Construction and evaluation of an α-particle-irradiation exposure apparatus
Creators: name: Nikitaki, Zacharenia
name: Choulilitsa, Evangelia
name: Kalospyros, Spyridon A.
name: Kaisaridi, Sofia
name: Terzoudi, Georgia I.
name: Kokkoris, Mike
name: Georgakilas, Alexandros G.
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Biophysics
subject: 29999 Physical Sciences not elsewhere classified
subject: FOS: Physical sciences
subject: Biotechnology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: FOS: Biological sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: Developmental Biology

description: The development of an exposure apparatus for in situ α-irradiation studies of cells. The construction of the apparatus is simple and the apparatus is maintenance free, easy to use and of low cost. This small device can be placed in an incubator, where the exposure environment is controlled. Moreover the vapour saturated incubator protects the cells from drying out, allowing long irradiation intervals. <b>Materials and Methods:</b> The system includes a <sup>234</sup>U alpha (α)- source of total activity 0.77 ± 0.03 MBq in the form of a thin disk deposited on an aluminium substrate. The α-particles emitted in the air have a mean energy of 4.9 MeV at the disk surface. Source homogeneity has been studied via Rutherford Backscattering Spectrometry. Using SRIM 2013 and Monte Carlo (MC) simulations via the MCNP6.1 code, LET and energy deposition values have been calculated for various filling gasses. Furthermore, based on these simulations, the assembly’s dimensions and equivalent irradiation rate have been determined. With respect to the aforementioned dimensions, the experimental setup is constructed in a way to provide uniform irradiation of the sample. Using <i>Sacalc3v1.4</i> irradiation radial homogeneity has been studied. In order to evaluate biologically our apparatus, the well-established chromosomal aberration assay has been utilized, applied in exponentially growing hamster (CHO) cells. Furthermore, immunofluorescence assay has been performed as a ‘biological detector’, in order to validate α-particles surface density. The final stage of this study is the estimation of complex DNA damage, using fast Monte Carlo Damage Simulation (MCDS) code. <b>Results:</b> Source surface homogeneity: emission deviations do not exceed 10-15%. The optimal distance between the source and the cells for irradiation is determined to be 14.8 mm. Irradiation radial homogeneity: a deviation of 5% occurs at the first 8 mm from the center of the irradiation area, and a 10% deviation occurs after 12mm. Chromosomal aberrations were found in good accordance with the corresponding in bibliography. <b>Conclusions:</b> This technical report describes analytically the stages concerning this experimental housing; from MC simulations to the irradiation of mammalian cells and data analysis. Moreover, guidance is provided as well as a report of the variables on which critical parameters are depended, so as to make this work useful to anyone who wants to construct a similar in-house α-irradiation apparatus.