TEPC-FLUKA Comparison
1. Name of Experiment:
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TEPC-FLUKA Comparison
2. Purpose and Phenomena Tested:
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Measurements and simulation of the lineal energy distribution of the energy deposition
in biological cells of 2µm diameter. This is first done in well characterized mixed
radiation field in order to evaluate the response of the instrument. The comparison
is then repeated in the complex cosmic ray environment on board of an aircraft.
3. Description of the Source and Experimental Configuration:
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Sources:
Pure photon: Co60
Pure Neutron: 0.5 MeV at PTB
Mixed Field: AmBe without lead cap
High energy field: CERN-EU High Energy Reference Field (CERF) facility [1]
(Positively charged hadron beam (mixture of protons and pions) with 120 GeV/c momentum
on copper target producing secondaries passing through 80 cm concrete shielding. The
resulting neutron spectrum has two maximum at about 1 Mev and 70 MeV) similar to the
high-energy component of the radiation field created by cosmic rays at commercial
flight altitudes.)
Radiation field at commercial flight altitude.
4. Measurement System and Uncertainties:
------------------------------------
The detectors used were:
A Tissue Equivalent Proportional Counter (TEPC) is a standard instrument for
measurements in a mixed radiation field. Particularly in aircrew radiation dosimetry
the TEPC is of major interest for usage as a reference instrument. It measures the
microdosimetric distribution d(y) of absorbed dose as a function of the lineal energy
y over up to five orders of magnitude.
Dose equivalent is calculated folding this distribution with the quality factor as a
function of linear energy transfer (LET), as defined in ICRP74.
The TEPC instrument used at the Austrian Research Center Seibersdorf (ARCS) is a sphere
of 125 mm inner diameter. Since the TEPC is filled with pure propane gas, at low
pressure (933.2 Pa) it simulates a tissue volume with a diameter of 2µm. The wall of
the sphere is made of a tissue equivalent plastic (A150). The TEPC sphere is contained
in an aluminum cylindrical structure together with the required electronics. The
complete assembly, cased inside a portable trolley of an aircraft hand-baggage
dimension, is called HAWK [2].
The geometry of TEPC is shown on tepc-geo.jpg, and the corresponding material
composition in the file tepc-mat.xls.
5. Description of Results and Analysis:
-----------------------------------
The response of a Tissue Equivalent Proportional Counter (TEPC) has been simulated with
the Monte Carlo transport code FLUKA[3]. Absorbed dose rate and ambient dose equivalent
rate distributions as a function of lineal energy have been simulated for several
reference sources and mixed radiation fields. The comparison between the simulated and
measured microdosimetric spectra in these standard fields show a good agreement.
The Monte Carlo code FLUKA has also been used to calculate the radiation field at aircraft
altitudes to simulate the TEPC response to this field. This simulation have been compared
with TEPC in-flight measurements done at the same geographical position, altitude and same
solar condition. The microdosimetric spectra measured within the aircraft shows a
reduction of the high-LET contribution compared with the one simulated in free atmosphere.
This reduction can be due to the influence of the aircraft structures.
6. Special Features:
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None
7. Author/Organizer
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Experiment and analysis:
M. Autischer(1), P. Beck(1), A. Ferrari(2), M. Latocha(1), M. Pelliccioni(3),
S. Rollet(1) and R. Villari(3)
(1) Austrian Research Centre Seibersdorf, A-2444 Seibersdorf, Austria
(2) CERN, 1211 Geneva 23, Switzerland
(3) INFN, Laboratori Nazionali di Frascati, 00044 Frascati, Italy
Compiler of data for Sinbad:
S. Rollet
Austrian Research Centre Seibersdorf, A-2444 Seibersdorf, Austria
Reviewer of compiled data:
I. Kodeli
OECD/NEA, 12 bd des Iles, 92130 Issy les Moulineaux, France
8. Availability:
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Restricted
9. References:
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[1] Mitaroff, A. and Silari, M., The CERN-EU High-Energy Reference Field
(CERF) Facility for Dosimetry at Commercial Flight Altitudes and in
Space, Rad. Prot. Dosim. Vol.102, No. 1. pp.7-22, (2002).
[2] Far West Techn. Inc., Environmental radiation monitor with 5 inches
tissue equivalent proportional counter, Operations and repair manual,
December, (2000).
[3] Fasso, A., Ferrari, A., Ranft, J., Sala, P.R., FLUKA: Status and Prospective
for Hadronic Applications Proc. of the MonteCarlo 2000 Conference, Lisbon,
October 23–26 2000, Springer-Verlag Berlin, p. 955-960, (2001).
[4] S. Rollet, P. Beck, A. Ferrari, M. Pelliccioni, M. Autischer, Dosimetric
Considerations on TEPC FLUKA-Simulation and Measurements, Rad. Prot. Dosim.,
Vol. 110, Nos 1-4, pp. 833-837 (2004)
[5] P. Beck, A. Ferrari, M.Pelliccioni, S. Rollet and R. Villari,
FLUKA Simulation of TEPC Response to Cosmic Radiation
10. Data and Format:
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Filename Size[bytes] Content
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1 tepc-fluka.htm 10,044 This information file
2 tepc-fluka.pdf 184,156 Detailed description and reference paper for comparison with
standard sources.
3 cosmic-fluka.pdf 116,218 Detailed description and reference paper for comparison
onboard of aircraft.
4 fig1.pdf 84,775 Sketch of the geometry layout of a HAWK simulated with FLUKA.
5 fig2.pdf 191,551 Simulated Microdosimetric spectra y d(y) for photon sources at
different energies.
6 fig3.pdf 150,085 Microdosimetric spectra y d(y) for a 60Co source.
Comparison between simulation and measurements.
7 fig4.pdf 145,315 Microdosimetric spectra y d(y) for a 0.5 MeV neutron source.
Comparison between simulation and measurements.
8 fig5.pdf 197,820 Microdosimetric spectra y d(y) for an 241AmBe source.
Comparison between simulation and measurements.
9 fig6.pdf 212,922 Microdosimetric spectra y d(y) for the reference source at CERF.
Comparison between simulation and measurements.
10 tepc-geo.jpg 47,128 TEPC geometry
11 tepc-mat.xls 15,872 TEPC material composition
12 meas_raw.xls 83,456 Raw data of TEPC measurements at CERF (position CT10)
13 CERF-comp.xls 152,576 Comparison between measurements and simulations data at CERF
(plot and data)
14 phospc.dat 4,285 Photon energy spectrum at CT10 (data)
15 phospc.pdf 12,890 Photon energy spectrum at CT10 (plot)
16 neuspc.dat 4,565 Neutron energy spectrum at CT10 (data)
17 neuspc.pdf 14,466 Neutron energy spectrum at CT10 (plot).
Data and plots at commercial flight altitude.
18 prispc.pdf 18,128 Plot of the primary energy spectra at the top of the atmosphere
(particles with Z up to 26)
19 fig1a.pdf 9,331 Simulated spectral neutron fluence
20 fig1b.pdf 8,083 Simulated microdosimetric neutron spectra yd(y) as seen by TEPC
21 fig2a.pdf 7,412 Simulated spectral proton fluence
22 fig2b.pdf 8,059 Simulated microdosimetric proton spectra yd(y) as seen by TEPC
23 fig3a.pdf 8,186 Simulated spectral photon fluence
24 fig3b.pdf 8,058 Simulated microdosimetric photon spectra yd(y) as seen by TEPC
25 fig4a.pdf 9,330 Simulated spectral electron+positron fluence
26 fig4b.pdf 8,056 Simulated microdosimetric electron+positron spectra yd(y) as seen by TEPC
27 cosm.pdf 13,453 Simulated microdosimetric spectra yd(y) for all particles + total
28 flight-comp.pdf 9,092 Microdosimetric spectra yh(y) comparison between simulation
(in free atmosphere) and measurements (inside the aircraft)
SINBAD Benchmark Generation Date: 7/2005
SINBAD Benchmark Last Update: 7/2005
