Propagation of Errors from Response Functions to Unfolded Spectrum

Shin, Kyuchul; Uwamino, Yoshitomo; Hyodo, Tomonori

doi:10.13182/nt81-a17059

Cited by 39 publications

(8 citation statements)

References 3 publications

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“…The program can discriminate different particle species according to the protocol which can be flexibly given by a user. For neutrons, the energy spectra can be derived by using the FERDO-U unfolding code 7) . Data acquisition status can be monitored on display in real time.…”

Section: Monitoring Systemmentioning

confidence: 99%

Development of Cosmic Radiation and Energetic Particle Analyzing System: CREPAS

Yasuda¹,

Yajima²,

Takada³

et al. 2011

Progress in Nuclear Science and Technology

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Information on the accurate spectrum of energetic cosmic-ray particles, particularly neutrons and protons, are important for radiological protection of aircraft crew. However, verification of cosmic radiation doses in aircraft is still difficult because detector signals attributing to different radiation components are mixed and hardly separated by means of a conventional, transportable radiation instrument. We have thus developed a new monitoring system "CREPAS" composed of a phoswich-type scintillation detector coupled with a high-speed data acquisition unit which can measure the waveform of 0 to 5 V signals from -20 to 400ns with 2ns intervals; the waveform data of 12-bit dynamic range are transferred to a personal computer via USB2.0 interface. The signal waveforms are analyzed on site in real time for discrimination of different radiation components such as neutrons, protons, muons/electrons and gamma rays. In order to examine its feasibility, CREPAS was exposed to accelerator beams and then used for cosmic radiation measurements at the summit of a high mountain and in a chartered jet aircraft. It was verified that this system can successfully measure cosmic-ray energetic neutrons (>10MeV) separately from other components. Determination of the precise energy spectra of neutrons and other components calls for further investigation.

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Section: Monitoring Systemmentioning

confidence: 99%

Development of Cosmic Radiation and Energetic Particle Analyzing System: CREPAS

Yasuda¹,

Yajima²,

Takada³

et al. 2011

Progress in Nuclear Science and Technology

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“…The created neutron and photon response matrices were used to obtain the neutron and photon energy spectra in the experimental flights 18) by coupling with the FERDOU unfolding code. 32) …”

Section: Response Matricesmentioning

confidence: 99%

Response Functions of Phoswich-Type Neutron Detector for High-Energy Cosmic Ray Neutron Measurement

Takada¹,

Yajima²,

Yasuda³

et al. 2010

J. Nucl. Sci. Technol.

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A phoswich-type neutron detector was developed in order to measure high-energy cosmic ray neutron spectra in aircraft. The neutron detector consists of an EJ309 organic liquid scintillator that is 121.7 mm in diameter and 121.7 mm in length and is covered with a 15 mm thick EJ299-13 outer plastic scintillator. The neutron response functions of the detector are required for the unfolding method to obtain the energy spectrum. The neutron response functions were created based on MCNPX simulations using an anticoincidence mode with the experimental light-output correlations with particle energies, uniformity of light collection and energy resolutions. The light-output correlation with particle energy, the uniformity of light collection and the energy resolutions were evaluated based on experiments. Measurements of neutron response functions were performed using four quasi-monoenergetic neutron beams from 40 to 80 MeV pLi reactions to verify the calculated results. The calculated response functions show good agreement with the measurements. The angular response of the phoswich detector was confirmed to be isotropic from the calculation. The photon response functions of the detector were also calculated and agreed well with the measurements for 6.129 MeV photons. Neutron and photon response matrices were created up to 300 and 50 MeV, respectively, over a wide energy range for experimental flights.

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“…Neutron and photon energy spectra were obtained using the FERDOU unfolding method; 18) we created their response matrices 10) on the basis of the MCNPX calculation 7) with a source geometry of an upper hemisphere over the phoswich detector. The maximum energies of the response matrices were 300 MeV for neutrons and 50 MeV for photons in order to measure cosmic-ray particles over a wide energy range.…”

Section: ) (4) Neutron and Photon Response Matricesmentioning

confidence: 99%

“…Errors in the unfolding process of the FERDOU code 18) from statistical count errors were determined to be 6.9% for neutrons and 8.8% for photons ( Table 1). Errors for neutrons were estimated as 20.3, 1.9, and 12.4% from 7-30, 30-100, and 100-180 MeV, respectively.…”

Section: Uncertainties In Energy Spectramentioning

confidence: 99%

“…11 from 4 to 50 MeV at the aviation altitude (249 g/cm 2 atmospheric depth, 10.2 GV vertical cut-off rigidity) and a heliocentric potential of 312 MV. The spectrum was obtained by the unfolding method using the FERDOU code 18) with the photon response matrix given by Takada Fig. 11 Photon energy spectrum, measured using a phoswich neutron detector, an altitude of 10.8 km (atmospheric depth of 249 g/cm 2 ) and geographical latitude of 39 N (at vertical cut-off rigidity of 10.2 GV) on February 13, 2008 (at a heliocentric potential of 312 MV).…”

Section: Photon Energy Spectrummentioning

confidence: 99%

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Measurement of Atmospheric Neutron and Photon Energy Spectra at Aviation Altitudes using a Phoswich-Type Neutron Detector

Takada¹,

Yajima²,

Yasuda³

et al. 2010

Journal of Nuclear Science and Technology

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Neutron energy spectrum from 7 to 180 MeV and photon energy spectrum from 4 to 50 MeV were measured onboard an aircraft using a newly developed phoswich-type neutron detector at 10.8 km altitude (atmospheric depth of 249 g/cm 2 ) and geographical latitude of 39 N (a vertical cut-off rigidity of 10.2 GV) near Japan on February 13, 2008 (at a heliocentric potential of 312 MV). Our results were compared with other measurements obtained using 3 He-loaded or extended-energy multi moderator neutron spectrometers (Bonner balls) at aviation altitudes, an organic liquid scintillator on the ground, and a double-scatter neutron telescope at the top of the atmosphere and with calculations using the LUIN2000, EXPACS and RMC codes. Our measured results give a large, sharp peak around a neutron energy of 70 MeV, although Bonner balls present a broad peak around 100 MeV due to low energy resolution. Our neutron fluxes agree well with the others. The measured photon energy spectrum is between the LUIN2000-and EXPACS-calculated spectra and agrees with measured vertical photon spectra at the top of the atmosphere. This onboard study provides the first experimental neutron energy spectrum in the high-energy region (over 10 MeV) with a high energy resolution.

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Propagation of Errors from Response Functions to Unfolded Spectrum

Cited by 39 publications

References 3 publications

Development of Cosmic Radiation and Energetic Particle Analyzing System: CREPAS

Development of Cosmic Radiation and Energetic Particle Analyzing System: CREPAS

Response Functions of Phoswich-Type Neutron Detector for High-Energy Cosmic Ray Neutron Measurement

Measurement of Atmospheric Neutron and Photon Energy Spectra at Aviation Altitudes using a Phoswich-Type Neutron Detector

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