The Characteristics of a High Intensity 24 keV Iron-Filtered Neutron Beam

Perks, C.A.; Harrison, K.G.; Birch, Rolf B.; Delafield, H.J.

doi:10.1093/oxfordjournals.rpd.a079673

Cited by 12 publications

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“…The 24 keV neutrons were obtained by filtering neutrons from a research reactor (PLUTO, located at AEA Technology's Harwell Laboratory) with a filter of iron, aluminium and sulphur [14][15][16]. Although of interest for BNCT, the relative biological effectiveness (rbe) of this beam for cell killing in non-boronated tissue was found to be relatively high, a possible disadvantage for therapy because of the potential for significant damage to normal surface tissues.…”

mentioning

confidence: 99%

Cell survival measurements in an argon, aluminium and sulphur filtered neutron beam: a comparison with 24 keV neutrons and relevance to boron neutron capture therapy

Mill¹,

Morgan²,

Newman³

1994

The British Journal of Radiology

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Boron neutron capture therapy (BNCT) has been advanced as a suitable alternative therapy for the treatment of glioma. BNCT involves the selective uptake of a tumour with a boron-bearing substance and subsequent irradiation with a beam of neutrons. Previous attempts with BNCT have utilized thermal neutrons, but this involves resection of the scalp prior to treatment and is only possible with superficial tumours. An alternative is to use a beam of intermediate-energy neutrons which will produce a peak in the thermal neutron fluence at depth in tissue and so enable deep-seated tumours to be treated. A neutron beam with a mean energy of approximately 9 keV, obtained by filtering neutrons from a reactor with aluminium, argon and sulphur, has been used to explore the radiobiological advantage over thermal and 24 keV neutrons for BNCT. Irradiation of V79 and HeLa cells at various positions in a polythene phantom suggest that the beam is less cytotoxic for a given neutron fluence than the 24 keV neutron beam previously considered as an alternative to thermal neutrons for BNCT. However, optimization of boron distribution via the development of new compounds still appears to be necessary for BNCT to become a safe alternative option for the treatment of glioma.

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confidence: 99%

Cell survival measurements in an argon, aluminium and sulphur filtered neutron beam: a comparison with 24 keV neutrons and relevance to boron neutron capture therapy

Mill¹,

Morgan²,

Newman³

1994

The British Journal of Radiology

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“…Well-calibrated, moderated neutron fields, including specification of a moderated 252Cf spectrum that more closely simulates power reactor containment spectra, are now available (Griffith et al 1978a;ANSI 1983;Sims 1986). Development of monoenergetic neutron fields contribute to our understanding of instrument response (Schwartz and Eisenhauer 1977;Perks et al 1986). The considerations involved in the calibration process are well understood (Eisenhauer et al 1986).…”

Section: Calibrationsmentioning

confidence: 99%

The Next Decade in External Dosimetry

Griffith¹

1988

Health Physics

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In recent years, a number of external dosimetry problems have been solved. However, changes in standards and legal concepts relating to the application of dosimetry results will require further enhancements in measurement techniques and philosophy in the next 10 y. The introduction of effective dose equivalent and the legal use of probability of causation will require that much greater attention be given to determination of weighted organ dose from external exposure. An imminent change--an increase in the fast neutron quality factor--will require a new round of technology development in a field that has just received a decade of close scrutiny. For the future, we must take advantage of developments in microelectronics. The use of random access memory (RAM) and metal-on-silicon (MOS) devices as detector elements, particularly for neutron dosimetry, has exciting possibilities that are just beginning to be explored. Advances in microcircuitry are leading, and will continue to lead, in the development of a new generation of small, rugged and "smart" radiation survey instruments that will make the most of detector data. It has become possible with very compact instruments to obtain energy spectra, linear-energy-transfer (LET) spectra, and quality factors in addition to the usual integrated dosimetric quantities: exposure, absorbed dose, and dose equivalent. These instruments will be reliable and easy to use. The user will be able to select the level of sophistication that is required for any specific application. Moreover, since the processing algorithms can be changed, changes in conversion factors can be accommodated with relative ease. During the next decade, the use of computers will continue to grow in value to the health physicist. Personal computers and codes designed for dosimetry applications will become prominent, providing the health physicist with the ability to perform sophisticated data reduction, spectra unfolding and even radiation modeling and transport calculations on the desk top. In the far term, the use of computers could extend to the development of sophisticated tracking systems that would follow and record the workers' movements throughout a radiation area. These data, together with information from area monitors, air samplers and personnel dosimeters, could be used to develop truly integrated dose estimates, including reconstruction of organ doses.

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“…These materials have ''resonance windows'' in their cross-sections, so that neutrons with energies corresponding to these windows are transmitted, whilst neutrons with other energies are attenuated. Several references regarding the application of passive monochromators can be found in literature [1,2].…”

Section: Introductionmentioning

confidence: 99%

Optimization of filtered neutron beams for the calibration of superheated droplet detectors at the RPI

Nascimento

Ramos

Fernandes

et al. 2007

Nuclear Instruments and Methods in Physics Research Section A:

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Superheated droplet detectors (SDDs) have been investigated for applications in neutron dosimetry and spectrometry. Varying the detector temperature, it is possible to change the neutron energy detection threshold of SDDs, thus allowing the use of a single detector to measure neutrons of different energy, without any change of the experimental setup. However, the neutron threshold energy versus temperature curves have to be experimentally determined. The determination of the calibration curves requires the use of monochromatic neutron beams.The neutron spectrum from a nuclear reactor covers a wide energy range, from meV to several MeV. Beams of quasi-monochromatic neutrons can be generated by filtering neutrons emerging from the core with suitable materials, such as Fe (for 24 keV neutrons) and Si (144 and 54 keV). These materials have windows in their neutron cross-sections, so that neutrons corresponding to these windows are transmitted, whereas neutrons with other energies are attenuated.We report on the MCNP simulation study of passive monochromators of Si þ S and Si þ Ti for the production of quasimonochromatic neutron beams of 54 keV ðSi þ SÞ and 144 keV ðSi þ TiÞ. The simulations allowed the purity versus intensity of the neutron beams to be optimized, within the geometrical constraints of the beam port. r

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The Characteristics of a High Intensity 24 keV Iron-Filtered Neutron Beam

Cited by 12 publications

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Cell survival measurements in an argon, aluminium and sulphur filtered neutron beam: a comparison with 24 keV neutrons and relevance to boron neutron capture therapy

Cell survival measurements in an argon, aluminium and sulphur filtered neutron beam: a comparison with 24 keV neutrons and relevance to boron neutron capture therapy

The Next Decade in External Dosimetry

Optimization of filtered neutron beams for the calibration of superheated droplet detectors at the RPI

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