scholarly journals Time-resolved secondary triton burnup 14 MeV neutron measurement by a new scintillating fiber detector in middle total neutron emission ranges in deuterium large helical device plasma experiments

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
K. Ogawa ◽  
M. Isobe ◽  
S. Sangaroon ◽  
E. Takada ◽  
T. Nakada ◽  
...  
Keyword(s):  
Neutron Source ◽  
Detection Efficiency ◽  
Neutron Emission ◽  
High Temporal Resolution ◽  
Emission Rates ◽  
Total Neutron ◽  
Neutron Measurement ◽  
Discrimination Ability ◽  
Mhd Instability ◽  
Scintillating Fiber

AbstractA middle-sensitivity scintillating fiber detector (hereafter middle Sci-Fi detector) that works at a deuterium-tritium neutron flux of ~105-107 cm−2s−1 was utilized to measure secondary deuterium-tritium neutron emission rates with high temporal resolution at a total neutron emission rate of 1013 to 1015 n/s, where strong magnetohydrodynamic (MHD) instabilities were observed in the large helical device deuterium plasma experiments. The gain and angular characteristics of the middle Sci-Fi detector were evaluated in an accelerator-based deuterium-tritium neutron source in the intense 14 MeV neutron source facility at Osaka University. Observation of 1 MeV triton transport due to MHD instability was performed by a middle Sci-Fi detector whose deuterium-tritium neutron counting rate was approximately 20 times higher than that of the conventional Sci-Fi detector. Fusion-born triton transport due to energetic-particle-driven MHD instability was observed using the middle Sci-Fi detector due to its high detection efficiency and high discrimination ability of deuterium-tritium neutrons from the sea of deuterium-deuterium neutrons.

scholarly journals Status of the two-dimensional, multi-wire proportional chamber detector for the China Spallation Neutron Source

2018 ◽  
Vol 48 ◽  
pp. 1860121 ◽  
Author(s):  
Zhiwen Wen ◽  
Huirong Qi
Keyword(s):  
Neutron Source ◽  
Neutron Detector ◽  
Detection Efficiency ◽  
Spallation Neutron Source ◽  
Two Dimensional ◽  
Large Area ◽  
Position Resolution ◽  
Proportional Chamber ◽  
High Detection Efficiency ◽  
Under Construction

The re-designed two-dimensional, multi-wire proportional chamber (MWPC) detector based on the [Formula: see text]He operation gas has been developed for the multifunctional reflection spectrum detection requirements in China Spallation Neutron Source (CSNS), which is under construction in Guangdong province, China. This efficient thermal neutron detector with large area (200 mm [Formula: see text] 200 mm active area), two-dimensional position sensitive (<2 mm of position resolution), high detection efficiency (>65% in the wavelength of 1.8Å) and good n/[Formula: see text] discrimination would meet some requirements in CSNS The neutron detector consists of a MWPC detector and a high-pressure gas vessel. The wire readout structures of the detector and the gas purity device have been optimized based on previous design and testing. The re-designed MWPC detector with an absorber thickness of 10 mm and 8.5 atm operating gas mixture of [Formula: see text]He and C[Formula: see text]H[Formula: see text] was constructed. Using the non-return valve manufactured by Swagelok, the gas purity device was developed to clean the water and remove gas impurities. The effective cycle time can be up to 50 min per sequence. The performance of the position resolution and the two-dimensional imaging accuracy by the traditional center of gravity readout method was studied with an X-ray radiation source and the neutron source. At the end of this year, the detector will be mounted at CSNS and studied using the neutron source.

scholarly journals Comparison of flux gradient and chamber techniques to measure soil N<sub>2</sub>O emissions

2018 ◽  
Author(s):  
Mei Bai ◽  
Helen Suter ◽  
Shu Kee Lam ◽  
Thomas K. Flesch ◽  
Deli Chen
Keyword(s):  
Measurement Techniques ◽  
N2o Emission ◽  
Chicken Manure ◽  
High Temporal Resolution ◽  
N2o Emissions ◽  
Emission Rates ◽  
Flux Gradient ◽  
Large Measurement ◽  
Slant Path ◽  
Vegetable Farm

Abstract. Improving the direct field measurement techniques to quantify gases emissions from the large agriculture farm is challenging. We compared nitrous oxide (N2O) emissions measured with static chambers to those from a newly developed micrometeorological flux gradient (FG) approach. Measurements were made at a vegetable farm following chicken manure application. The FG calculations were made with a single open-path Fourier transform infrared (OP-FTIR) spectrometer (height of 1.45 m) deployed in a slant-path configuration: sequentially aimed at retro reflectors at heights of 0.8 and 1.8 m above ground. Hourly emissions were measured with the FG technique, but once a day between 10:00 and 13:00 with chambers. We compared the concurrent emission ratios (FG/Chambers) between these two techniques, and found N2O emission rates from celery crop farm measured at mid-day by FG were statistically higher (1.4 times) than those from the chambers measured at the same time. Our results suggest the OP-FTIR slant-path FG configuration worked well in this study: it was sufficiently sensitive to detect the N2O gradients over our site, giving high temporal resolution N2O emissions corresponding to a large measurement footprint.

Pre-saddle and pre-scission neutron emission rates in heavy-ion induced fission of 16O +208Pb and 16O +209Bi systems

2019 ◽  
Vol 28 (03) ◽  
pp. 1950013
Author(s):  
Saeed Soheyli ◽  
Morteza Khalil Khalili ◽  
Ghazaaleh Ashrafi
Keyword(s):  
Emission Rate ◽  
Neutron Emission ◽  
Nonlinear Behavior ◽  
Heavy Ion ◽  
Neutron Multiplicity ◽  
Emission Rates ◽  
Reaction Systems ◽  
Initial Excitation ◽  
Induced Fission ◽  
First Time

Whereas there is a slight information on the pre-saddle neutron emission rate and neutron multiplicity, as well as it is impossible to separate the pre-saddle and saddle to scission neutron contributions experimentally, the theoretical studies of pre-saddle neutron emission rate and neutron multiplicity are of great importance. In the present work, the calculations of pre-saddle neutron multiplicity are performed using the analysis of fission fragment angular anisotropy data for [Formula: see text] and [Formula: see text] reaction systems. The obtained results show that the pre-saddle neutron multiplicity decreases by increasing the initial excitation energy and it has found to be characterized by a nonlinear behavior. Through the analysis of pre-saddle neutron multiplicity and pre-saddle transition time by means of the neutron clock method, the pre-saddle neutron emission rate is calculated for the first time. The findings of this study show that the pre-scission neutron emission rate is lower than the pre-saddle neutron emission rate.

scholarly journals Performance assessment of amplification and discrimination electronic devices for passive neutron measurements

2020 ◽  
Vol 225 ◽  
pp. 05001
Author(s):  
M. Ben Mosbah ◽  
C. Eleon ◽  
C. Passard ◽  
J. Loridon ◽  
B. Perot ◽  
...  
Keyword(s):  
Performance Assessment ◽  
Detection Efficiency ◽  
Electric Pulse ◽  
Measurement Techniques ◽  
Nuclear Industry ◽  
Fissile Material ◽  
High Count ◽  
Precision Data ◽  
Neutron Measurement ◽  
Current Amplifier

The knowledge of the fissile material mass is a key challenge to enhance radioactive waste management and to ensure a high level of safety in nuclear industry. Data is analyzed according to the principles of the neutron measurement techniques. As proportional counters filled with 3He gas display high neutron detection efficiency and a good gamma-ray discrimination, they are the reference detector for passive neutron coincidence counting. A charge preamplifier or a current amplifier, depending on applications, collects the electric pulse produced by neutron interaction in the 3He gas and a threshold discriminator produces a logic pulse used for neutron counting. This paper describes the performance assessment of different commercially available electronics from Mirion Technologies, Precision Data Technology (PDT), Mesytec, as well as MONACO electronics originally developed by CEA LIST for fission chamber measurements in experimental reactors. Comparative passive neutron measurements are carried out with these electronics at CEA/DEN Nuclear Measurement Laboratory in Cadarache. Overall, PDT and Mesytec electronics show similar detection efficiency as the ACH-NA98 charge amplifier, which is commonly used in our laboratory for such applications. However, MONACO electronics have a lower detection efficiency, similar to Mirion 7820 current amplifier used in specific high-count rate applications. An optimisation of MONACO settings would probably be necessary to adapt to 3He counters instead of fission chambers.

scholarly journals Measurement and simulation of the neutron detection efficiency with a Pb-scintillating fiber calorimeter

2009 ◽  
Vol 160 ◽  
pp. 012023 ◽  
Author(s):  
M Anelli ◽  
G Battistoni ◽  
S Bertolucci ◽  
C Bini ◽  
P Branchini ◽  
...  
Keyword(s):  
Detection Efficiency ◽  
Neutron Detection ◽  
Neutron Detection Efficiency ◽  
Scintillating Fiber

scholarly journals Central Deuteron Temperature Derived from Total Neutron Emission Rate in Electron Cyclotron Heated LHD Plasmas

2017 ◽  
Vol 12 (0) ◽  
pp. 1202036-1202036 ◽  
Author(s):  
Kunihiro OGAWA ◽  
Mitsutaka ISOBE ◽  
Takeo NISHITANI ◽  
Hiroki KAWASE ◽  
Neng PU ◽  
...  
Keyword(s):  
Emission Rate ◽  
Neutron Emission ◽  
Electron Cyclotron ◽  
Total Neutron
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