Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 100.00K | Year: 2008
Applied Pulsed Power, Inc. (APP) proposes to develop a solid state switch for high voltage sub-microsecond pulsed power, using silicon carbide devices. The objective of the solicitation is to develop a compact, solid state pulsed power switch capable of switching 20-50 kV, and I > 5 kA with low jitter, fast rise time (~20 ns), L < 20 nH, pulse length 100 to 1000 ns, and up to 1000 Hz prf. APP has developed and presently sells solid state switches capable of switching 20-50 kV, and I > 5 kA with low jitter, pulse length to 1000 ns, and up to 1000 Hz prf using silicon thyristors. These switches are used for applications with pulsewidths >200 ns and di/dt of
Agency: Department of Energy | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 99.80K | Year: 2001
65172 A high current, high brightness, 10 pulsor per second (pps) ion source is a key component of a heavy ion fusion accelerator. This project will use a high purity pulsed inductive, gas-breakdown plasma source to generate a plasma with a high directed velocity. The source is positioned a large distance from the accelerator, resulting in separation of neutral gas from the accelerator and collimation of the ions entering the accelerator. In Phase I, an experimental argon pulsed inductive plasma source will be fabricated and used to conduct initial research with available drivers and plasma diagnostics. Modifications to the plasma source will be made to obtain ion source parameters consistent with the requirements for standard accelerating structures, as determined from a preliminary injector stage design. Ultimately, Phase I will determine whether the pulsed inductive plasma source can produce desired ion source characteristics for a heavy ion fusion induction linac. Commercial Applications And Other Benefits as described by awardee: Commercial applications of pulsed inductive plasma sources include plasma and ion beam processing and plasma propulsion schemes. Ion sources should also have applications to other fusion power approaches, including high flux neutral beams and plasmoids for injection into magnetically confined plasmas and field reversed ion rings.
Applied Pulsed Power Inc. | Date: 2011-05-19
An optically triggered semiconductor switch includes an anode metallization layer; a cathode metallization layer; a semiconductor between the anode metallization layer and the cathode metallization layer and a photon source. The semiconductor includes at least four layers of alternating doping in the form P-N-P-N, in which an outer layer adjacent to the anode metallization layer forms an anode and an outer layer adjacent the cathode metallization layer forms a cathode and in which the anode metallization layer has a window pattern of optically transparent material exposing the anode layer to light. The photon source emits light having a wavelength, with the light from the photon source being configured to match the window pattern of the anode metallization layer.
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase II | Award Amount: 748.40K | Year: 2009
ABSTRACT: Applied Pulsed Power, Inc. (APP) proposes to develop a solid state switch for high voltage sub-microsecond pulsed power, using silicon carbide modules. The objective of the solicitation is to develop a compact, solid state pulsed power switch capable of switching 20-50 kV, and I > 5 kA with low jitter, fast rise time (~20 ns), L < 20 nH, pulse length 100 to 1000 ns, and up to 1000 Hz prf. APP has developed and presently sells solid state switches capable of switching 20-50 kV, and I > 5 kA with low jitter, pulse length to 1000 ns, and up to 1000 Hz prf using silicon thyristors.[1,2] These switches are used for applications with pulsewidths > 200 ns and di/dt of < 100 kA/us. Patented packaging and triggering techniques are used to produce 20-60 kV switches from multiple identical lower voltage modules.[3,4,5] APP is also developing laser triggered, fast turn on, silicon switches. We will apply these techniques to silicon carbide devices to produce low inductance (< 1nH/kV) switches with
Weinberg I.N.,Weinberg Medical Physics LLC |
Stepanov P.Y.,Weinberg Medical Physics LLC |
Fricke S.T.,Childrens National Medical Center |
Probst R.,Weinberg Medical Physics LLC |
And 7 more authors.
Medical Physics | Year: 2012
Purpose: A time-varying magnetic field can cause unpleasant peripheral nerve stimulation (PNS) when the maximum excursion of the magnetic field (ΔB) is above a frequency-dependent threshold level P. Mansfield and P. R. Harvey, Magn. Reson. Med. 29, 746-758 (1993). Clinical and research magnetic resonance imaging (MRI) gradient systems have been designed to avoid such bioeffects by adhering to regulations and guidelines established on the basis of clinical trials. Those trials, generally employing sinusoidal waveforms, tested human responses to magnetic fields at frequencies between 0.5 and 10 kHz W. Irnich and F. Schmitt, Magn. Reson. Med. 33, 619-623 (1995), T. F. Budinger, J. Comput. Assist. Tomogr. 15, 909-914 (1991), and D. J. Schaefer, J. Magn. Reson. Imaging 12, 20-29 (2000). PNS thresholds for frequencies higher than 10 kHz had been extrapolated, using physiological models J. P. Reilly, IEEE Trans. Biomed. Eng. BME-32(12), 1001-1011 (1985). The present study provides experimental data on human PNS thresholds to oscillating magnetic field stimulation from 2 to 183 kHz. Sinusoidal waveforms were employed for several reasons: (1) to facilitate comparison with earlier reports that used sine waves, (2) because prior designers of fast gradient hardware for generalized waveforms (e.g., including trapezoidal pulses) have employed quarter-sine-wave resonant circuits to reduce the rise- and fall-times of pulse waveforms, and (3) because sinusoids are often used in fast pulse sequences (e.g., spiral scans) S. Nowak, U.S. patent 5,245,287 (14 September 1993) and K. F. King and D. J. Schaefer, J. Magn. Reson. Imaging 12, 164-170 (2000). Methods: An IRB-approved prospective clinical trial was performed, involving 26 adults, in which one wrist was exposed to decaying sinusoidal magnetic field pulses at frequencies from 2 to 183 kHz and amplitudes up to 0.4 T. Sham exposures (i.e., with no magnetic fields) were applied to all subjects. Results: For 0.4 T pulses at 2, 25, 59, 101, and 183 kHz, stimulation was reported by 22 (84.6), 24 (92.3), 15 (57.7), 2 (7.7), and 1 (3.8) subjects, respectively. Conclusions: The probability of PNS due to brief biphasic time-varying sinusoidal magnetic fields with magnetic excursions up to 0.4 T is shown to decrease significantly at and above 101 kHz. This phenomenon may have particular uses in dynamic scenarios (e.g., cardiac imaging) and in studying processes with short decay times (e.g., electron paramagnetic resonance imaging, bone and solids imaging). The study suggests the possibility of new designs for human and preclinical MRI systems that may be useful in clinical practice and scientific research. © 2012 American Association of Physicists in Medicine.