Pulsed Facility Research Articles

Exploitation of a Pulsed Laser to Explore Transient Effects on Semiconductor Devices

This paper sets out to demonstrate the use of a pulsed semiconductor laser facility as a laboratory prompt gamma simulator, to complement existing radiation simulators. Comparability has been established between results obtained on the Laser Simulator and LINAC on a device technology family basis. The ease with which measurements at elevated temperatures and small area searches can be made are addressed and limitations to its use are noted.

A pulsed surface muon beam andμSR facilities proposed for the UK

The Spallation Neutron Source, SNS, under construction in the United Kingdom offers the possibility of an intense pulsed pion or muon source and aμSR facility for condensed matter spectroscopy has been proposed.

Polarized neutron scattering using pulsed spallation neutron source at KEK

We present results of one years experience with the polarized neutron spectroscopy at the pulsed spallation neutron facility at KEK. We discuss the feasibility of a new method manipulating the dual time indicators of both pulses and neutron spin rotations.

Measurement of the particle size distribution in a pulsed hypersonicflow facility

Measurement of the particle size distribution in a pulsed hypersonicflow facility

A Low Jitter Triggered Gas Switch to Synchronize Modular Accelerators

Physics International (PI) has developed a high voltage, low jitter, command triggered gas switch to serve as an output switch for the slow-charging transfer capacitor in EAGLE, a 2 TW pulsed power research facility presently under construction. EAGLE is a prototype module of PI's conceptual design for a 40-50 TW, 4-5 MJ pulsed accelerator called ROULETTE (see Figure 1). The use of our triggered gas switch in ROULETTE provides distinct advantages over conventional water switches: considerably lower intermodule jitter, less ohmic dissipation, reduced mechanical shock loading of structures, and better control of the current distribution.

Neutron diffraction studies of liquid phosphorus

Neutron diffraction measurements of liquid phosphorus at 50°C have been made using both steady-rate (reactor) and pulsed (linac) neutron facilities. The high Q-value measurements have been used to characterize the molecular form factor and to study various inelasticity corrections. The low Q-value results are used to derive an intermolecular pair distribution function which shows strong orientational correlation effects and has significant oscillations extending up to 20 Å. The packing of the molecular units is different from that exhibited by the tetrachloride liquids and more closely resembles the structural arrangement observed in amorphous yellow arsenic.

Annular (HSURIA) resonators: some experimental studies including polarization effects

A repetitively pulsed CO(2) laser facility was developed for testing annular resonators. The large-aperture device exhibits generally uniform gain over an annular region of 18-cm o.d. and 10-cm i.d. The half-symmetric unstable resonator with internal axicon (HSURIA) was tested at equivalent Fresnel numbers up to 4.5. This resonator design incorporates a W-axicon mirror beam compactor that transforms a cylindricalmode region into an annular-mode region. Two HSURIA configurations were evaluated: (a) with a conical end mirror and (b) with a flat end mirror in the annular leg. With the conical end mirror, the aligned resonator produced a predominantly higher-order azimuthal mode with an on-axis null in the far field. The output was strongly linearly polarized with the electric-field vector tangential to the optic axis in both the near and far fields. The higher-order tangentially polarized mode appears to be the result of a geometric polarization scrambling effect caused by the conical end mirror. The boundary conitions for the conical or W-axicon mirrors imply that the radial electric field has a 180 degrees phase shift on reflection, whereas the tangential component is unchanged. Thus, a tangentially polarized mode is self-reproducing, but a linearly polarized mode is not. To eliminate the polarization scrambling effect in the HSURIA, the conical end mirror was replaced with a flat end mirror. The HSURIA with a flat end mirror produced a central spot in the far field that indicated an l = 0 mode with no spatial variations in polarization. Beam quality was measured in terms of the ratio n(2) of the theoretical (geometric-mode) power transmitted through an aperture of the central lobe diameter to the observed power; n(2) values as low as 1.2 were obtained. The variation of beam quality with tilt of the flat end mirror indicated a factor of 2 degradation in n(2) for a 20-microrad tilt, which is in good agreement with theory.

An ultrasonic real-time scanner with pulsed doppler and T- M facilities for foetal breathing and other obstetrical studies

An ultrasonic system for foetal breathing studies is described. The system is composed of a Real-Time scanner with T- M mode and pulsed Doppler facilities. Possible approaches to Real-Time Scanning for studying foetal breathing are reviewed. Reasons for employing a rotating transducer scanner of small dimensions are presented. The roles of the three ultrasonic facilities, i.e. Real-Time, T- M and Doppler techniques are discussed. Finally the requirements of an ultrasonic system for studying foetal breathing are identified. Future developments and applications of the system are indicated.

Panel recommends pulsed high‐flux neutron facility

The creation of a national high‐flux pulsed spallation neutron facility is one of the major recommendations of the Panel on Research Facilities and Scientific Opportunities in the Use of Low Energy Neutrons. The panel was established in early 1977 by the Solid State Sciences Committee of the Assembly of Mathematical and Physical Sciences, National Academy of Sciences‐National Research Council. Gordon K. Teal, formerly chief scientist at Texas Instruments, served as chairman and Clifford G. Shull of MIT was vice‐chairman.

Timing experiments and burst suppression at the V.U. AVF-cyclotron

The pulsed beam facility at the AVF-cylotron of the Vrije Universiteit is presented. The possibilities of the pulsed beam for lifetime measurements, g-factor determination and investigation of the cyclotron beam behaviour are discussed.

Laser solenoid radiation test facility

The Laser Solenoid Radiation Test Facility (LSRTF) is a concept based on a pulsed plasma source of neutrons, alpha particles, and bremsstrahlung and is characterized by a moderate radiation flux and a large test sample volume. The LSRTF is intermediate in its size, technology, and availability (1985–1990), and consequently has potential for bridging the gap between small present day accelerator-target sources and a large pulsed plasma engineering research facility in the 1990's. It also has important potential as a compact engineering test reactor for realistic operational testing of integrated subsystems for a linear fusion reactor. Its design, performance, and operating characteristics are discussed in the present paper. The necessary development programs to bring such a facility into timely operation are also described.

The structure factor for liquid bromine by neutron diffraction

Thermal neutrons from steady-state (reactor) and pulsed (linac) neutron facilities have been used to study the structure factor for liquid bromine at 20°C, covering a wide range of values (0·6-35 A-1) of the momentum transfer (ħQ). The diffraction pattern at high Q-values (>10 A-1) gives information on the structural properties of the individual molecules but detailed interpretation is complicated by the vibrational motion which causes a systematic variation in the periodic oscillations of the molecular form-factor. An internuclear distance (bond length) of 2·28 ± 0·01 A is found to be suitable for data at lower Q-values and has been used in the analysis of the liquid structure. The results show that some form of orientational correlation between molecules must be present and the nuclear (atom) pair correlation function is split into two peaks for the coordination shell corresponding to nearest-neighbour molecules. The results are compared with other studies of liquid bromine and similar neutron experimen...

Charged particle mass identification by energy-time-of-flight technique

The energy-time-of-flight technique for charged particle mass identification has been succesfully used in the mass range from mass 1 to 12 and in the energy range from 0.5 MeV to 11 MeV. As an illustration of the usefulness of the technique, the results of the analysis of the reactions produced by 12C nuclei bombarded by deuterons at 12 MeV are presented. The pulsed and bunched beam facilities of the Rice University tandem Van de Graaff were used, and particles resulting from the bombardment were detected with a silicon surface barrier solid state detector. The energy and time-of-flight parameters were processed using an IBM 1800 real time computer with an ADC resolution of 1024 channels for each parameter. Twenty-six energy peaks from the 12C(d, y)Y reaction were identified, while, for comparison, the free energy spectrum provides only ten peaks.

Z-pinch pulsed photolysis facility for investigating fast processes

Z-pinch pulsed photolysis facility for investigating fast processes

Signal Corps Studies of Nuclear Radiation Effects on Electronic Components and Materials

The U. S. Army Signal Research and Development Laboratory has long been interested in the effects of nuclear radiation on electronic components and materials. An historical account of USASRDL participation in earlier weapons tests is presented along with more recent efforts toward the evaluation of component operation during a burst of nuclear radiation using various pulsed reactor facilities. The radiation effects on some present-day components is briefly described, and possible directions of future efforts to develop radiation-resistant components and equipment are proposed.