| 1. |
- Ashrafi, S., et al.
(författare)
-
Monte-Carlo simulation of the charged particle detector used in the NORDBALL gamma-ray spectrometer
- 2001
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - 0168-9002 .- 1872-9576. ; 458:3, s. 690-697
-
Tidskriftsartikel (refereegranskat)abstract
- The NORDBALL silicon detector array for detecting light charged particles emitted in fusion evaporation reactions was simulated with the Monte-Carlo method. The data from the reaction of 261 MeV Ni-58 ions with Cr-50 nuclei in a 4.8 mg/cm(2) thick target was used to adjust the simulation parameters. Relative population of residual nuclei in the reaction was determined, by comparing the intensities of gamma -rays.
|
|
| 2. |
- Jonsson, S., et al.
(författare)
-
Experimental validation of corrections factors for gamma-gamma and gamma-X coincidence summing of Ba-133, Eu-152, and Sb-125 in volume sources
- 2020
-
Ingår i: Journal of Radioanalytical and Nuclear Chemistry. - : Springer Science and Business Media LLC. - 0236-5731 .- 1588-2780. ; 323:1, s. 465-472
-
Tidskriftsartikel (refereegranskat)abstract
- True coincidence summing correction factors for Ba-133, Eu-152 and Sb-125 were determined experimentally for a small volume source and compared with correction factors obtained with three softwares (EFFTRAN-X, GESPECOR and VGSL). The radionuclides investigated have a relatively challenging decay scheme and their spectra are known to suffer from losses due to summation (gamma-gamma, gamma-X and X-X) when measured at close distances on a HPGe detector sensitive to low energy photons. This study shows that the softwares were in good agreement with each other and the experimental data and the calculated activity was consistent with the activity in the volume source.
|
|
| 3. |
- Jonsson, S., et al.
(författare)
-
Implementation of calculation codes in gamma spectrometry measurements for corrections of systematic effects
- 2015
-
Ingår i: Journal of Radioanalytical and Nuclear Chemistry. - : Springer Science and Business Media LLC. - 0236-5731 .- 1588-2780. ; 303:3, s. 1727-1736
-
Tidskriftsartikel (refereegranskat)abstract
- Four calculation codes were implemented on experimental data to calculate corrections of common systematic effects within high resolution gamma spectrometry. The detector parameters were sparsely optimized to imitate the usage that can be expected from personnel with limited experience. The transfer of the efficiency from the calibration geometry (60 ml, density 1.0 g/cm(3)) to 200 ml geometry (density 1.5 g/cm(3)) failed with all codes, which was discouraging. However, a majority of the other corrected activities deviated with less than 10 % from the reference activity values, even for density corrections or when corrections had been calculated for new source-detector-geometries. Smaller deviations, around 5 % or less, were achieved when corrections were done within the calibrated geometry. This shows a robustness of the calculation codes even if the in-data is not perfectly optimized.
|
|
| 4. |
- Ramebäck, Henrik, 1967, et al.
(författare)
-
A laboratory exercise on systematic effects in gamma ray spectrometry
- 2015
-
Ingår i: Journal of Radioanalytical and Nuclear Chemistry. - : Springer Science and Business Media LLC. - 0236-5731 .- 1588-2780. ; 304:1, s. 467-471
-
Tidskriftsartikel (refereegranskat)abstract
- A laboratory exercise for calculation of true coincidence summing correction factors as well as calculating the effect of deviations between sample and standard source (filling height) was developed. This laboratory exercise was held in a masters course in nuclear chemistry the first time during fall 2013. The aim of the exercise was to high-light the importance of correcting for biases due to different systematic effects in gamma spectrometric measurements.
|
|
| 5. |
- Ramebäck, Henrik, 1967, et al.
(författare)
-
Gamma spectrometric measurement of uranium isotopic composition and mass in sintered UO 2 pellets using the efficiency transfer method
- 2023
-
Ingår i: Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine. - : Elsevier BV. - 0969-8043 .- 1872-9800. ; 192, s. 110607-
-
Tidskriftsartikel (refereegranskat)abstract
- Gamma spectrometric measurements to determine the isotopic composition and total uranium mass in UO2 pellets (D = 7.5 mm; H = 3.5 mm, ρ = 10 g/cm3) were carried out. The required efficiency curve was obtained by applying the efficiency transfer method from a calibration standard (D = 65 mm; H = 20 mm) of a slightly acidified water solution. The average isotopic composition of ten UO2 pellets was consistent with values of natural uranium given by IUPAC. The average relative bias for the 235U/238U amount ratio was -0.73% using the 1001 keV gamma line for 238U and 0.50% using the 63 keV gamma line (186 keV was always used for 235U). For the total uranium mass, the mean deviation as compared to mass determinations using a balance was 5.5% using the 1001 keV gamma line for 238U and 4.3% using the 63 keV gamma line.
|
|
| 6. |
- Ramebäck, Henrik, 1967, et al.
(författare)
-
On the accuracy of gamma spectrometric isotope ratio measurements of uranium
- 2016
-
Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 815, s. 57-61
-
Tidskriftsartikel (refereegranskat)abstract
- The isotopic composition of uranium was measured using high resolution gamma spectrometry. Two acid solutions and two samples in the form of UO2 pellets were measured. The measurements were done in close geometries, i.e. directly on the endcap of the high purity germanium detector (HPGe). Applying no corrections for count losses due to true coincidence summing (TCS) resulted in up to about 40% deviation in the abundance of U-235 from the results obtained with mass spectrometry. However, after correction for TCS, excellent agreement was achieved between the results obtained using two different measurement methods, or a certified value. Moreover, after corrections, the fitted relative response curves correlated excellently with simulated responses, for the different geometries, of the HPGe detector.
|
|
| 7. |
- Vidmar, T., et al.
(författare)
-
Equivalence of computer codes for calculation of coincidence summing correction factors - Part II
- 2016
-
Ingår i: Applied Radiation and Isotopes. - : Elsevier BV. - 0969-8043 .- 1872-9800. ; 109, s. 482-486
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to check for equivalence of computer codes that are capable of performing calculations of true coincidence summing (TCS) correction factors. All calculations were performed for a set of well-defined detector parameters, sample parameters and decay scheme data. The studied geometry was a point source of Ba-133 positioned directly on the detector window of a low-energy (n-type) detector. Good agreement was established between the TCS correction factors computed by the different codes.
|
|
