scholarly journals Development of a Gaseous Proton-Recoil Detector for neutron flux measurements between 0.2 and 2 MeV neutron energy

2019 ◽  
Vol 211 ◽  
pp. 03010
Author(s):  
P. Marini ◽  
L. Mathieu ◽  
M. Aïche ◽  
T. Chiron ◽  
P. Hellmuth ◽  
...  
Keyword(s):  
Neutron Flux ◽  
Cross Section ◽  
Neutron Energy ◽  
Elastic Cross Section ◽  
Proton Spectrum ◽  
Incident Neutron ◽  
High Background ◽  
Flux Measurements ◽  
Proton Recoil ◽  
Absolute Measurements

Absolute measurements of neutron fluence are an essential prerequisite of neutron-induced cross section measurements, dosimetric investigations and neutron beam lines characterisation. Independent and precise neutron flux measurements can be performed with respect to the H(n,p) elastic cross section. However, the use of silicon proton recoil detectors is not straightforward below incident neutron energy of 1 MeV, due to a high background in the detected proton spectrum. A new gaseous proton-recoil detector has been designed to answer the challenge. The detector is described in details and results of the commissioning tests are presented.

scholarly journals Development of a gaseous proton-recoil telescope for neutron flux measurements between 0.2 and 2 MeV neutron energy

2019 ◽  
Vol 124 ◽  
pp. 9-12
Author(s):  
Paola Marini ◽  
Ludovic Mathieu ◽  
Mourad Aïche ◽  
Serge Czajkowski ◽  
Beatriz Jurado ◽  
...  
Keyword(s):  
Neutron Flux ◽  
Neutron Energy ◽  
Flux Measurements ◽  
Proton Recoil

scholarly journals Towards the experimental validation of a small Time-Projection-Chamber for the quasi-absolute measurement of the fission cross section

2021 ◽  
Vol 253 ◽  
pp. 11013
Author(s):  
Carole Chatel ◽  
Ludovic Mathieu ◽  
Mourad Aïche ◽  
Maria Diakaki ◽  
Gilles Noguere ◽  
...  
Keyword(s):  
Neutron Flux ◽  
Cross Section ◽  
Neutron Energy ◽  
Cross Sections ◽  
Detection Efficiency ◽  
Silicon Detector ◽  
Fission Cross Section ◽  
Absolute Measurement ◽  
Small Time ◽  
Flux Measurements

To accurately measure neutron-induced fission cross sections, to characterize neutron-beam lines or to make dosimetric investigations, it is necessary to have high accuracy measurements of neutron fluence. It is possible to perform independent and precise neutron flux measurements with respect to the 1H(n,n)p elastic scattering cross section. The use of a silicon detector is recommended from 1 to 70 MeV neutron energy. However, it has been observed that a high electrons background forbids its use below 1 MeV. Hence, a new gaseous proton-recoil telescope is developed and characterized to overcome this limit. It should provide quasi-absolute neutron flux measurements with an accuracy around 3% and is not sensible to gamma and electrons background. It consists in two ionization chambers read by a segmented micromegas technology detection plane. The gas pressure inside is adjustable to the proton range in the detector and therefore to the neutron energy. This detector is described in details below and the newest results of its characterization are presented. A special attention is paid to detection efficiency measurements.

A Proton Recoil Monitor for Neutron Flux Measurements

1971 ◽  
Vol 42 (2) ◽  
pp. 240-243 ◽  
Author(s):  
Ronald J. Jaszczak ◽  
R. L. Macklin ◽  
M. C. Taylor
Keyword(s):  
Neutron Flux ◽  
Flux Measurements ◽  
Proton Recoil

scholarly journals Development of a gaseous proton-recoil detector for fission cross section measurements below 1 MeV neutron energy

2016 ◽  
Vol 111 ◽  
pp. 11001
Author(s):  
P. Marini ◽  
L. Mathieu ◽  
M. Aïche ◽  
S. Czajkowski ◽  
B. Jurado ◽  
...  
Keyword(s):  
Cross Section ◽  
Neutron Energy ◽  
Fission Cross Section ◽  
Proton Recoil

scholarly journals Measurement of the 235 U(n,f) cross section at n_TOF from thermal to 170 keV

2020 ◽  
Vol 50 ◽  
pp. 2060011
Author(s):  
Simone Amaducci ◽  
S. Amaducci ◽  
O. Aberle ◽  
J. Andrzejewski ◽  
L. Audouin ◽  
...  
Keyword(s):  
Neutron Flux ◽  
Cross Section ◽  
Nuclear Physics ◽  
Detection Efficiency ◽  
Neutron Cross Section ◽  
Fission Cross Section ◽  
Ratio Method ◽  
Recent Experimental Data ◽  
Silicon Detectors ◽  
Flux Measurements

The [Formula: see text]U(n,f) cross section plays a key role for nuclear physics due to its widespread use as a standard reference for neutron cross section measurements and for neutron flux measurements. Recent experimental data of the fission cross section have suggested the presence of discrepancies around 6–8% with respect to the most used libraries, precisely in the range between 10 keV and 30 keV. In order to shed light on this disagreement, an accurate measurement of the [Formula: see text]U(n,f) fission cross section has been performed at n_TOF facility @CERN, using the standard reactions 6Li(n,t) and [Formula: see text]B(n,[Formula: see text] as reference. A custom experimental setup based on a stack of silicon detectors sandwiched between pairs of [Formula: see text]U, 6Li and [Formula: see text]B targets, has been installed along the neutron beam line to intercept the same neutron flux, allowing the detection of the fission fragments and the products of the reference reactions at the same time. Such a technique allows calculation of the cross section via the “ratio method”, by normalizing the [Formula: see text]U(n,f) reaction yields with respect to the reference reactions and to the recommended data in the IAEA libraries; in particular, the integral between 7.8 and 11 eV has been chosen. Accurate Monte Carlo simulations have allowed evaluation of the neutron absorption in the different layers, as well as the detection efficiency of each detector. The data are in excellent agreement with the standard values and highlight the overestimation of the [Formula: see text]U(n,f) cross section between 9 and 18 keV in the most recent libraries.

The ‘thick-film chamber’ method for the measurement of fast neutron flux

1948 ◽  
Vol 44 (4) ◽  
pp. 581-587 ◽  
Author(s):  
K. W. Allen ◽  
D. H. Wilkinson
Keyword(s):  
Angular Distribution ◽  
Neutron Flux ◽  
Fast Neutron ◽  
Cross Section ◽  
Absolute Measurement ◽  
Experimental Results ◽  
Incident Neutron ◽  
Fast Neutron Flux ◽  
Cavendish Laboratory ◽  
Wide Range

Several methods have been developed in recent years in the Cavendish Laboratory for the absolute measurement of fast neutron flux. All depend on observing the effects of elastic collisions between neutrons and light nuclei. The methods fall into two categories according as individual recoil nuclei are counted (1, 2), or the total ionization current due to the recoils is measured (3). In order completely to interpret the experimental results, it is necessary to know the cross-section for scattering and the angular distribution of the recoil nuclei. The total number of recoil nuclei and their energy distribution are then determined for a known incident neutron spectrum. For precise neutron flux measurements, recoil protons are invariably studied, as the neutron-proton scattering cross-section has been measured over a wide range of energies (4, 5), and the angular distribution of the recoils is isotropic in the centre of gravity space for neutrons of energy less than about 10 MeV. (6, 7). This makes the reduction of the experimental results particularly simple and certain.

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