de Blas, A.; Toral, J.; Tapia, C.; Riego, A.; Garcia, R.; Dies, J.; Batalla, E.; Diaz, P. IEEE transactions on nuclear science Vol. 63, num. 3, p. 1526-1530 DOI: 10.1109/TNS.2015.2489460 Data de publicació: 2016-06 Article en revista
This paper describes an equipment for continuous measurement and identification of gamma radioactivity in aerosols developed by the Nuclear Engineering Research Group (NERG) at the Technical University of Catalonia (UPC) and Raditel Serveis i Subministraments Tecnològics, Ltd. A spectrometric analysis code has been specially designed for it. Spectrum analysis identifies and determines activity concentration of aerosol emitters captured by a fiberglass paper filter. This new equipment is currently operating in three radioactivity monitoring stations of the Environmental Radiological Surveillance Network of the Generalitat of Catalunya (local Catalan government): two near Ascó and Vandellòs Nuclear Power Plants in the province of Tarragona and one in the city of Barcelona. Two more monitors are expected to be deployed at Roses, Girona, Spain, and Puigcerdà, Barcelona, Spain. Measurements and evolution analysis results of emitters identified at these stations were also provided.
de Blas, A.; Riego, A.; Garcia, R.; Tapia, C.; Dies, J.; Toral , J.; Batalla, E.; Diaz, P. IEEE transactions on nuclear science Vol. 63, num. 3, p. 1578-1585 DOI: 10.1109/TNS.2016.2521388 Data de publicació: 2016-06 Article en revista
This paper presents a new code for the analysis of gamma spectra generated by an equipment for continuous measurement of gamma radioactivity in aerosols with paper ¿lter. It is called pGamma and has been developed by the Nuclear Engineering Research Group at the Technical University of Catalonia - Barcelona Tech and by Raditel Serveis i Subministraments Tecnològics, Ltd. The code has been developed to identify the gamma emitters and to determine their activity concentration. It generates alarms depending on the activity of the emitters and elaborates reports. Therefore it includes a library with NORM and arti¿cial emitters of interest. The code is being adapted to the monitors of the Environmental Radiological Surveillance Network of the local Catalan Government in Spain (Generalitat de Catalunya) and is used at three stations of the Network.
Cot, A.; Jané, E.; Sempau, J.; Falcón, C.; Bullich, S.; Pavía, J.; Calviño, F. IEEE transactions on nuclear science Vol. 53, num. 1, p. 198-203 DOI: 10.1109/TNS.2006.870174 Data de publicació: 2006-02 Article en revista
I is a commonly used radioisotope employed
in neurotransmitter SPECT studies. In addition to an intense
line at 159 keV, the decay scheme of this radioisotope includes
a low yield ( 3%) of higher energy photons which make a
non-negligible contribution to the final image when low-energy
high-resolution (LEHR) collimators are used. This contribution
of high-energy photons may reach 28% of the total counts in
the projections. The aim of this work is to model each energy
component of the high-energy Point Spread Function (hPSF)
for fan-beam LEHR collimators in order to develop fast Monte
Carlo (MC) simulations of high-energy ray contamination. The
modeling of hPSF was based on the results of simulating photons
through the collimator-detector system using the MC code PENELOPE.
Since low-energy PSFs models for fan-beam collimators
tend to a Gaussian distribution, we use the same function for
the hPSF modeling for high-energy photons. The parameters of
these Gaussian functions ( ( )) were obtained by minimizing
the root mean square error (RMS) using the sensitivity of the
simulated hPSFs as a constraint. The hPSFs were parameterized
for a range of energies between 350 keV and 538 keV. The RMS
attained after fitting of ( ) to the simulated hPSFs was always
smaller than 2% of the mean sensitivity per pixel of the image.
A strong dependence of the sensitivity on the type and thickness
of the backscatter material behind the crystal was found. Our
results indicate that Gaussian distributions approximate the hPSF
responses for fan-beam collimators. This model will be an important
tool to accelerate MC simulations of radiolabeled compounds
which emit medium- or high-energy rays.
Cot, A.; Sempau, J.; Pareto, D.; Bullich, S.; Pavía, J.; Calviño, F.; Ros, D. IEEE transactions on nuclear science Vol. 49, num. 1, p. 12-16 DOI: 10.1109/TNS.2002.998674 Data de publicació: 2002-05 Article en revista
A computer model to evaluate radiation damage on AlGaAs-based solar cells is reported. The model is based on a piecewise approach that divides the cell structure in an adaptive number of slices. Inside a particular slice the semiconductor parameters are constant; consequently, it is easy to find an analytical solution of the semiconductor transport equations with suitable boundary conditions for the interfaces with the adjacent slices. The model provides all electrical parameters of the cells in the operating temperature range. Different structures, including graded band gaps and double heterofaces can be analyzed. Proton damage coefficients as well as proton damage ratios can be calculated for energies between 30 and 10/sup 4/ keV with only two adjustable parameters. Coirradiation experiments with different energy protons were simulated by improving the conventional method of degradation computering.
Roux, M.; Bernard, J.; Reulet, R.; Bielle-Daspet, D.; Lagouin, M.; Castañer, L.; Bourgoin, J.; Crabb, R. IEEE transactions on nuclear science Vol. 30, num. 6, p. 4162-4168 Data de publicació: 1983-01 Article en revista