Mixed-Field Dosimetry of a Fast Neutron Beam at the Portuguese Research Reactor for the Irradiation of Electronic Circuits – Measurements and Calculations

Superheated droplet detectors (SDDs) have been investigated for applications in neutron dosimetry and spectrometry. Varying the detector temperature, it is possible to change the neutron energy detection threshold of SDDs, thus allowing the use of a single detector to measure neutrons of different energy, without any change of the experimental setup. However, the neutron threshold energy versus temperature curves have to be experimentally determined. The determination of the calibration curves requires the use of monochromatic neutron beams.The neutron spectrum from a nuclear reactor covers a wide energy range, from meV to several MeV. Beams of quasi-monochromatic neutrons can be generated by filtering neutrons emerging from the core with suitable materials, such as Fe (for 24 keV neutrons) and Si (144 and 54 keV). These materials have windows in their neutron cross-sections, so that neutrons corresponding to these windows are transmitted, whereas neutrons with other energies are attenuated.We report on the MCNP simulation study of passive monochromators of Si þ S and Si þ Ti for the production of quasimonochromatic neutron beams of 54 keV ðSi þ SÞ and 144 keV ðSi þ TiÞ. The simulations allowed the purity versus intensity of the neutron beams to be optimized, within the geometrical constraints of the beam port. r

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“…The radiation field determined in Ref. [6] for position A in Fig. 1 was used as the source term in the present work.…”

Section: The Source Termmentioning

confidence: 99%

Optimization of filtered neutron beams for the calibration of superheated droplet detectors at the RPI

Nascimento

Ramos

Fernandes

et al. 2007

Nuclear Instruments and Methods in Physics Research Section A:

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“…The spectrum in the irradiation cavity was simulated using the Monte-Carlo code MCNP-4C, using a detailed three-dimensional model of the core validated with extensive measurements in the core region [5]. The calculated spectrum was adjusted to measurements using sets of activated foils with different energy-dependent cross sections, following a procedure previously described [6]. Fig.…”

Section: Description Of Tested Isolation Devicesmentioning

confidence: 99%

“…Table II shows are 40% higher than the total fluence above 1 MeV for the neutron spectrum in the irradiation cavity, as determined in ref. [6].…”

Section: Description Of Tested Isolation Devicesmentioning

confidence: 99%

Radiation tolerant isolation amplifiers for temperature measurement

Zong

Franco

Agapito

et al. 2006

Nuclear Instruments and Methods in Physics Research Section A:

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Abstract:This paper concentrates on the selection of radiation tolerant isolation amplifiers, which are suitable for the signal conditioners for cryogenic system in the Large Hadron Collider (LHC). The evolution and the results of different commercial isolation amplifiers' parameters under neutron and gamma radiation are presented. In most cases, the tested isolation amplifiers' input offset voltage, bias currents and output offset voltage hardly changed during the radiation. The DC gain in input stage was only affected for some isolation amplifiers with a small open loop gain. Transmission coefficient showed decrease for all the tested isolation amplifiers. Also, the DC output voltage increased and the ripple voltage decreased for all the build in isolated regulators. In addition, results on 1B41 signal conditioner showed that it was tolerant to 7-8·10¹²n/cm², which was 50 % higher than the expected dose in the LHC. Radiation Tolerant Isolation Amplifiers for Temperature Measurement

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“…The actual spectrum in the irradiation cavity was simulated using the Monte-Carlo code MCNP-2 4C, using a detailed three-dimensional model of the core validated with extensive measurements in the core region [5]. The calculated spectrum was further adjusted to activation measurements using sets of foils with different energy-dependent cross sections, following a procedure previously described [6]. For the neutron spectrum in the irradiation cavity, the fluences obtained in this way with the Ni foils are 40% higher than the total fluence above 1 MeV, determined using multiple foils as described in ref.…”

Section: Irradiation Facilitymentioning

confidence: 99%

Radiation tolerant D/A converters for the LHC cryogenic system

Franco

Zong

Agapito

et al. 2005

Nuclear Instruments and Methods in Physics Research Section A:

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The electronic instrumentation of the LHC cryogenic system is supposed to receive a large dose of total radiation dose (10 This paper focuses on the selection of a radiation tolerant 12-bit parallel input D/A converter, suitable for the system requirements. During a preliminary campaign, some candidates were irradiated to determine the most tolerant device. Once it was discovered, a massive test on this converter was carried out. In this second test, some weak points of the device, as the rad-sensitive voltage reference and the presence of a transresistor, had been removed by means of an external voltage source and a rad-tol op amp.Thus, tests show that the whole system consisting of the D/A converter, external reference and rad-tol op amp could tolerate a total radiation dose up to 5·10

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Mixed-Field Dosimetry of a Fast Neutron Beam at the Portuguese Research Reactor for the Irradiation of Electronic Circuits – Measurements and Calculations

Cited by 6 publications

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Optimization of filtered neutron beams for the calibration of superheated droplet detectors at the RPI

Optimization of filtered neutron beams for the calibration of superheated droplet detectors at the RPI

Radiation tolerant isolation amplifiers for temperature measurement

Radiation tolerant D/A converters for the LHC cryogenic system

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