IMPLEMENTACIÓN DE SISTEMAS EMBEBIDOS
Geiger-Müller counter implementation with an 8-bit microcontroller Husain, Ignacio Santiago
García-Inza, Mariano
Lipovetzky, José
[email protected]
[email protected]
[email protected]
School of Engineering University of Buenos Aires Buenos Aires, Argentina
Device Physics-Microelectronics Lab School of Engineering University of Buenos Aires Buenos Aires, Argentina
Low Temperature Division Bariloche Atomic Center CNEA Río Negro, Argentina
Objectives
Experimental arrangements
a low-cost ionizingradiation-measurement system using Geiger-Müller (GM) tube. • Validate measurements against an homologated commercial pancake-type GM counter [4], using a partially shielded 90 Sr radiation source. R AT89S8253 8• Use Atmel's bit microcontroller.
• The system was tested with two dierent tubes [3] (although the
• Build
Si3bg tube produced no CPS)valuating their response as a function of distance to the source, and also varying their biasing voltage. • A shielded 100 mCi 90 Sr source was used. The decay of 90 Sr produces beta particles (high energy electrons) and a small fraction (0.02%) of 1.76MeV gamma photons. The shielding of the source is designed to completely stop the beta particles, but allows the transmission of a high fraction of the gamma photons, which are the ones we detect with the GM Tube.
Conclusions
• Prototype suitable for low dose
Figure 1: DosemeterTubes:Si3bg(U),SBM-20(D)Dosemeter and
Experiment 1: CPS vs. distance
We
thank
the
Microelectronics
Device Lab
at
PhysicsFIUBA,
for providing the radioactive source and the commercial counter, as well as their expertise in the eld, and also to the professors of FIUBA's course 66.09 Laboratorio de Microcomputadoras.
Sr
Experiment 2: CPS vs. SBM−20 tube’s biasing voltage
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30 Experimental data for SBM−20 1/r2 data fitting for SBM−20 Experimental data for Galert 500P+
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1/r2 data fitting for Galert 500P+
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CPS
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0 20
Acknowledgements
90
Results
CPS
detection applications as personnel dosimetry. • GM tube measured CPS is 0.3789 times the ones obtained with the commercial counter, permitting a rough calibration of our system. • SBM-20 tube and Pancake detector area ratio is 0.5, so less sensitivity was obtained using GM tube. • Measurements show that the radioactive element can be seen as a spherical source, as shown in Fig. 2.
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Figure 2: CPS vs. Distance(Left); CPS vs. biasing voltage(Right) References [1] F.G. Knoll, Radiation detection and measurement, John Wiley & Sons, 2010. [2] C. Amsler, M Doser, M Antonelli, D.M. Asner, K.S. Babu, H. Baer, A.V. Gritsan, Review of particle physic., Physics Letters B, No. 667(1), pp 1-6, 2008. [3] SBM-20 and Si3bg Tube's Datasheets: gstube.com/data/2398/ and /2486/ [4] GammaSys Detector Manual: gammasys.com.ar/product5.html
