Intense Pulsed Source Research Articles

Quasi-Isentropic Compressibility of Deuterium at a Pressure of ~12 TPa

An experimental result for the quasi-isentropic compressibility of a strongly nonideal deuterium plasma compressed in a spherical device by the pressure P = 11400 GPa (114 Mbar) to the density ρ ≈ 10g/cm3 has been reported. The characteristics of the experimental device, diagnostic methods, and experimental results have been described. The trajectory of motion of metallic shells compressing a deuterium plasma has been recorded using intense pulsed sources of X rays with the boundary energy of electrons up to 60 MeV. The deuterium plasma density ρ ≈ 10g/cm3 has been determined from the measured radius of the shell at the time of its “stop.” The pressure of the compressed plasma has been determined from gas-dynamic calculations taking into account the real characteristics of the experimental device.

RED-100 detector for the first observation of the elastic coherent neutrino scattering off xenon nuclei

The RED-100 (Russian Emission Detector) is being constructed for the experiment to search for elastic coherent neutrino scattering off atomic nuclei. This fundamental process was predicted several decades ago by the Standard Model of electroweak interactions but has not been discovered yet. The RED-100 is a two-phase emission xenon detector containing ∼200 kg of the liquid Xe (∼ 100 kg of that is in a fiducial volume). One of the possible sites to carry out the experiment is the SNS (Spallation Neutron Source) facility at Oak Ridge National Laboratory, USA. SNS is the world's most intense pulsed source of neutrinos and unique place to study neutrino properties. The energy spectrum of neutrinos produced at the SNS extends up to ∼ 50 MeV and satisfies coherence condition. These neutrinos give kinetic energies of Xe recoils up to a few tens of keV where the response of nuclear recoils is well-known from neutron calibrations of dark matter detectors. The detector will be deployed in the basement under the experimental hall at a distance of ∼30 meters from the SNS target. The expected signal and background (neutron and gamma) are estimated for this specific location. The detector details, current status and future plans are provided.

Response of lithographic mask structures of intense repetitively pulsed x rays: Thermal stress analysis

This paper examines the effects of thermal loading and time history upon the thermal stresses developed in lithographic mask structures as would be expected under irradiation by intense soft x rays. The objective of this work was to examine the phenomenology of the interaction and to evaluate the limits placed upon mask dosage. The mechanics of mask failure are examined in terms of single pulse and cumulative, or fatigue, effects. A number of prototypical mask structures are investigated, which show that the application of intense pulsed sources to x-ray lithography does not reduce the potential utility of the techique. However, it is shown that the estimated damage thresholds do impact the operating conditions chosen for optimal production rates and mask lifetime.

Multiple Uses of an Upgraded FMIT Facility

The Fusion Materials Irradiation Test (FMIT) facility was designed to test small samples in fluxes greater than 1015) n cm2-s of fusion-like neutrons. The source of neutrons would be a 0.1 A beam of 35 MeV deuterons stopped in a liquid lithium jet target. During the present construction deferral, pending an international agreement, an expanded mission is being explored. Multiple CW beams in a common accelerator structure could be used to obtain a total steady-state beam current of about 1 A. This could provide for simultaneous multiple uses in up to four or more target areas as described below. For fusion materials, individual CW beams could be simultaneously directed to two or more FMIT targets, greatly improving availability. Alternately, the multiple beams could be combined for testing of large, multi-liter sized components of fusion reactors. At the same time, research in condensed matter could be pursued using both a steady-state and pulsed source of thermal neutrons in separate target areas. A steady-state flux that is an order of magnitude improvement over current reactor sources can be obtained. Moreover, a pulsed source that is comparable to the most intense pulsed sources nearing completion can also be achieved.

Maximum Density and Capture Rate of Neutrons Moderated from a Pulsed Source

We show that upper bounds exist on the density of neutrons that can be moderated to a specified energy from an intense pulsed source of fast neutrons. Expressions are derived for the maximum density in the following cases: (a) a uniform infection of fast neutrons into an infinite moderator, (b) a localized central source in a finite heavy atom moderator, and (c) a point source in an infinite hydrogenous moderator. Correspondingly, upper bounds are given for the rates of single- and multiple-resonance neutron capture.

A Magnetic Compton Spectrometer for High Intensity Pulsed Gamma Ray Environments

A magnetic Compton spectrometer is described which was designed to measure the gamma ray spectra from distributed, intense pulsed sources in the presence of gama ray, electron, and/or neutron backgrounds. It has been used to measure spectra of a nuclear device, the Sandia Pulsed Reactor, and the Hermes II flash x-ray machine. A discussion will be given of the design features, the data reduction, and the results of the Hermes II measurement.