Development of a procedure for hyper-pure germanium detector response calibration combining experimental measurements with Monte Carlo simulations

• Applicant: Professor Dr. Lorenzo Brualla Barbera
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
• Term: from 2011 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 200971961

• Final Report Year: 2014

Final Report Abstract

Although the HPGe detector was ordered to ORTEC by our Brazilian partners upon the start of the project, it was not received until June 22nd, 2012. This delay forced us to start working with another smaller HPGe detector. Owing to the findings of the first two articles we were motivated to study the effect that modifications of the atomic form factors of Rayleigh scattering have in the simulated detection efficiency. Several modifications were tested but up until now the results are inconclusive. Nevertheless, we continue investigating this line of research. During the project the German applicant has coded a Fortran program that automatically generates the geometry of an HPGe detector with the dead layer dimensions provided by the user, together with the necessary input files in order to run a PENELOPE simulation. The tallied energy spectrum produced by the execution of this program serves as input of a Mathematica program coded by the Brazilian group. This Mathematica code processes the experimental and simulated energy spectra and compares them. We are now preparing a manuscript for reporting about this suit of programs that will be made freely available. During the project we have not conducted the studies on the electric field in the HPGe crystal and electric charge trapping. We plan to start with these tasks once the research on atomic form factors and Compton interaction cross sections, that was not foreseen, has reached a conclusion. Although funding from DFG finalized on October 2013, the work on the tasks proposed in the project has continued. As it has been already written, there are still several unconcluded areas within the project in which we will continue to work.

Publications

• A combined approach of variance-reduction techniques for the efficient. Monte Carlo simulation of linacs Phys. Med. Biol. 3013–3024, 57, 2012
  M. Rodriguez, J. Sempau, L. Brualla
  
• Measurement of peripheric dead layers in HPGe x-ray detectors. 2012 International Symposium on Radiation Physics (ISRP 2012), Rio de Janeiro, Brazil. October 2012
  N.L. Maidana, V.R. Vanin, V. Jahnke, W. Godoy, J.M. Fernandez, M.N. Martins, L. Brualla
  
• Retinoblastoma external beam photon irradiation with a special ‘D’-shaped collimator: a comparison between measurements, Monte Carlo simulation and a treatment planning system calculation. Phys. Med. Biol. 7741–7751, 57, 2012
  L. Brualla, P.A. Mayorga, A. Fl¨hs, A.M. Lallena, J. Sempau, W. Sauerwein
  
• Accurate estimation of dose distributions inside an eye irradiated with 106Ru plaques. Strahlenther. Onkol. 68–73, 189, 2013
  L. Brualla, J. Sempau, F.J. Zaragoza, A. Wittig, W. Sauerwein
  
• Efficiency calibration of x-ray HPGe detectors for photons with energies above the Ge K binding energy. Nuclear Instruments and Methods in Physics Research A, 729 (2013) 371–380
  N.L. Maidana, V.R. Vanin, V. Jahnke, J.M. Fernández-Varea, M.N. Martins, L. Brualla
  
• PRIMO: A graphical environment for the Monte Carlo simulation of Varian and Elekta linacs. Strahlenther. Onkol. 881–886, 189, 2013
  M. Rodriguez, J. Sempau, L. Brualla
  
• Electron beam quality kQ,Q0 factors for various ionization chambers: a Monte Carlo investigation with PENELOPE Phys. Med. Biol. 6673–6691, 59, 2014
  F. Erazo, L. Brualla, A. Lallena
  
• Efficiency simulation of a planar detector with a non-uniform frontal dead layer. European Conference on X-Ray Spectrometry (EXRS), Bologna, Italy. June 2014
  N.L. Maidana, V.R. Vanin, L. Brualla
  
• Monte Carlo simulation of TrueBeam flattening-filter-free beams using Varian phase-space files: Comparison with experimental data Med. Phys. 051707 (pp. 11), 41, 2014
  M.F. Belosi, M. Rodriguez, A. Fogliata, L. Cozzi, J. Sempau, A. Clivio, G. Nicolini, E. Vanetti, H. Krauss, C. Khamphan, P. Fenoglietto, J. Puxeu, D. Fedele, P. Mancosu, L. Brualla
  
• Monte Carlo study for designing a dedicated “D”-shaped collimator used in the external beam radiotherapy of retinoblastoma patients. Med. Phys. 011714 (pp. 12), 41, 2014
  P.A. Mayorga, L. Brualla, W. Sauerwein, A.M. Lallena
  
• Technical Note: Influence of the phantom material on the absorbed-dose energy dependence of the EBT3 radiochromic film for photons in the energy range 3 keV–18 MeV. Med. Phys. 112103 (pp. 6), 41, 2014
  M. Hermida-López, L. Lüdemann, A. Flühs, L. Brualla
  
• Determination of the detection efficiency of a planar HPGe detector with a non-uniform frontal dead layer. X-Ray Spectrometry, Volume 44, Issue 3. Special Issue: Presented at the European Conference on X‐Ray Spectrometry, Bologna, Italy, 15–20 June 2014, May/June 2015, Pages 89-92
  L. Brualla, N.L. Maidana, V.R. Vanin
  
• Monte Carlo simulation of the treatment of eye tumors with 106 Ru plaques: A study on maximum tumor height and eccentric placement Ocul. Oncol. Pathol. 1–11, 1, 2015
  L. Brualla, F. Zaragoza, W. Sauerwein