Dosimetry study in an X-ray irradiator : Monte Carlo simulations and experimental results on radio-photoluminescence samples
Matter’s exposure to ionizing radiations leads to a variety of possible interactions.
Depending on the specific interaction type, energy can be deposited into matter via
different mechanisms. The quantification of the absorbed dose in matter is crucial to
monitor the radiation levels and asses radiation effects in matter in different application
areas such as radiation therapy, particle accelerators, space applications, and high-energy nuclear radiation facilities. The stochastic nature of radiation-matter interaction
often requires the use of Monte Carlo tools in dosimetry applications. In the present
work, a commercial X-ray irradiator is modeled using PHITS general Monte Carlo tool,
aiming at verifying the possibility of using it for the irradiation of various types of
macroscopic samples at high doses, ranging between the kGy and the MGy levels.
Simulated particle fluence spectra evidence that the effect of the Be exit window, often
included in the X-ray tube design as a first filter and different additional thicknesses of
Al and Cu filters can be effectively used to attenuate low energy photons, often
responsible for high dose inhomogeneities in thick samples. To assess the feasibility of
using the available X-ray spectra for the irradiation of different samples having
thicknesses up to several millimetres, the absorbed dose across the sample’s depth for
different materials such as Radio Photoluminescent (RPL) glass dosimeters, silica for
comparison purposes and water as reference was calculated using PHITS, with a
sample depth spatial resolution of 0.1 mm and 10 µm. The homogeneity of the absorbed
dose in the RPL dosimeter volume can be improved by the use of appropriate types of
filters and it is found that 1.5 mm, 3 mm thick Al and 1.5 mm thick Cu filters can improve
the dose homogeneity to 30 %, 15 %, and 8 % deviation from the average dose value
respectively in the selected samples. By using a combination of the readout of PTW soft
X-ray ionization chamber, normally used for dose rate calibration in the irradiation
facility, and the realized simulations, the absorbed dose was calculated for 8 RPL glass
samples irradiated in the MOPERIX X-ray irradiator in the frame of another study. The
calculated doses are in good agreement with the corresponding experimental values,
which were measured in the European Organization for Nuclear Research (CERN)
readout systems, allowing a validation of the used methodologies and the estimation of
usable conversion factors.
...
![showless](/themes/JYX2//images/showless.png)
![showmore](/themes/JYX2//images/showmore.png)
Asiasanat
Metadata
Näytä kaikki kuvailutiedotKokoelmat
- Pro gradu -tutkielmat [29015]
Lisenssi
Samankaltainen aineisto
Näytetään aineistoja, joilla on samankaltainen nimeke tai asiasanat.
-
Robustness of radiation beam profile measurements
Nykänen, Topi (2023)In this master’s thesis, profile measurements of PTW Semiflex 3D and PTW Semiflex ionisation chambers in addition to IBA MatriXX matrix detector were compared to each other using different measurement set-ups. The ionisation ... -
Characterization of radio-photo-luminescence (RPL) dosimeters under high dose X-ray irradiation
Hasan, Afrina (2023)Radio-Photo Luminescence (RPL) glasses are used as passive dosimeters, having a wide range of applications in different radiation fields, where low to high doses are absorbed. This work presents an experimental characterisation ... -
Evaluation of radiation stability of electron beam irradiated Nafion® and sulfonated poly(ether ether ketone) membranes
Pajuste, E.; Reinholds, I.; Vaivars, G.; Antuzevičs, A.; Avotiņa, L.; Sprūģis, E.; Rossi, Mikko; Kettunen, Heikki; Meri, R.M.; Kaparkalējs, R. (Elsevier Ltd., 2022)Proton exchange membranes (PEM), which have been commonly used in fuel cells have raised interest for the application in harsh environments involving ionizing radiation. Therefore, radiation stability and ability to sustain ... -
Proton Irradiation-Induced Reliability Degradation of SiC Power MOSFET
Niskanen, Kimmo; Kettunen, Heikki; Söderström, Daniel; Rossi, Mikko; Jaatinen, Jukka; Javanainen, Arto (Institute of Electrical and Electronics Engineers (IEEE), 2023)The effect of 53 MeV proton irradiation on the reliability of silicon carbide power MOSFETs was investigated. Post-irradiation gate voltage stress was applied and early failures in time-dependent dielectric breakdown (TDDB) ... -
Low-Power, Subthreshold Reference Circuits for the Space Environment : Evaluated with γ-rays, X-rays, Protons and Heavy Ions
Andreou, Charalambos M.; González-Castaño, Diego Miguel; Gerardin, Simone; Bagatin, Marta; Rodriguez, Faustino Gómez; Paccagnella, Alessandro; Prokofiev, Alexander V.; Javanainen, Arto; Virtanen, Ari; Liberali, Valentino; Calligaro, Cristiano; Nahmad, Daniel; Georgiou, Julius (MDPI AG, 2019)The radiation tolerance of subthreshold reference circuits for space microelectronics is presented. The assessment is supported by measured results of total ionization dose and single event transient radiation-induced ...
Ellei toisin mainittu, julkisesti saatavilla olevia JYX-metatietoja (poislukien tiivistelmät) saa vapaasti uudelleenkäyttää CC0-lisenssillä.