Bremsstrahlung Attenuation Measurements in Ilmenite Loaded Concretes

Lokan, K.H.; Sherman, N. K.; Gellie, R.W.; Henry, W H; Levesque, Roch; Nowak, A. V.; Teather, George G.; Lundquist, J.R.

doi:10.1097/00004032-197208000-00009

Cited by 4 publications

(4 citation statements)

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“…Comparison of the measured TVL data with published data for other high-density concretes has proved interesting, with the materials displaying similar attenuation properties. Attenuation of 10 MV photons in ilmenite-loaded concrete at a density of 240 lb ft Ϫ3 (approx 3.8 g cm Ϫ3 ), as investigated by Lokan et al (1972) yields attenuation graphs giving an approximate TVL of 229 mm. Similarly, attenuation of 6 and 10 MV photons in heavy concrete (density 3.31 g cm Ϫ3 ), as investigated by Maruyama et al (1971), yield TVL values of 225 and 255 mm, respectively.…”

Section: Discussionmentioning

confidence: 99%

“…No data have been published on the attenuation properties of this material although some papers have measured the attenuation properties of other high density concretes. These include works by Maruyama et al (1971), Lokan et al (1972), Numark and Kase (1985), and Barish (1993). The attenuation of leakage neutron and photon radiation by a range of ordinary and heavy concretes has also been investigated by Kase et al (2003).…”

Section: Introductionmentioning

confidence: 99%

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ATTENUATION CHARACTERISTICS OF MagnaDense HIGH-DENSITY CONCRETE AT 6, 10 AND 15 MV FOR USE IN RADIOTHERAPY BUNKER DESIGN

Jones

Peet²,

Horton³

2009

Health Physics

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The attenuation characteristics of MagnaDense high-density concrete are measured using the x-ray beams from two Varian linear accelerators at nominal 6, 10, and 15 megavolt energies. The tenth value layers for the primary beam are evaluated under broad- and narrow-beam conditions. The attenuation of secondary radiation is also investigated. Measured data are compared with existing data used in radiotherapy bunker design, derived from the scaling of published tenth value layers for ordinary concrete according to physical density. Instantaneous dose rates around an existing bunker with MagnaDense concrete walls and a conventional concrete roof are predicted using the various different data and compared to actual dose-rate measurements. Primary beam tenth value layer values derived from the broad-beam measurements are found to represent the attenuation properties of the MagnaDense more accurately than those produced by density-based scaling or from narrow-beam measurements.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

ATTENUATION CHARACTERISTICS OF MagnaDense HIGH-DENSITY CONCRETE AT 6, 10 AND 15 MV FOR USE IN RADIOTHERAPY BUNKER DESIGN

Jones

Peet²,

Horton³

2009

Health Physics

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“…Nelson and LaRiviere (1984) calculated 78 g cm -2 and 64 g cm -2 for the first and second ρTVL respectively at 6 MV. Maruyama, et al (1971), Lokan, et al (1972) and Barish (1993) have published the results of measurements of primary photon transmission through various high-density concretes. Those results are not directly comparable with the measurements of leakage radiation reported here.…”

Section: Photonsmentioning

confidence: 99%

“…However, these data are normally for ordinary concrete and given for primary photons and neutrons, not for leakage photons and neutrons. Maruyama, et al (1971), Lokan, et al (1972) and Barish (1993) have published primary photon transmission data for specific high-density concretes.…”

Section: Introductionmentioning

confidence: 99%

Measurements of Accelerator-Produced Leakage Neutron and Photon Transmission through Concrete

Nelson¹

2002

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Optimum shielding of the radiation from particle accelerators requires knowledge of the attenuation characteristics of the shielding material. The most common material for shielding this radiation is concrete, which can be made using various materials of different densities as aggregates. These different concrete mixes can have very different attenuation characteristics. Information about the attenuation of leakage photons and neutrons in ordinary and heavy concrete is, however, very limited. To increase our knowledge and understanding of the radiation attenuation in concrete of various compositions, we have performed measurements of the transmission of leakage radiation, photons and neutrons, from a Varian Clinac 2100C medical linear accelerator operating at maximum electron energies of 6 and 18 MeV. We have also calculated, using Monte Carlo techniques, the leakage neutron spectra and its transmission through concrete. The results of these measurements and calculations extend the information currently available for designing shielding for medical electron accelerators. Photon transmission characteristics depend more on the manufacturer of the concrete than on the atomic composition. A possible cause for this effect is a non-uniform distribution of the highdensity aggregate, typically iron, in the concrete matrix. Errors in estimated transmission of photons can exceed a factor of three, depending on barrier thickness, if attenuation in high-density concrete is simply scaled from that of normal density concrete. We found that neutron transmission through the high-density concretes can be estimated most reasonably and conservatively by using the linear tenth-value layer of normal concrete if specific values of the tenth-value layer of the high-density concrete are not known. The reason for this is that the neutron transmission depends primarily on the hydrogen content 3 of the concrete, which does not significantly depend on concrete density. Errors of factors of two to more than ten, depending on barrier thickness, in the estimated transmission of neutrons through high-density concrete can be made if the attenuation is scaled by density from normal concrete.

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Measurements of Accelerator-Produced Leakage Neutron and Photon Transmission Through Concrete

et al. 2003

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Optimum shielding of the radiation from particle accelerators requires knowledge of the attenuation characteristics of the shielding material. The most common material for shielding this radiation is concrete, which can be made using various materials of different densities as aggregates. These different concrete mixes can have very different attenuation characteristics. Information about the attenuation of leakage photons and neutrons in ordinary and heavy concrete is, however, very limited. To increase our knowledge and understanding of the radiation attenuation in concrete of various compositions, we have performed measurements of the transmission of leakage radiation, photons and neutrons, from a Varian Clinac 2100C medical linear accelerator operating at maximum electron energies of 6 and 18 MeV. We have also calculated, using Monte Carlo techniques, the leakage neutron spectra and its transmission through concrete. The results of these measurements and calculations extend the information currently available for designing shielding for medical electron accelerators. Photon transmission characteristics depend more on the manufacturer of the concrete than on the atomic composition. A possible cause for this effect is a non-uniform distribution of the high-density aggregate, typically iron, in the concrete matrix. Errors in estimated transmission of photons can exceed a factor of three, depending on barrier thickness, if attenuation in high-density concrete is simply scaled from that of normal density concrete. We found that neutron transmission through the high-density concretes can be estimated most reasonably and conservatively by using the linear tenth-value layer of normal concrete if specific values of the tenth-value layer of the high-density concrete are not known. The reason for this is that the neutron transmission depends primarily on the hydrogen content of the concrete, which does not significantly depend on concrete density. Errors of factors of two to more than ten, depending on barrier thickness, in the estimated transmission of neutrons through high-density concrete can be made if the attenuation is scaled by density from normal concrete.

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Bremsstrahlung Attenuation Measurements in Ilmenite Loaded Concretes

Cited by 4 publications

References 0 publications

ATTENUATION CHARACTERISTICS OF MagnaDense HIGH-DENSITY CONCRETE AT 6, 10 AND 15 MV FOR USE IN RADIOTHERAPY BUNKER DESIGN

ATTENUATION CHARACTERISTICS OF MagnaDense HIGH-DENSITY CONCRETE AT 6, 10 AND 15 MV FOR USE IN RADIOTHERAPY BUNKER DESIGN

Measurements of Accelerator-Produced Leakage Neutron and Photon Transmission through Concrete

Measurements of Accelerator-Produced Leakage Neutron and Photon Transmission Through Concrete

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