| 1. |
- Isaksson, M., et al.
(författare)
-
Determination of the retention of 47Ca by whole-body counting
- 2000
-
Ingår i: Applied Radiation and Isotopes. - 0969-8043 .- 1872-9800. ; 52:6, s. 1441-1450
-
Tidskriftsartikel (refereegranskat)abstract
- Retention of intravenously or orally administered 47Ca in the human body are described by a two-parameter function. It is then sufficient to make only a few whole-body measurements to determine the retention function, avoiding faeces sampling and stool markers. Seven days after intake the non-absorbed calcium was excreted and the model agreed with the measured relative retention. Absorption of calcium could then, in some cases (e.g. comparative studies), be described by relative retention at the 7th day after intake. Copyright (C) 2000 Elsevier Science Ltd.
|
|
| 2. |
- Jacobsson, S, et al.
(författare)
-
A tomographic method for experimental verification of the integrity of spent nuclear fuel
- 2000
-
Ingår i: Applied Radiation and Isotopes. - 0969-8043 .- 1872-9800. ; 53:4-5, s. 681-689
-
Tidskriftsartikel (refereegranskat)abstract
- A tomographic method for verification of the integrity of spent nuclear fuel assemblies has been developed. The gamma radiation field emanating from emitted radiation from within the assembly is recorded and utilised for reconstructing the internal source
|
|
| 3. |
- Nilsson, Jonas, 1969-, et al.
(författare)
-
The effects of UV-irradiation on the ESR-dosimetry of tooth enamel
- 2001
-
Ingår i: Applied Radiation and Isotopes. - 0969-8043 .- 1872-9800. ; 54:1, s. 131-139
-
Tidskriftsartikel (refereegranskat)abstract
- Tooth enamel has been shown to be an excellent dosimeter material for retrospective dosimetry. A complication is that it is sensitive to ultraviolet light (UV), creating a signal that interferes with the dosimetric signal. Irradiation of tooth enamel by UV-light induces a mixture of stable and unstable free radicals. The unstable radicals disappear in about three weeks. Stable radicals are created both at the dosimetric peak and at the same g-value as the native peak. The stable peak coinciding with the native peak shows saturation behavior both for UVA/B- and UVC-light. The signal intensity from the sun is roughly estimated to induce a signal comparable to 15 mGy/h from 60 kV X-rays. The blue lamps used by dentists when hardening plastic repairs contain a narrow tail in the UVA/B-region, and it is shown here that these lamps also contribute to the stable peak coincident with the native peak. The contribution to the dosimetry peak, though negligible, at least for the irradiation times is used in this work. Most of the problems with UVA/B-induced signal contributions can probably be avoided by not using front teeth and teeth close to plastic repairs. (C) 2000 Elsevier Science Ltd.Tooth enamel has been shown to be an excellent dosimeter material for retrospective dosimetry. A complication is that it is sensitive to ultraviolet light (UV), creating a signal that interferes with the dosimetric signal. Irradiation of tooth enamel by UV-light induces a mixture of stable and unstable free radicals. The unstable radicals disappear in about three weeks. Stable radicals are created both at the dosimetric peak and at the same g-value as the native peak. The stable peak coinciding with the native peak shows saturation behavior both for UVA/B- and UVC-light. The signal intensity from the sun is roughly estimated to induce a signal comparable to 15 mGy/h from 60 kV X-rays. The blue lamps used by dentists when hardening plastic repairs contain a narrow tail in the UVA/B-region, and it is shown here that these lamps also contribute to the stable peak coincident with the native peak. The contribution to the dosimetry peak, though negligible, at least for the irradiation times is used in this work. Most of the problems with UVA/B-induced signal contributions can probably be avoided by not using front teeth and teeth close to plastic repairs.
|
|
| 4. |
- Olsson, Sara K., 1970-, et al.
(författare)
-
Development of ammonium tartrate as an ESR dosimeter material for clinical purposes
- 2000
-
Ingår i: Applied Radiation and Isotopes. - 0969-8043 .- 1872-9800. ; 52:5, s. 1235-1241
-
Tidskriftsartikel (refereegranskat)abstract
- The crystalline substance ammonium tartrate is investigated with respect to its suitability as a clinical dosimetry material. The properties investigated are: the radical stability for absorbed doses relevant for clinical use, the improvement in sensitivity when the crystals are deuterated and the linear electron tranfer (LET)-dependence. After photon irradiation to an absorbed dose of 20 Gy, the signal increases rapidly during the first 6 h. After this period, the changes are more moderate and can be corrected for. The signal-to-noise ratio of irradiated ammonium tartrate is twice the corresponding value of alanine. By deuterating the crystals, the sensitivity can be further improved by a factor of 1.4. As expected, the signal decreases with increasing LET of the radiation, but no changes in the spectrum shape was observed.
|
|
| 5. |
- Vestad, T.A., et al.
(författare)
-
EPR dosimetric properties of formates
- 2003
-
Ingår i: Applied Radiation and Isotopes. - 0969-8043 .- 1872-9800. ; 59:2-3, s. 181-188
-
Tidskriftsartikel (refereegranskat)abstract
- As a part of a program to develop an electron paramagnetic resonance (EPR) dosimeter suited for clinical use (doses in the cGy range), polycrystalline samples of lithium formate monohydrate (HCO2Li·H 2O), magnesium formate dihydrate (C2H2O 4Mg·2H2O), and calcium formate (C2H 2O4Ca) have been examined. L-Alanine was included for comparison and reference. Samples were irradiated with 60Co ?-rays and 60-220kV X-rays. The dosimeter response was assessed using the peak-to-peak amplitude of the first-derivative EPR spectrum. Dose-response curves for the 60Co ?-irradiated samples were constructed, and the dependences of the response on the photon energy, microwave power, and modulation amplitude were studied. Stability of the irradiation products upon storage (signal fading) was also investigated. Lithium formate monohydrate is by far the best candidate of the tested formates, suitable for measuring doses down to approximately 0.1Gy. Lithium formate monohydrate is more sensitive than alanine by a factor of 5.6-6.8 in the tested photon energy range, it exhibits no zero-dose signal and shows a linear dose response in the dose range from 0.2 to 1000Gy. Its EPR signal was found unchanged in shape and intensity 1 week after irradiation to 10Gy. Various less favorable properties rendered the other formates generally unsuitable, although calcium formate exhibits some interesting EPR dosimetric properties. © 2003 Elsevier Ltd. All rights reserved.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Salih, Isam, et al.
(författare)
-
Impact of fluoride and other aquatic parameters on radon concentration in natural waters
- 2004
-
Ingår i: Journal of Applied Radiation & Isotopes. - : Elsevier BV. - 0969-8043 .- 1872-9800. ; 60:1, s. 99-104
-
Tidskriftsartikel (refereegranskat)abstract
- Radon (222Rn) accumulation in water in relation to stable elements was studied for the purpose of determining factors influencing the transfer of 222Rn to and from water. In 72 groundwater samples, 222Rn and about 70 analytical parameters were analysed using radiometric and ICP-MS techniques. Using multivariate statistics (partial least squares), it was observed that 222Rn has a positive correlation with fluoride and uranium. The correlation with fluoride was further investigated by a laboratory time-scale experiment to measure the emanation of 222Rn from water as a function of fluoride, pH and carbonate. The transfer of 222Rn from water was measured by continuous monitoring in air in a closed loop set-up. It was observed that fluoride in water adhere or trap 222Rn preferably in acidic water (pH 3). It is suspected that natural physical processes (such as diffusion and microbubble phenomenon) are less effective to transport 222Rn in the presence of fluoride.
|
|
| 9. |
- Bäck, Sven, et al.
(författare)
-
Investigation of the NMR relaxation rate dose-response of a ceric sulphate dosimeter
- 2002
-
Ingår i: Applied Radiation and Isotopes. - 0969-8043. ; 56:6, s. 895-899
-
Tidskriftsartikel (refereegranskat)abstract
- The relationship between the radiation absorbed dose and the NMR longitudinal and transversal relaxation rates, R-1 and R-2, respectively, of a ceric sulphate dosimeter was examined. By adding copper sulphate, the R-1 and R-2 dose-responses were found to be linear up to 60 kGy with dose sensitivities of 13 x 10(-6) and 15 x 10(-6) s(-1) Gy-1, respectively. There is thus the potential for a three-dimensional ceric dosimeter for high dose applications. provided a suitable gelling substance is used.
|
|
| 10. |
|
|
