arXiv subjects

A. Hecht

Publications and source records attributed to A. Hecht.

4 recordsLinked to original sources

arXiv2020

Oscillatory magnetic fields for neutron resonance spin-echo spectroscopy

The generation of high frequency oscillatory magnetic fields represents a fundamental component underlying the successful implementation of neutron resonant spin-echo spectrometers, a class of instrumentation critical for the high-resolution extraction of dynamical excitations (structural and magnetic) in materials. In this paper, the setup of the resonant circuits at the longitudinal resonant spin-echo spectrometer RESEDA is described in comprehensive technical detail. We demonstrate that these circuits are capable of functioning at frequencies up to 3.6 MHz and over a broad bandwidth down to 35 kHz using a combination of signal generators, amplifiers, impedance matching transformers, and a carefully designed cascade of tunable capacitors and customized coils.

cond-mat.str-el↗

arXiv2016

Cosmic ray muon computed tomography of spent nuclear fuel in dry storage casks

Radiography with cosmic ray muon scattering has proven to be a successful method of imaging nuclear material through heavy shielding. Of particular interest is monitoring dry storage casks for diversion of plutonium contained in spent reactor fuel. Using muon tracking detectors that surround a cylindrical cask, cosmic ray muon scattering can be simultaneously measured from all azimuthal angles, giving complete tomographic coverage of the cask interior. This paper describes the first application of filtered back projection algorithms, typically used in medical imaging, to cosmic ray muon imaging. The specific application to monitoring spent nuclear fuel in dry storage casks is investigated via GEANT4 simulations. With a cylindrical muon tracking detector surrounding a typical spent fuel cask, the cask contents can be confirmed with high confidence in less than two days exposure. Similar results can be obtained by moving a smaller detector to view the cask from multiple angles.

physics.ins-det↗

arXiv2014

Detecting Special Nuclear Material Using Muon-Induced Neutron Emission

The penetrating ability of cosmic ray muons makes them an attractive probe for imaging dense materials. Here, we describe experimental results from a new technique that uses neutrons generated by cosmic-ray muons to identify the presence of special nuclear material (SNM). Neutrons emitted from SNM are used to tag muon-induced fission events in actinides and laminography is used to form images of the stopping material. This technique allows the imaging of SNM-bearing objects tagged using muon tracking detectors located above or to the side of the objects, and may have potential applications in warhead verification scenarios. During the experiment described here we did not attempt to distinguish the type or grade of the SNM.

physics.ins-det↗

arXiv2007

From chiral vibration to static chirality in ^{135}Nd

Electromagnetic transition probabilities have been measured for the intra- and inter-band transitions in the two sequences in the nucleus ^{135}Nd that were previously identified as a composite chiral pair of rotational bands. The measurements are in good agreement with results of a new combination of TAC and RPA calculations. The chiral character of the bands is affirmed and it is shown that their behavior is associated with a transition from a vibrational into a static chiral regime.

nucl-ex↗