrates the characterization of proton spot scanning on a Li target assembly for accelerator-based BNCT from the viewpoint of heat removal and material strength. These characteristics are investigated as to their dependence on the Li target thickness, considering that the Cu backing plate has more suitable heat removal properties than Li. Two situations are considered in this paper, i.e. the cyclic operation of the spot scanning, and a stalled spot scanning cycle where the proton beam stays focused on a single position on the Li target. It was found that the maximum of the Li temperature and the strain of the Cu backing increase as the cycle period increases. A cycle period less than 120 ms (over 8.3 Hz of frequency) enables the Li temperature to be kept below 150 degrees C and a cycle of less than 115 ms (8.7 Hz) keeps the Cu strain below the critical value for a 230 microm thick Li target, though the values are evaluated conservatively. Against expectation, the Li temperature and Cu strain are larger for a 100 microm thick target than for a 230 microm target. The required cycle period in this case is 23 ms (43 Hz) for maintaining a reasonable Li temperature and 9 ms (110 Hz) to prevent Cu fatigue fracture. For a stall in the spot scanning cycle, the Cu temperature increases as the beam shutdown time increases. The time for Cu to reach its melting point is estimated to be 4.2 ms at the surface, 20 ms at 1mm depth, for both of 100 and 230 microm thick targets. At least 34 ms is estimated to be enough to make a hole on Cu backing plate. A beam shutdown mechanism with a response time of about 20 ms is therefore required.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 052024492

Download citation: RISBibTeXText

PMID: 19042135

DOI: 10.1016/j.apradiso.2008.10.002


Related references

Variations in lithium target thickness and proton energy stability for the near-threshold 7Li(p,n)7Be accelerator-based BNCT. Physics in Medicine and Biology 52(3): 645-658, 2007

Characteristics of BDE dependent on 10B concentration for accelerator-based BNCT using near-threshold 7Li(p,n)7Be direct neutrons. Applied Radiation and Isotopes 61(5): 875-879, 2004

What is the best proton energy for accelerator-based BNCT using the 7Li(p,n)7Be reaction?. Medical Physics 27(5): 1113-1118, 2000

Beam shaping assembly optimization for (7)Li(p,n)(7)Be accelerator based BNCT. Applied Radiation and Isotopes 88: 233-237, 2014

A design study for an accelerator-based epithermal neutron beam for BNCT. Physics In Medicine & Biology. 40(5): 807-821, 1995

An optimized neutron-beam shaping assembly for accelerator-based BNCT. Applied Radiation and Isotopes 61(5): 811-815, 2004

Design of thermal neutron beam based on an electron linear accelerator for BNCT. Applied Radiation and Isotopes 118: 149-153, 2016

Optimization of the photoneutron target geometry for e-accelerator based BNCT. Electronic Physician 9(6): 4590-4596, 2017

Proton pencil beam scanning for mediastinal lymphoma: the impact of interplay between target motion and beam scanning. Physics in Medicine and Biology 60(7): 3013-3029, 2015

Treatment planning capability assessment of a beam shaping assembly for accelerator-based BNCT. Applied Radiation and Isotopes 69(12): 1870-1873, 2011

Be target development for the accelerator-based SPES-BNCT facility at INFN Legnaro. Applied Radiation and Isotopes 67(7-8 Suppl): S270-S273, 2009

An accelerator-based epithermal neutron beam design for BNCT and dosimetric evaluation using a voxel head phantom. Radiation Protection Dosimetry 110(1-4): 655-660, 2004

Design of a beam shaping assembly and preliminary modelling of a treatment room for accelerator-based BNCT at CNEA. Applied Radiation and Isotopes 69(12): 1688-1691, 2011

A practical target system for accelerator-based BNCT which may effectively double the dose rate. Medical Physics 25(6): 894-896, 1998

Design of photon converter and photoneutron target for High power electron accelerator based BNCT. Applied Radiation and Isotopes 106: 45-48, 2015