Determination of Energy Deposited in Nanometre Sites from Ionisation Data

Bigildeev, E. A.; Lappa, Alexander V.

doi:10.1093/oxfordjournals.rpd.a082164

Cited by 6 publications

(10 citation statements)

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“…(The corrections due to the geometry of the target discussed in this paper did not affect the critical volume reported by Lindborg et al) If the dose-mean lineal energy values are derived from single-event probability distributions of the number of ionizations and a constant W/e, the ratios are expected to be very similar to ȳD -ratios derived from single-event dose distributions for spheres with diameters larger than 10 nm, Table 2. 31 This observation deserves further attention.…”

Section: Discussionmentioning

confidence: 86%

“…These numbers were converted by Olko to frequency‐ and dose‐mean lineal energy values by multiplying with a constant W / e = 30 eV/ion pair 14 . A volume dependent correction factor of W / e published by Bigildeev and Lappa 31 (Table 2) was applied to the TRION values (denoted TRION corr below). The correction will change a

{\bar{y}_{\rm{D}}}

‐value based on number of ionizations and a constant value of W / e to a

{\bar{y}_{\rm{D}}}

‐value based on energy imparted.…”

Section: Methodsmentioning

confidence: 99%

“…With gas‐filled detectors the number of ionizations is measured which after multiplication with the mean energy expended to create an ion pair, W / e , represents the mean energy imparted from ionizations and excitations in the sensitive volume of the detector. However, W / e is energy and particle dependent, and it has been argued that for a small number of ionizations the use of a nonstochastic quantity like W / e becomes invalid 31 . Ionization measurements will therefore, unless corrected for, gradually lose its direct relation to the energy imparted as the volumes become smaller 27 .…”

Section: Introductionmentioning

confidence: 99%

“…However, W/e is energy and particle dependent, and it has been argued that for a small number of ionizations the use of a nonstochastic quantity like W/e becomes invalid. 31 Ionization measurements will therefore, unless corrected for, gradually lose its direct relation to the energy imparted as the volumes become smaller. 27 This is not a problem for calculations where the interaction cross-section uncertainties used as input in the codes and the degree of details considered, are of greater importance.…”

Section: Introductionmentioning

confidence: 99%

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Dose‐mean lineal energy values for electrons by different Monte Carlo codes: Consequences for estimates of radiation quality in photon beams

et al. 2021

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Background:The microdosimetric quantity lineal energy and its mean values have proven useful for quantifying radiation quality in many situations. The ratio of dose-mean lineal energies is perhaps the simplest quantity for quantifying differences between two radiation qualities. However, published dose-mean lineal energy values from different codes may differ significantly with potential influence on radiation quality estimates. Purpose: The purpose was to compare dose-mean lineal energy values from different track-structure data sets for condensed water vapor and liquid water, and to evaluate the influence on radiation quality estimations for some photon sources. Methods: Published dose-mean lineal energy values for 0.1 keV to 1 MeV electrons in spheres with diameters 2 nm to 1 μm, calculated with water vapor and liquid water track structure codes and proximity functions, were collected, analyzed, and compared. Data for cylinders were converted to spheres using a theoretical transformation published by Kellerer. A new set of dose-mean lineal energy values was calculated to cover the whole range of volumes of interest here using the GEANT4-DNA code. The influence from the differences between codes on radiation quality calculations was estimated using dose-mean lineal energy ratios for the photon sources 125 I, 169 Yb, and 192 Ir relative to 60 Co. Results: The theoretical relation for converting the dose-mean lineal energy between different geometrical volumes, results in differences up to 10% between cylinders and spheres depending on electron energy and target size, in agreement with published simulated results. For spheres with diameter above 100 nm, dose-mean lineal energy values for condensed water vapor and liquid water are with few exceptions within ±10%. Below 100 nm, the difference increases with decreasing diameter reaching a factor of two at 2 nm. The values from water vapor codes are in general larger than from liquid water codes. If the dose-mean lineal energy ratio is based on condensed water vapor instead of liquid water, the ratio differs less than 9% for the nuclides 125 I, 169 Yb, and 192 Ir relative to 60 Co independent of the volume simulated. However, a specific value of the dose-mean lineal energy ratio, is found at a larger target diameter in liquid water than in condensed water vapor. Conclusions: When ratios of the dose-mean lineal energy are used as a measure of the radiation quality it is important to compare values for geometrically equal target shapes. A practical method of converting values for cylinders of equal diameter and height to spheres was demonstrated. Although dose-mean lineal energy values calculated with water vapor and liquid water codes may differ significantly, the radiation quality, in terms of ratios of dose-mean lineal 1286

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Section: Discussionmentioning

confidence: 86%

{\bar{y}_{\rm{D}}}

‐value based on number of ionizations and a constant value of W / e to a

{\bar{y}_{\rm{D}}}

‐value based on energy imparted.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dose‐mean lineal energy values for electrons by different Monte Carlo codes: Consequences for estimates of radiation quality in photon beams

et al. 2021

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show abstract

“…Correction factors for both the frequency and dose mean energy imparted for spherical volumes with diameters of less than 100 nm have been calculated. 10 These factors will correct the two mean values when a constant W-value has been used in the measurements. The correction factor k(d) relevant for εD,s was only dependent on the diameter of the spherical simulated volume with k(d) being unity when d was 100 nm or larger and 0.9 at 10 nm.…”

Section: Resultsmentioning

confidence: 99%