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Showing papers on "Rise time published in 1993"


Journal ArticleDOI
TL;DR: The observed “tuning” of the mechanical properties to the movement speed is suggested to be important in the robust generation of smooth stereotyped voluntary movements.
Abstract: The stiffness of the human elbow joint was investigated during targeted, 1.0-rad voluntary flexion movements at speeds ranging from slow (1.5 rad/s) to very fast (6.0 rad/s). A torque motor produced controlled step position errors in the execution of the movements. The steps began at the onset of movement, rose to an amplitude of 0.15 rad in 100 ms, and had a duration equal to movement duration. The net joint torque (muscle torque) resisting the step perturbation was computed from the applied torque, the joint acceleration, and the limb inertia. Subjects resisted the imposed step changes with approximately step changes in the net muscle torque. The mean resistance torque divided by the step amplitude was computed and is referred to as the stiffness. The stiffness increased with the voluntary movement speed, over the range of speeds (1.5–6 rad/s). The stiffness increased linearly with the magnitude of the net muscle torque on the unperturbed trials (referred to as “background torque”). The stiffness changed by only 20% when the step amplitude ranged from 0.05 to 0.15 rad. The mechanical resonant frequency (f r), estimated from the average stiffness estimates, ranged from 0.8 to 3.0 Hz. The resonant frequency approximately equaled the principal frequency component of the movement f m. On average: f r = 0.96 f m+0.46. During the fixed, 100-ms rise time of the step, the resistance was not linearly related to the background torque. At slower speeds the resistance was relatively greater during this rise time. However, when the imposed step perturbation was modified so that its rise time occurred in a time proportional to the movement duration (rather than in the fixed, 100-ms, time), the muscle torque resisting the motor during this rise time was proportional to the background torque. When these modified step responses were plotted on a time scale normalized to the movement duration, they all had approximately the same shape. Apparently the muscle viscosity scaled with the stiffness so as to maintain the constant response shape (constant damping ratio). The observed “tuning” of the mechanical properties to the movement speed is suggested to be important in the robust generation of smooth stereotyped voluntary movements.

131 citations


Journal ArticleDOI
TL;DR: In this article, an alternative model is derived, the limits of its accuracy are estimated, and a correction factor is described for large surges of short time duration, as they are encountered in present day power conditioning systems.
Abstract: Thermal response curves used to calculate the peak junction temperature of power semiconductors are normally derived by experimental identification of the parameters of a known model. Unfortunately the model, developed many years ago, is inappropriate for large surges of short time duration, as they are encountered in present day power conditioning systems. An alternative model is derived, the limits of its accuracy are estimated, and a correction factor is described. A verification of the accuracy of the two methods is also presented. For pulse widths shorter than the thermal transit time, which is in the order of 300 mu s, the peak junction temperature can be more accurately calculated with an expression derived in the present work, which takes into consideration the active volume in which the heat is generated, than with the transient thermal response curve. A correction factor, a function of the width of the pulse, inserted in this equation, further improves its accuracy. >

88 citations


Patent
Michika Uesugi1
02 Dec 1993
TL;DR: In this paper, the duty factor of the PWM pulse signal is reduced so as to be cut off after the overcurrent has been detected, without stopping the operation of the compressor and the compressor motor.
Abstract: In case an instantaneous over-current flowing through switching elements is detected between a predetermined rise time point and a predetermined fall time point of each of the PWM control pulses, the output of the duty control circuit is stopped immediately. In other words, the duty factor of the PWM pulse signal to be outputted as it is under the normal conditions is reduced so as to be cut off after the over-current has been detected. Therefore, it is possible to protect the switching elements of the inverter from breakdown due to over-current, without stopping the operation of the compressor and the compressor motor.

60 citations


Journal ArticleDOI
09 May 1993
TL;DR: In this article, the authors present generalized hot-carrier-reliability design rules that translate device-level degradation rate to CMOS circuit lifetime, and demonstrate that a circuit reliability simulator BERT can predict CMOS digital circuit speed degradation from transistor DC stress data.
Abstract: Long-term ring-oscillator hot-carrier degradation data and simulation results are compared to demonstrate that a circuit reliability simulator BERT can predict CMOS digital circuit speed degradation from transistor DC stress data. We present generalized hot-carrier-reliability design rules that translate device-level degradation rate to CMOS circuit lifetime. The design rules, which consist of lifetime and speed degradation factors, can roughly predict CMOS circuit degradation during the initial design, and can help reliability engineers to quickly estimate the overall product hot-carrier reliability. The NMOSFET and PMOSFET lifetime factors were found to obey 4/ft/sub rise/ and 10/ft/sub fall/ respectively. Typically, the NMOSFET and PMOSFET speed degradation factors are 1/4 and 1/2, respectively, with saturation region drain current as the monitor, while for a 100 MHz operating frequency and for an input rise time of 0.35 ns, the NMOSFET and PMOSFET time factors are 120 and 300, respectively. >

39 citations


Journal ArticleDOI
TL;DR: In this article, the displacement of a water-air interface and its relaxation as a function of acoustic energy density and surface tension were analyzed both experimentally and numerically, and a theoretical model to predict the response of the interface to acoustic excitation was also developed.
Abstract: The displacement of a water–air interface and its relaxation as a function of acoustic energy density and surface tension were analyzed both experimentally and numerically. Experimental systems were devised to observe the time evolution of the surface. A theoretical model to predict the response of the interface to acoustic excitation was also developed. It was found that the Langevin pressure due to a focused acoustic beam will cause the interface to rise to a height that is a function of the energy density of the beam. The rise time, which is the time it takes for the wafer surface to rise to its maximum height, was found to be independent of the incident energy, but was found to be a function of the surface tension. The time of mound formation measurements in clean water at low‐energy acoustic excitations were found to be within 20% of the simulation results. These results imply that surface rise time measurements may present a novel way of measuring surface tension of water–surfactant combinations accurately and rapidly by a simple noncontacting technique.

27 citations


Journal ArticleDOI
TL;DR: In this paper, the nonlinear dynamics of mode interactions in a cyclotron system are studied using a multifrequency, time-dependent model, and the results of numerical simulations for a second harmonic gyrotron are presented by considering two starting scenarios: (a) fast voltage rise or an instant turn-on case, and (b) slow voltage rise case.
Abstract: One of the main obstacles in achieving stable, efficient operation at the cyclotron harmonics in a gyrotron is mode competition with parasitic modes at the fundamental frequency. In this article, the nonlinear dynamics of mode interactions in such a system are studied using a multifrequency, time‐dependent model. The results of numerical simulations for a second harmonic gyrotron are presented by considering two starting scenarios: (a) fast voltage rise or an instant turn‐on case, and (b) slow voltage rise case. For the first case, it is demonstrated that for a certain range of operating parameters, the presence of a parasitic mode at the fundamental can be helpful in the excitation of the second harmonic operating mode. In the second case, it is found that the unstable operating region increases with the value of the rise time constant of the electrode voltages. Stable, efficient gyrotron operation at the second harmonic is demonstrated using the numerical study.

22 citations


Journal ArticleDOI
TL;DR: In this paper, a pre-ionization source for a XeCl laser system is described and a technique to determine the electron density produced by the preionizer is also described.
Abstract: X-ray pulses with rise times shorter than 10 ns and high peak power have been generated using a corona plasma cathode as a fast low-inductance switch. The X-ray generator has been developed as a pre-ionization source for a XeCl laser system and can be used at a repetition rate of a few hundred hertz. A technique to determine the electron density produced by the pre-ionizer is also described.

21 citations


Journal ArticleDOI
TL;DR: Stress pulses with rise times of 1.14 ns and amplitudes in excess of 3 GPa were produced using an Nd:YAG laser in this article, where the tensile strength of planar interfaces between thin coatings of 0.1μm thickness and substrates was also discussed.
Abstract: Stress pulses with rise times of 1.14 ns and amplitudes in excess of 3 GPa are produced using an Nd:YAG laser. In contrast to pulse profile assuming an asymptotic tail at about 5% to 10% of the peak stress, the pulses reported here show much sharper, post‐peak decays resulting in a zero stress at about 17 ns. Use of such stress pulses in the determination of the tensile strength of planar interfaces between thin coatings of 0.1‐μm thickness and substrates is also discussed.

19 citations


Journal Article
TL;DR: In this article, a pre-ionization source for a XeCl laser system is described and a technique to determine the electron density produced by the preionizer is also described.
Abstract: X-ray pulses with rise times shorter than 10 ns and high peak power have been generated using a corona plasma cathode as a fast low-inductance switch. The X-ray generator has been developed as a pre-ionization source for a XeCl laser system and can be used at a repetition rate of a few hundred hertz. A technique to determine the electron density produced by the pre-ionizer is also described.

17 citations


Journal ArticleDOI
TL;DR: In this paper, a passive circuit built with either high-quality coaxial cable of microstrip delay lines can convert a step signal with 25 ps rise time, from a conventional time-domain reflectometer, into a rectangular pulse of duration in the 50 ps-500 ns range, a separate delay line circuit being required for each pulse duration, providing an excellent probing signal for single rectangular pulse testing of analog pulse-shaping circuitry built to operate in the 2 Mb/s to 20 Gb/s range.
Abstract: A passive circuit built with either high-quality coaxial cable of microstrip delay lines can convert a step signal with 25 ps rise time, from a conventional time-domain reflectometer, into a rectangular pulse of duration in the 50 ps-500 ns range, a separate delay line circuit being required for each pulse duration, The system provides an excellent probing signal for single rectangular pulse testing of analog pulse-shaping circuitry built to operate in the 2 Mb/s to 20 Gb/s range. >

15 citations


Patent
05 Mar 1993
TL;DR: In this article, a load driver includes an edge detecting monostable circuit and a plurality of sets of field effect transistor (FET) output devices, one set of the FET output devices having a low drain-to-source resistance and another set having a high drain to source resistance.
Abstract: A capacitive load driver is protected from short circuits to supply or to ground. The load driver includes an edge detecting monostable circuit and a plurality of sets of field effect transistor (FET) output devices, one set of the FET output devices having a low drain-to-source resistance and another set having a high drain-to-source resistance. The low resistance FET output devices provide a desired rise time voltage requirement on a capacitive load being driven. The high resistance FET output devices limit power dissipated under a short circuit to a predetermined amount.

Journal ArticleDOI
P.A. Kok1, D. De Zutter1
TL;DR: In this paper, two different time-domain reflectometry (TDR)-based methods for estimating the equivalent circuit parameters of a via hole are presented, the first method is semigraphical, the second is a numerical estimation technique.
Abstract: Two different time-domain reflectometry (TDR)-based methods for estimating the equivalent circuit parameters of a via hole are presented. The first method is semigraphical, the second is a numerical estimation technique. Estimation is not restricted to equivalent circuit parameters, but onboard unknown rise times and delays are also included. Two possible models for a via hole are compared: a single capacitor model and a pi -network, with two capacitances and an inductance. For certain categories of via hole, the inductive component turns out to be rather important. >

Journal ArticleDOI
TL;DR: In this paper, the laser light intensity is ramped up slowly and linearly (slowly compared to the thermal relaxation time of the system, which is typically 200 ms), and different spatial and temporal patterns are observed.
Abstract: Optical bistability in ferroelectric ceramic lead magnesium niobate at room temperature was discovered recently (Chen et al., Applied Physics Letters, 60, 332, 1992) and characterized in detail as a function of laser power, sample temperature, pressure and flow rate of the ambient air (Scott and Chen, Integrated Ferroelectrics, 1, March 1992). In all these experiments the laser light was incident on the PMN sample with a very fast rise time; thus the switched thermal response of the system was isothermal, with relatively rapid relaxation to steady-state temperatures that are functions of input power. By comparison, in the present study the laser light intensity is ramped up slowly and linearly (slowly compared to the thermal relaxation time of the system, which is typically 200 ms). Under these circumstances the thermal focussing responds adiabatically, and different spatial and temporal patterns are observed. Notable is the hysteretic behavior associated with each switching event; the onset of s...

Patent
29 Mar 1993
TL;DR: In this article, a voltage detecting circuit detects a rise voltage of a generator and compares it with the reference voltage to set a power transistor to the ON state, which can be used to shorten the rise time of the generator voltage.
Abstract: PURPOSE:To shorten a rise time of a generator voltage by detecting rise of a generator to set a power transistor to the ON state. CONSTITUTION:A power supply circuit 10 generates a reference voltage. A voltage detecting circuit 11 detects a rise voltage of a generator 1 and compares it with the reference voltage. An output transitor Q4 is controlled by a voltage detecting circuit 11 and also controls conduction of the power transistor Q1. With detection of the rise time of the generator 1, the transistor Q1 is set to the ON state. Namely, when the generator l enters the operating condition, the power transistor Q1 is immediately set to the ON state, upon detection of a value or frequency of the voltage generated at the initial stage of the operation and the voltage generated is impressed in direct to an excitation coil 3 in order to permit a suffucient excitation current to be fed. Thereby, a rise time of the generator 1 can be shortened.

Journal ArticleDOI
TL;DR: In this paper, the self-pumped phase conjugation is from internally seeded stimulated photorefractive backscattering and the four-wave-mixing rise time of the 45-deg-cut crystal is 4 ms with a reflectivity of 48 percent.
Abstract: Relatively fast self-pumped phase-conjugate and four-wave-mixing rise times are reported in n-type cobalt-doped barium titanate. With the crystal oriented in a 45-deg cut as compared with the same crystal in a 0-deg cut we find a factor of 3 decrease in the 0-90-percent rise time to 800 ms with 25-mW input power at 514.5 nm. Also, the self-pumped phase-conjugate reflectivity increases from 20 to 40 percent. We deduce that the phase conjugation is from internally seeded stimulated photorefractive backscattering. The four-wave-mixing rise time of the 45-deg-cut crystal is 4 ms with a reflectivity of 48 percent when the pumping beams are derived from self-pumped phase conjugation that has an input power of 25 mW.

Journal ArticleDOI
TL;DR: In this paper, a simple and relatively inexpensive circuit that produces a faster warning signal using a conventional lamp was designed to reduce reaction times to the onset of brake lamps by about 115 ms.
Abstract: Conventional tungsten–filament brake lamps have a relatively slow rise time. It takes approximately 250 ms for them to reach 90% of their asymptotic luminous intensity. This slowness of response can cause important delays of warning information to following drivers. We have designed a simple and relatively inexpensive circuit that produces a faster warning signal using a conventional lamp. As we have reported previously, this device reduces reaction times to the onset of brake lamps by about 115 ms. The present study evaluated the benefits of a 115 ms reduction in driver brake reaction time. Two approaches were used. In the first approach we calculated the reductions in effective stopping distance assuming a range of initial speeds. The results indicate, for example, that if the initial speed is 100 km/h. the reduction in the effective stopping distance is 3–2 m. In the second approach we calculated the reductions in the proportions of very long reaction times, assuming a normal distribution of reaction t...

Journal ArticleDOI
TL;DR: The design, fabrication, and results of an optoelectronic device that computes the weight changes required by the delta-rule learning algorithm and encodes the result on a pair of optical beams are presented.
Abstract: The design, fabrication, and results of an optoelectronic device that computes the weight changes required by the delta-rule learning algorithm and encodes the result on a pair of optical beams are presented. This very-large-scale-integrated ferroelectric liquid-crystal array was designed specifically to permit bipolar optoelectronic neural networks to learn without the limitations of an external controlling computer. The device contains 64 smart pixels, which represent the processing elements in an artificial neural network. Each processing element consists of two photodetectors, a current-to-voltage converter, two comparators, two switches, and two output liquid-crystal modulating pads. The device has a measured contrast ratio of 10:1, a 10%-to-90% rise time of 350 μs, and a 90%-to-10% fall time of 150 μs.

Patent
03 May 1993
TL;DR: In this paper, a circuit is provided that reduces the electromagnetic emissions from an integrated circuit, which includes the resistive portion of an intrinsic low pass filter network and a means for modulating the resistance in response to switching of the integrated circuit nucleus logic elements.
Abstract: A circuit is provided that reduces the electromagnetic emissions from an integrated circuit. The circuit includes the resistive portion of an intrinsic low pass filter network and a means for modulating the resistance in response to switching of the integrated circuit nucleus logic elements. The resistance is increased before the nucleus logic elements switch and is gradually decreased upon completion of all switching of the nucleus logic elements. A portion of the transient switching pulse waveform, normally provided by the external power supply, is instead provided by the intrinsic nucleus capacitance associated with the nucleus logic. In particular the high frequency components are sourced by the intrinsic nucleus capacitance. The amplitude and the rise time of the transient switching pulse is thereby reduced. Further reduction in electromagnetic emission is provided by modified output buffers where transient switching waveforms are reduced by current limiting the output switching transistors and providing initial transient current from the intrinsic capacitance associated with the output buffer.

Journal ArticleDOI
TL;DR: In this paper, a time-resolved Q-band (35GHz) electron paramagnetic resonance (EPR) apparatus with a 25ns rise time and 10ns time resolution is described.
Abstract: A time‐resolved Q‐band (35‐GHz) electron paramagnetic resonance (EPR) apparatus with a 25‐ns rise time and 10‐ns time resolution is described. Built around the Varian E110 microwave bridge, a detailed description of the resonator, flow system, optical alignment, and preamplifier electronics is given. The resonator is a TE103 rectangular cavity with front and back cutoff flanges attached to allow maximum laser light access. An adjustable Gordon coupler was constructed to achieve critical coupling to the cavity. Two separate designs of quartz sample flow cell are described, one for low dielectric organic solvents and one for aqueous samples. The standard diode detection system as shipped by Varian was used, but the signal from the detector diode was branched into two separate amplifiers, one the standard preamplifier for automatic frequency control lock‐in operation, the other based on a Comlinear op‐amp which gave fast rise times (9 ns) before the signal was trapped by a boxcar signal averager. Test system...

Patent
23 Aug 1993
TL;DR: In this article, an edge-triggered comparator circuit comprising a first Josephson junction connected between a signal input node and an output node and a sampler network coupled to the output node is described.
Abstract: The invention includes an edge-triggered comparator circuit comprising a first Josephson junction connected between a signal input node and an output node and a sampler network coupled to the output node. The first Josephson junction is part of a low inductance SQUID which exhibits a periodic transfer function whose periodicity is a function of the current injected into the SQUID. The sampler network includes a second Josephson junction connected between a sampling terminal and the output node and a third Josephson junction connected between the output node and a point of reference potential. "N" comparator circuits embodying the invention may be interconnected to form an "N"-bit flash analog-to-digital (A/D) converter. The A/D converter may include an R-2R resistive ladder network connected between an analog signal input terminal and a point of reference potential. The resistive ladder network has N nodes with a different comparator being connected to each node. The signal current flowing along the resistive network is divided down by the ladder network such that the current flowing into each succeeding comparator is one-half the current flowing into the preceding comparator. In A/D circuits embodying the invention, there is included an "on chip" step generator circuit responsive to an external sampling signal for producing a sampling step signal having a very short rise time. The sampling step signal is applied to the sampling terminal of all the comparators via circuitry designed to ensure that all the comparators are driven with essentially the same type of step signal.

Journal ArticleDOI
TL;DR: In this article, the authors determined the rise time and magnitude of the source force from the time domain signals without a deconvolution procedure, under the assumption of the force as a ramp force.
Abstract: Glass capillaries of various sizes were broken on a steel plate and the source force was determined from the epicentral displacement. The rise time and magnitude of the source force were directly determined from the time domain signals without a deconvolution procedure, under the assumption of the source force as a ramp force. The rise time of signals at the arrival time of longitudinal waves corresponded to the rise time of the source force, and the signal level at the arrival time of transverse waves was proportional to the magnitude of the ramp force. The magnitude of the source function showed a different linearity depending on the ID/OD, the larger the force the larger the cross-section area. The rise time of glass capillary breaks is equivalent to the time required for capillary fracture, the longer the rise time the thicker the capillary in mean diameter. The average crack velocity in the glass capillary determined from the relationship between the rise time and the capillary diameters was 0.284cl, where cl is the longitudinal wave velocity.

Journal ArticleDOI
TL;DR: In this article, a high-performance, low-noise charge preamplifier integrated circuit is designed and tested for the Superconducting Super Collider, and the amplifier is fabricated in a new dielectrically isolated (DI), radiation-hardened, very high-frequency (VHF) BIFET IC process technology from Harris Corporation.
Abstract: A high-performance, low-noise charge preamplifier integrated circuit is designed and tested for the Superconducting Super Collider. The amplifier is fabricated in a new dielectrically isolated (DI), radiation-hardened, very-high-frequency (VHF) BIFET IC process technology from Harris Corporation. This new process provides n-p-n, p-n-p, and p-channel JFET devices which are both radiation-hardened, tested to 3 Mrad of total gamma ray exposure and 3*10/sup 14//cm/sup 2/ neutron dosage, and provides high-frequency performance. The new charge preamplifier provides improved performance with an output rise time of 65 ns, input inferred noise of 28.6 mu V, or 3575 electrons, and power dissipation less than 33.7 mW. The circuit design is discussed with attention given to those design characteristics needed to specifically accommodate low noise with the new radiation-hardened process. >

Patent
17 Sep 1993
TL;DR: In this paper, two controlled current gate drives are provided for driving parallel P and N channel pass devices, so that the rise time of the voltage at one gate of the pass devices overlaps with the fall time of another to reduce capacitive signal coupling of the signal applied to an FET gate to the FET source and drain.
Abstract: Two controlled current gate drives are provided for driving parallel P and N channel pass devices, so that the rise time of the voltage at one gate of the pass devices overlaps with the fall time of the other to reduce capacitive signal coupling of the signal applied to an FET gate to the FET source and drain. Low-level current sources drive the gates of the pass devices with opposite polarities. A current mirror is used to control the currents provided by the gate drives to control the tradeoff between switching speed and switching noise coupling.

Journal ArticleDOI
TL;DR: In this paper, the transient forward bias current as a function of repetition rate and reverse bias between forward bias pulses in a-Si:H p-i-n devices which have thin or thick i-layers was presented.
Abstract: We present the transient forward bias current as a function of repetition rate and reverse bias between forward bias pulses in a-Si:H p-i-n devices which have thin or thick i-layers. Little repetition rate and reverse bias effects were found in thin (0.4μm) samples compared with thick ones (> 2.0 μ m), implying that the junctions recover faster than the bulk when subjected to excess carriers due to the bias. For thick samples to reach steady state requires the pulse repetition rate to be lower than 10 −4 Hz. Further, reverse bias increases the initial space charge limited current, delays the transient rise from space-charge-limited- to recombination-limited-current but has no effect upon the final forward bias current. More pronounced delay of the rise time was found in devices which have been light-soaked. We suggest that notonly the deep traps but also defect relaxation may be responsible for these slow decay and slow recovery effects.

Proceedings ArticleDOI
31 Oct 1993
TL;DR: In this article, two types of photodiodes have been experimentally investigated to be applied in electron tubes to achieve fast response characteristics such as 2.7ns in rise time and more than an order of increase of dark current.
Abstract: As a fiindamental study of photodiodes (PDs) for electron bombardment, two types of PDs have been experimentally investigated to be applied in electron tubes. A PD bombarded from the fiont surface (FB-PD), where pn junction of planer structure existed, was evaluated to perform fast response characteristics such as 2. Ins in rise time, however, more than an order of increase of dark current was also confirmed after a long term stability test of 1000 hours. On the other hand. a PD bombarded by electrons from the rear surface (RB-PD) was measured to show no increase of dark current after the stability test and fast rise time of 2.7ns. However, it was clarified that the rise time of RB-PD depended on applied voltage to the PD, and applied voltage of 200V was necessary to achieve such fast response. Since it was much higher voltage than it was expected, some modifications may be necessary to achieve fast response with lower applied voltage, considering a yield of the PDs. Comparison of two types of PDs on some other characteristics are discussed. Preliminary test result of electron bombardment APD is also discussed.

Journal ArticleDOI
TL;DR: In this paper, the authors measured the response of natural type IIa diamonds to single-particle excitations and found that the shape of the pulse tails changes from approximately exponential to approximately gaussian in form.

Journal ArticleDOI
TL;DR: In this article, a theoretical analysis for calculating the transient device junction temperature as a function of position and time upon a stepwise increase of power dissipation is presented, which applies in particular to multifinger heterojunction bipolar transistors designed for microwave power application.
Abstract: We present a theoretical analysis for calculating the transient device junction temperature as a function of position and time upon a stepwise increase of power dissipation. The derivation applies in particular to multifinger heterojunction bipolar transistors designed for microwave power application. It is determined that for a typical substrate thickness of 100 µm, the rise time of the junction temperature is roughly 3×10-7 s.

Journal ArticleDOI
TL;DR: In this article, a pulse shape discrimination technique has been applied to improve the energy resolution of a single wire anode (SWA) gas scintillation proportional counter (GSPC).
Abstract: Pulse shape discrimination technique has been applied to improve the energy resolution of a single wire anode (SWA) gas scintillation proportional counter (GSPC). Resolution at 5.9 keV photon energy is improved from 33% to 16% by suppressing pulses due to interactions in the scintillation production region (SPR) in a 1.7 mm diameter rod anode cylindrical design GSPC operated with Ar + 2.5% N 2 in continuous flow. For the optimum operating conditions of the GSPC the rise time of the pulses due to 5.9 keV X-rays was typically 300 ns for interactions outside the SPR and a broad continuum from 300 ns down to about 40 ns for interactions inside the SPR. In order to select a certain narrow time window a special time to amplitude converter unit was developed with a time resolution capability to distinguish pulses having rise times differing only by a few ns.

Proceedings ArticleDOI
M.J. Barnes1, G.D. Wait1
17 May 1993
TL;DR: In this paper, the authors used PE2D to determine inductance and capacitance values for the resistive terminator of a TRIUMF 10-cell prototype kicker magnet.
Abstract: Kicker magnets are required for all ring-to-ring transfers in the 5 rings of the proposed KAON factory synchrotron. The kick must rise from 1% to 99% of full strength during the time interval of gaps created in the beam (80 ns to 160 ns) so that the beam can be extracted with minimum losses. In order to achieve the specified rise-time and 'flatness' for the kick it is necessary to utilize speed-up networks, comprising a capacitor and a resistor, in the electrical circuit. Speed-up networks may be connected electrically on both the input and output of the kicker magnet. In addition it is advantageous to connect a 'speed-up' network on the input of the resistive terminator(s). A sequence which may minimize the number of mathematical simulations required to optimize the values of the 8 possible speed-up components is presented. PE2D has been utilized to determine inductance and capacitance values for the resistive terminator; this data has been used in PSpice transient analyses. Results of the PE2D predictions are also presented. The research has culminated in a predicted kick rise time (1% to 99%) of less than 50 ns for a TRIUMF 10 cell prototype kicker magnet. The proposed improvements are currently being implemented on our prototype kicker system. >

Proceedings ArticleDOI
15 Nov 1993
TL;DR: In this article, a digital controller based on the waveform detection technique which uses the inactive phase chop current rise time is implemented to drive a 3-phase variable reluctance (VR) step motor.
Abstract: The waveform detection technique detects rotor position in variable reluctance (VR) motors indirectly by monitoring rise or fall times of the chopped phase current waveform. The chop rise and fall times can be either of an active or inactive phase. In this paper an investigation is made for using chop phase current rise time of an inactive phase for rotor position detection. A digital controller based on the waveform detection technique which uses the inactive phase chop current rise time is implemented. The analysis together with experimental results obtained by applying the controller to drive a 3-phase VR step motor suggest that: the use of chop current rise-time leads to instability in the drive system and hence is not recommended. On the other hand, chop fall-time provides stable operation and therefore, is recommended. An algorithm implemented to start and run the VR step motor from standstill position maintaining correct direction of rotation is also presented. >