A THIRD GENERATION TOMOGRAPHY SYSTEM WITH FIFTEEN DETECTORS SIMULATED BY MONTE CARLO METHOD

Alexandre Gimenez Alvarez; Alexandre França Velo; Vagner Fernandez; Samir L. Somessari; Francisco F. Sprenger; Margarida M. Hamada; Carlos Henrique de Mesquita

doi:10.15392/bjrs.v7i2A.708

Authors

Alexandre Gimenez Alvarez IPEN/CNEN-SP
Alexandre França Velo IPEN/CNEN-SP
Vagner Fernandez IPEN/CNEN-SP
Samir L. Somessari IPEN/CNEN-SP
Francisco F. Sprenger IPEN/CNEN-SP
Margarida M. Hamada IPEN/CNEN-SP
Carlos Henrique de Mesquita IPEN/CNEN-SP

DOI:

https://doi.org/10.15392/bjrs.v7i2A.708

Abstract

This paper describes the Monte Carlo simulation, using MCNP4C, of a multichannel third generation tomography system containing a two radioactive sources ¹⁹²I (316.5 – 468 KeV) and ¹³⁷Cs (662 KeV), and a set of fifteen NaI(Tl) detectors, with dimensions of 1 inch diameter and 2 inches thick, in fan beam geometry, positioned diametrically opposite. Each detector moves 10 steps of 0,24^o, totalizing 150 virtual detectors per projection, and then the system rotate 2 degrees. The Monte Carlo simulation was performed to evaluate the viability of this configuration. For this, a multiphase phantom containing polymethyl methacralate (PMMA ((r @ 1.19 g/cm³)), iron (r @ 7.874 g/cm³), aluminum (r @ 2.6989 g/cm³) and air (r @ 1.20479E-03 g/cm³) was simulated. The simulated number of histories was 1.1E+09 per projection and the tally used were the F8, which gives the pulse height of each detector. The data obtained by the simulation was used to reconstruct the simulated phantom using the statistical iterative Maximum Likelihood Estimation Method Technique (ML-EM) algorithm. Each detector provides a gamma spectrum of the sources, and a pulse height analyzer (PHA) of 10% on the 316.5 KeV and 662 KeV photopeaks was performed. This technique provides two reconstructed images of the simulated phantom. The reconstructed images provided high spatial resolution, and it is supposed that the temporal resolution (spending time for one complete revolution) is about 2.5 hours.

Downloads

Download data is not yet available.

References

JOHANSEN G.A, HAMPEL U., HJERTAKER B. T, Flow imaging by high speed transmission tomography. Applied Radiation and Isotopes, v. 68, p. 518–524, 2010

FALAHI F. Al., Al-DAHHAN M., Experimental investigation of the pebble bed structure by using gamma ray tomography, Nuclear Engineering and Design, v. 310, p.- 231-246, 2016.

IAEA-TECDOC-1589, Industrial Process Gamma Tomography, International Atomic Energy Agency, Vienna, 2008.

MESQUITA C.H., VASQUEZ P.A.S., CALVO W.A.P., CARVALHO D.V.S., MARCATO L.A., MARTINS J.F.T., HAMADA M.M. Multi-source third generation computed tomography for industrial multiphase flows applications. In: IEEE Nuclear Science Symposium, New York, 2011, p. 1294-1302.

MESQUITA C.H., DANTAS C.C., COSTA F.E., CARVALHO D.V.S., MADI FILHO T., VASQUEZ P.A.S., HAMADA M.M. Development of a Fourth Generation Industrial Tomography for Multiphase Systems Analysis. In: IEEE Nuclear Science Symposium, New York, 2011, p. 19-23.

Disponível em <https://physics.nist.gov/cgi-bin/Star/compos.pl?matno=104>, acesso em 10 dez 2018.

MESQUITA, C.H., VELO, A.F., CARVALHO, D.V.S., MARTINS, J.F.T., HAMADA, M.M. Industrial tomography using three different gamma rays. Flow Measurement and Instrumentation, v. 47, p. 1-9, 2016.

Disponível em <https://www.inl.gov/>. Acesso em 10 dez 2018.

BENAC J. Alternating minimization algorithms for X-ray computed tomography: multigrid acceleration and dual energy application, Tese (Ph.D), Washington University, St. Louis, 2005.

SALGADO, C.M., BRANDÃO L.E.B., SCHIRRU, R., PEREIRA, C.M.N.A. CONTI C.C. Validation of a NaI(Tl) detector's model developed with MCNP-X code. Progress in Nuclear Energy, v. 59, p. 19-25, 2012.

JEHOUANI, A., ICHAOUI, R., BOULKNEIR, M. Study of the NaI(Tl) efficiency by Monte-Carlo method. Applied Radiation and Isotopes, v. 53, p. 887-891, 2000.

VELO A.F, HAMADA M.M., CARVALHO D.V.S., MARTINS J.F.T, MESQUITA C.H., A portable tomography system with seventy detectors and five gamma-ray sources in fan beam geometry simulated by Monte Carlo method. Flow Measurement and Instrumentation, v. 53, p. 89-94, 2017.

HADIZADEH YAZDI M.H., MOWLAVI A.A., THOMPSON M.N., MIRI HAKIMABAD H. Proper shielding for Na(Tl) detectors in combined neutron-gamma fields using MCNP. Nuclear Instruments and Methods in Physics, v. 522, p. 447-454, 2004.

PELOWITZ, D.B. MCNP-X TM, User’s Manual, Version 2.5.0, LA-CP-05-0369. Los Alamos National Laboratory (2005).

MAAD R., HJERTAKER B.T., JOHANSEN G.A, OLSEN Ø. Dynamic characterization of a high speed gamma-ray tomography. Flow Measurement and Instrumentation, v. 21, p. 538-545, 2010.