Design of the Moderator and Cryogenic System for Generating Cold-Neutrons at the CPHS

2010 ◽  
Author(s):  
Qixi Feng ◽  
Quanke Feng ◽  
Bin Zhong ◽  
Tianjiao Liang ◽  
Takeshi Kawai ◽  
...  
Keyword(s):  
Neutron Source ◽  
Cold Neutron ◽  
Cryogenic System ◽  
Good Resolution ◽  
Neutron Generation ◽  
Design And Optimization ◽  
Cold Neutrons ◽  
Operation Conditions ◽  
Characterization Of Materials ◽  
Soft Matters

The Compact Pulsed Hadron Source (CPHS) of Tsinghua University will produce neutrons by the Be(n,p) reaction through bombarding a proton beam with 13MeV/50Hz/1.25mA from a LINAC system on a beryllium target. One of the purposes of this neutron source facility is to provide the neutron scattering capability for characterization of materials, especially soft matters and biological systems. Cold neutrons (wavelength > 4 Å) are essential to characterize the structure of these materials over the length scale of ∼100 nm with good resolution. We discuss the design and optimization of a cold neutron source (CNS) which employs a solid methane moderator for cold neutron generation. The moderator configuration, the associated cryogenic system, and operation conditions will be discussed.

scholarly journals Cryogenic design for a high intensity ultracold neutron source at TRIUMF

2019 ◽  
Vol 219 ◽  
pp. 10001
Author(s):  
Shinsuke Kawasaki ◽  
Takahiro Okamura ◽  
Keyword(s):  
Heat Transport ◽  
Neutron Source ◽  
Superfluid Helium ◽  
High Intensity ◽  
Cold Neutron ◽  
Spallation Neutron Source ◽  
Cold Neutrons ◽  
Kapitza Conductance ◽  
Neutron Converter ◽  
Ultra Cold Neutron

The TUCAN (TRIUMF Ultra-Cold Advanced Neutron) collaboration has been developing a source of high-intensity ultra-cold neutrons for use in a neutron electric dipole search. The source is composed of a spallation neutron source and a superfluid helium ultra-cold neutron converter, surrounded by a cold moderator. The temperature of the superfluid helium needs to be maintained at approximately 1.0 K to suppress up-scattering by phonons. The Kapitza conductance and the heat transport by the superfluid helium are key parameters which need to be well characterized. We have therefore investigated them in first experiments. Current efforts are directed at optimizing the design of the helium cryostat.

Operation of a superthermal ultra-cold neutron source and the storage of ultra-cold neutrons in superfluid Helium4

1983 ◽  
Vol 51 (3) ◽  
pp. 187-193 ◽  
Author(s):  
R. Golub ◽  
C. Jewell ◽  
P. Ageron ◽  
W. Mampe ◽  
B. Heckel ◽  
...  
Keyword(s):  
Neutron Source ◽  
Cold Neutron ◽  
Cold Neutrons ◽  
Cold Neutron Source ◽  
Ultra Cold Neutron

scholarly journals Slab geometry type cold neutron moderator development based on neutronic study for Riken Accelerator-driven compact Neutron Source (RANS)

2020 ◽  
Vol 231 ◽  
pp. 04004
Author(s):  
Baolong Ma ◽  
Yujiro Ikeda ◽  
Yoshie Otake ◽  
Makoto Teshigawara ◽  
Yasuo Wakabayashi ◽  
...  
Keyword(s):  
Neutron Source ◽  
Room Temperature ◽  
Cold Neutron ◽  
High Energy ◽  
Material Research ◽  
Slab Geometry ◽  
Simulation Code ◽  
Cold Neutrons ◽  
Neutron Moderator ◽  
Pulsed Neutron

Cold neutrons with energy less than several meV are good probes for material research, and they have been available on large neutron facilities, whereas it is not commonly available on compact accelerator-driven neutron source. RIKEN Accelerator-driven Neutron Source (RANS) is a pulsed neutron facility which provides thermal neutrons and high energy neutrons at several MeV. We started a project to implement a cold neutron moderator for RANS to broaden cold neutrons applications. A cold neutron moderator system with a mesitylene moderator at 20K and a polyethylene pre-moderator at room temperature in the slab geometry was designed for RANS. So far, the thickness of the pre-moderator and mesitylene have been optimized to get the highest cold neutron flux by using a Monte Carlo simulation code, PHITS. Graphite reflector dimensions were also proven to have significant effect to increase the cold neutron intensity.

Characterization of Materials for a Hydrogen-Based Economy by Cold Neutron Prompt Gamma-Ray Activation Analysis

2008 ◽  
Vol 1098 ◽  
Author(s):  
Rick Paul ◽  
Lei Raymond Cao
Keyword(s):  
Activation Analysis ◽  
Hydrogen Storage ◽  
Gamma Ray ◽  
Cold Neutron ◽  
Proton Conductors ◽  
Prompt Gamma ◽  
Hydrogen Storage Materials ◽  
Storage Materials ◽  
Characterization Of Materials

AbstractAn instrument for cold neutron prompt gamma-ray activation analysis (PGAA) at the NIST Center for Neutron Research (NCNR) has proven useful for the chemical characterization of hydrogen storage materials and other materials of importance to a hydrogen-based economy. The detection limit for hydrogen is less than 10 mg/kg for most materials. Potential hydrogen storage materials that have been characterized by PGAA include single-wall carbon nanotubes with and without boron doping, porous carbons, lithium magnesium imides, and ternary hydrides of various elements. The capability to allow in situ hydrogenation and characterization of materials is currently under development. PGAA has also been used to characterize materials used in hydrogen fuel cells, including solid proton conductors, polymer membrane, and proton exchange membranes. Future upgrades to the instrument will improve detection limits and functionality of the instrument.

scholarly journals Confirmation of Nuclear Heating Rate for Installation of Cold Neutron Source at HANARO

2020 ◽  
Vol 225 ◽  
pp. 04004
Author(s):  
Kim Myong-Seop ◽  
Park Byung-Gun
Keyword(s):  
Heating Rate ◽  
Neutron Source ◽  
Cold Neutron ◽  
Reactor Core ◽  
Reactor Power ◽  
Electric Heater ◽  
Lead Wire ◽  
Heating Rates ◽  
Cold Neutron Source ◽  
Nuclear Heating

In order to determine the capacity of the cold neutron source refrigerator of HANARO, the nuclear heating rate at CN vertical hole is measured by using the heat-flow calorimetric method and confirmed by the calculation. The heating rate measurement device of HANARO was composed of a calorimeter sensor, an air containing aluminum sleeve for fitting the sensor to the CN hole, aluminum weight and a lead wire assembly. The calorimeter sensor consists of a cylindrical Al sample and container, two thermocouples and the electric heater for the calibration of the calorimeter. The sample is separated by an air gap from the Al container surrounded by an air containing Al sleeve. After installation of the calorimeter at a measurement position of HANARO, the heat transfer inside the calorimeter was simulated by the electric heating for the sample. The nuclear heating rates at the CN hole were determined at three reactor powers of 1, 4 and 8 MW by using the calibration curve and the temperature measurements at each reactor power. The measured nuclear heating rate per unit mass of Al sample at 8 MW reactor power is 0.143 W/g and it is equivalent to the 0.494 W/g at 30 MW. The nuclear heating rate was calculated by using the MCNP code. The calculation model for the whole facility including the reactor core and the reflector tank were established. In the calculation procedure, the heat generations by various radiations were evaluated with considering the prompt, delayed and activation effects. The measured heating rate was reasonably well supported by the calculation using the cold neutron facility design code. It will be very useful for the moderator cell of cold neutron source of HANARO.

scholarly journals The new cold neutron chopper spectrometer at the Spallation Neutron Source: Design and performance

2011 ◽  
Vol 82 (8) ◽  
pp. 085108 ◽  
Author(s):  
G. Ehlers ◽  
A. A. Podlesnyak ◽  
J. L. Niedziela ◽  
E. B. Iverson ◽  
P. E. Sokol
Keyword(s):  
Neutron Source ◽  
Cold Neutron ◽  
Spallation Neutron Source ◽  
And Performance

Physics study of liquid hydrogen moderator of CMRR reactor cold neutron source

2019 ◽  
Vol 110 ◽  
pp. 121-128
Author(s):  
Longwei Mei ◽  
Cong Liu ◽  
Songlin Wang ◽  
Fei Shen
Keyword(s):  
Neutron Source ◽  
Cold Neutron ◽  
Liquid Hydrogen ◽  
Cold Neutron Source

CFD Simulations of the Cold Neutron Source at the OPAL Reactor

2020 ◽  
Author(s):  
James L Spedding ◽  
Mark Ho ◽  
Weijian Lu
Keyword(s):  
Neutron Source ◽  
Cold Neutron ◽  
Operating Conditions ◽  
Convergence Time ◽  
Cfd Model ◽  
Cfd Simulations ◽  
Cold Neutron Source ◽  
Order Of Magnitude ◽  
Computational Fluid Dynamics Cfd ◽  
Polyhedral Mesh

Abstract The Open Pool Australian Light-water (OPAL) reactor Cold Neutron Source (CNS) is a 20 L liquid deuterium thermosiphon system which has performed consistently but will require replacement in the future. The CNS deuterium exploits neutronic heating to passively drive the thermosiphon loop and is cryogenically cooled by forced convective helium flow via a heat exchanger. In this study, a detailed computational fluid dynamics (CFD) model of the complete thermosiphon system was developed for simulation. Unlike previous studies, the simulation employed a novel polyhedral mesh technique. Results demonstrated that the polyhedral technique reduced simulation computational requirements and convergence time by an order of magnitude while predicting thermosiphon performance to within 1% accuracy when compared with prototype experiments. The simulation model was extrapolated to OPAL operating conditions and confirmed the versatility of the CFD model as an engineering design and preventative maintenance tool. Finally, simulations were performed on a proposed second-generation CNS design that increases the CNS moderator deuterium volume by 5 L, and results confirmed that the geometry maintains the thermosiphon deuterium in the liquid state and satisfies the CNS design criteria.

scholarly journals Proof-of-principle experiment for laser-driven cold neutron source

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
S. R. Mirfayzi ◽  
A. Yogo ◽  
Z. Lan ◽  
T. Ishimoto ◽  
A. Iwamoto ◽  
...  
Keyword(s):  
Neutron Source ◽  
Cold Neutron ◽  
High Repetition Rate ◽  
Pure Hydrogen ◽  
High Brightness ◽  
Monte Carlo Techniques ◽  
Exit Surface ◽  
Wide Range ◽  
Cold Neutron Source ◽  
Technical Advances

AbstractThe scientific and technical advances continue to support novel discoveries by allowing scientists to acquire new insights into the structure and properties of matter using new tools and sources. Notably, neutrons are among the most valuable sources in providing such a capability. At the Institute of Laser Engineering, Osaka, the first steps are taken towards the development of a table-top laser-driven neutron source, capable of producing a wide range of energies with high brightness and temporal resolution. By employing a pure hydrogen moderator, maintained at cryogenic temperature, a cold neutron ($$\le 25\hbox { meV}$$ ≤ 25 meV ) flux of $$\sim 2\times 10^3\hbox { n/cm}^2$$ ∼ 2 × 10 3 n/cm 2 /pulse was measured at the proximity of the moderator exit surface. The beam duration of hundreds of ns to tens of $$\upmu \hbox {s}$$ μ s is evaluated for neutron energies ranging from 100s keV down to meV via Monte-Carlo techniques. Presently, with the upcoming J-EPoCH high repetition rate laser at Osaka University, a cold neutron flux in orders of $$\sim 1\times 10^{9}\hbox { n/cm}^2/\hbox {s}$$ ∼ 1 × 10 9 n/cm 2 / s is expected to be delivered at the moderator in a compact beamline.

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