A Thermal Neutron Velocity Selector and Its Application to the Measurement of the Cross Section of Boron

Fermi, E.; Marshall, J.; Marshall, L.

doi:10.1103/physrev.72.193

Cited by 70 publications

(8 citation statements)

References 6 publications

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“…[ 6 ]), as well as epithermal neutrons. It is then pulsed using a “Fermi chopper” [ 2 ]. This is a device which spins about a vertical axis (normal to the direction of the beam), and is fitted with a set of curved slots.…”

Section: Time-of-flight Instruments At the Cold Neutron Research Fmentioning

confidence: 99%

“…In 1935, only 3 years after the discovery of the neutron, a pair of rotating disks was used to “prove by direct measurement that many of the slow neutrons [from a moderated Rn-Be source] are in the thermal velocity range” [ 1 ]. With the advent of the nuclear reactor (in 1942), more difficult measurements became possible, and a very different type of chopper was used by Enrico Fermi and his collaborators to determine the energy dependence of the absorption cross section of boron [ 2 ]. By 1960 relatively sophisticated phased chopper machines were being used to measure the scattering properties of materials such as water and polyethylene [ 3 ].…”

Section: Introductionmentioning

confidence: 99%

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Neutron time-of-flight spectroscopy

Copley¹,

Udovic²

1993

J. RES. NATL. INST. STAN.

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The time-of-flight technique is employed in two of the instruments at the NIST Cold Neutron Research Facility (CNRF). A pulsed monochromatic beam strikes the sample, and the energies of scattered neutrons are determined from their times-of-flight to an array of detectors. The time-of-flight method may be used in a variety of types of experiments such as studies of vibrational and magnetic excitations, tunneling spectroscopy, and quasielastic scattering studies of diffusional behavior; several examples of experiments are discussed. We also present brief descriptions of the CNRF time-of-flight instruments, including their modi operandi and some of their more pertinent parameters and performance characteristics.

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Section: Time-of-flight Instruments At the Cold Neutron Research Fmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Neutron time-of-flight spectroscopy

Copley¹,

Udovic²

1993

J. RES. NATL. INST. STAN.

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“…(Fermi 1952). In 1947 at Argonne National Laboratory, he built a chopper that bears his name to this day (Fermi et al 1947). Starting from the Fermi chopper, milestones in neuron chopper design included phased neutron scattering in the 1960s (Egelstaff 1965), pulsed neutron scattering in the '80s (Windsor 1981), and computational scattering science in the '90s (Fultz et al 2010).…”

Section: History and Operationmentioning

confidence: 99%

Advanced Manufacturing and Instrumentation for Neutron Chopper Design

Lu¹,

Sabharwall²,

Heidrich³

et al. 2020

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This review focuses on neutron choppers that deploy highspeed rotation (up to 500 Hz) and generate substantial heat and stress. After over 80 years of research and development, this instrumentation has reached a state of optimization, and engineers expect new research channels to overcome the historical limitations of only making incremental improvements (Crawford 2000). This study explores advanced manufacturing for neutron chopper design. Advanced manufacturing is to improve products and processes with the rapid transfer of modern techniques enabled by Information Communication Technology (PCAST 2010). The work aims to select neutron-absorbing material and designing chopperblade structure with phase changing fluid to effectively filter neutron beams and reduce heat generated by chopper rotation. The remainder of this review highlights methods used for this survey, evaluates selected studies in four categories, and discusses conclusions. The first category of the selected studies on neutron chopper development shows a trend in modern design methods with computing. The second traces the origin of advanced manufacturing as an emerging technology to improve neutron chopper design. The third and fourth categories focus on the two key themes: effective cooling and stable structuring, respectively. Overall, this work provides energy researchers with a new means for generating pulsed uniform-energy neutron beams. It also attracts an undergraduate audience in diverse disciplines to pursue nuclear engineering. METHODS Literature reviews examine scholarly works on a topic using different methods. Meta-analysis, popular among health sci

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“…A Fermi chopper consists of a rotating slit package to monochromatize neutron beam [36]. We developed a Fermi chopper (Figure 16a) [37] by using a magnetic bearing mounted in a turbo molecular pump whose pumping speed is 1300 L/s, because the mass and the moment of inertia of its rotor blade are almost identical to those of the slit package of the Fermi chopper.…”

Section: Fermi Choppersmentioning

confidence: 99%

Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex III: Neutron Devices and Computational and Sample Environments

Sakasai

Satoh

Seya

et al. 2017

QuBS

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Neutron devices such as neutron detectors, optical devices including supermirror devices and 3 He neutron spin filters, and choppers are successfully developed and installed at the Materials Life Science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC), Tokai, Japan. Four software components of MLF computational environment, instrument control, data acquisition, data analysis, and a database, have been developed and equipped at MLF. MLF also provides a wide variety of sample environment options including high and low temperatures, high magnetic fields, and high pressures. This paper describes the current status of neutron devices, computational and sample environments at MLF.

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A Thermal Neutron Velocity Selector and Its Application to the Measurement of the Cross Section of Boron

Cited by 70 publications

References 6 publications

Neutron time-of-flight spectroscopy

Neutron time-of-flight spectroscopy

Advanced Manufacturing and Instrumentation for Neutron Chopper Design

Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex III: Neutron Devices and Computational and Sample Environments

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