Pulse Stretcher Research Articles

Design of a block replicate gate for ion-implanted bubble devices

A block replicate gate has been designed for 4 μm period ion-implanted bubble devices. The gate consists of a conductor lying across a V-shaped unimplanted pattern between the minor loop end and the major line. Replication is accomplished by stretching the bubble with a stretch pulse through the conductor, cutting the domain by means of the charged wall formed at the edge of the V-shaped pattern together with a pulse of short duration, then restoring the bubble to the original condition by means of another stretch pulse. A bias field margin of 20 Oe was obtained with an error rate of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-5</sup> for a 100 kHz, 80 Oe peak triangular drive field.

A Proposal for a High Current, High Duty Factor Electron Accelerator

A linac-Pulse-Stretcher-Ring has been proposed for the generation of high duty factor, high current electron beams in a nominal energy range of 0.5 to 2.0 GeV. A low duty factor linac beam is injected into a storage ring from which it is slowly extracted to yield a high duty factor. The linac beam is composed of 1.2 ?s current pulses containing 240 nC/pulse with a repetition rate of 1 kHz. Each pulse is injected vertically during a single turn into the pulse stretcher ring, a 377.89 m oval with a magnetic radius of 29 m. Excitation of an n/3 betatron resonance in the horizontal plane is used in conjunction with electric and magnetic septa for extraction. Typical extracted beam parameters are: horizontal emittance ?0.37? mm-mrad, vertical emittance ?0.l? mm-mrad, and an energy spread ?0.1%. The extracted beam has a maximum average current of 240 ?A, a duty factor >90%, and may be polarized. Beam characteristics, design parameters, and facility layout are discussed.

ALFA, Feasibility Study of an Electron Pulse Stretcher to Increase the Duty Factor of the Frascati Linac

The present duty-factor of the 400 MeV Frascati National Laboratories Linac (8x10-4) can be made to approach unity by using an electron storage ring as a pulse stretcher: resonant extraction near an m/3 resonance by means of sextupolar nonlinearities in the ring allows slow extraction of the stored current with small energy spread. The feasibility of a machi ne, capable of 100μA average current and 10-3 energy spread between 200 and 500 MeV is investigated. The optical structu re of a ring, 120 m long with a 5 m bending radius, is presen ted. The necessary modifications to the Linac are indicated. Expected parameters of the extracted beam are presented.

On Improved Digital Techniques of Pulse Width Measurement

A digital technique for the instantaneous measurement of pulse width is described in this paper. The techniques make use of a 50 per cent amplitude sampling circuit which converts the varying amplitude pulses into the fixed amplitude pulses require to work with the pulse stretcher and a special stretcher circuit which generates a pulse 100 times as wide as the input pulse. The 50 per cent amplitude sampling circuit senses the peak amplitude and establishes a half amplitude reference level to measure the pulse width of its 50 per cent amplitude. The stretched pulse is used to control the outputs of an oscillator and counter, thereby providing a digital output. The gas discharge numerical indicator tubes allow the pulse width to be read directly in digital form. Accuracy of ± 2 per cent has been achieved for range 0·35–1·2 μsec. pulses with a resolution of 0·01 μsec. A special input circuit is provided which selects only the first two pulses, and uses the second input pulse for measurements.

Inductance meter based on a tunnel-diode pulse stretcher

Inductance meter based on a tunnel-diode pulse stretcher

A novel linear pulse stretcher†

The design principle of a basic pulse stretcher circuit is discussed and a novel linear pulse stretcher circuit is reported. The salient feature of the pulse stretcher is that the circuit is simple and inexpensive for the linearity achieved.

Concept and General Design of an Electron Pulse Stretcher

This paper presents the project of an electron pulse stretcher (E.P.S.) for the 100-300 MeV electron linear accelerator of the University of Saskatchewan. We briefly outline the results of a previous study made by the particle optics division (S.O.C.) of Saclay for the project ALIS and show its relation to our design. The present E.P.S. machine design and characteristics are discussed and finally some remarks are made on tolerances and vacuum requirements. More detailed information can be obtained in our internal reports.

Injection in a Ring with Non Linear Elements and Energy Selective Resonant Extraction from a Ring

The paper presents the main ideas involved in the injection and extraction procedures for the electron pulse stretcher (E.P.S.) designed for the linear accelerator of the University of Saskatchewan. The E.P.S. is described in another paper presented at the conference (D-5). The interested reader can find more detailed information on injection and extraction in our internal reports.

A time derandomizer for analog pulses

A storage unit for analog pulses is described which is used to decrease counting losses in high-rate, high-resolution, pulse-height analysis experiments. Three pulse stretchers connected in series store up to three pulses until they can be processed by an external analog-to-digital converter. An effective dead time of 6 μs is achieved when analyzing randomly occuring pulses at rates up to 20 000 cps. No degradation in pulse height resolution due to the insertion of this instrument has been detected.

Processing of Detector Signals at Very High Counting Rates for Precision Pulse-Height Analysis

Systems with naxiwum pulse flow capacity are discussed. It is shown that the upper limit of the permissible counting rates is set by pile up induced phenomriena, which are analyzed here. The best pulse stretching mode miinimizing pile up is peak value extraction. The basic statistical properties of such a device are investigated. These principles are applied to the design of an electronic system which comprises a fast amplifier, a high speed linear gate and a biased pulse stretcher. The noise properties of the anmplifier were studied using the autocorrelation function mreasured experimrentally. The system allows one to detect a particles with satisfactory pile up performances and negligible spectrum distortion in the presence of back-scattered protons up to 108 counts/sec. Applications to pulsed high energy accelerators are described.

Amelioration de la linearite differentielle des convertisseurs a poids

The considerable influence of the pulse stretcher on the differential linearity of a weighted converter is shown and discussed. Theoretical histograms are derived from the relationship between the channel-width and the stretcher slope. Finally, we describe a circuit which carries out a new sequence of successive comparisons, entirely eliminating the influence of the stretcher on the differential linearity. Experimental spectra obtained through this method confirm the theoretical predictions.

The use of derandomizers for the prevention of spectrum distortion

Distortion may occur in the case that two or more time-correlated peaks are present in a recorded spectrum. Such distortion may be reduced significantly by using a derandomizing analogue or digital buffer. Several examples of such correlated spectra will be given together with suitable block diagrams. The resulting reduction of spectrum-distortion will be analyzed quantitatively. Finally, a short description will be given of the basic electronic circuit and its possible modification as a pulse stretcher, window amplifier, or combined derandomizer. As a pulse stretcher, the analysis of comparatively fast pulses by a slow ADC is made possible; as a window amplifier, the required bandwidth of the following circuits is significantly reduced by stretching the pulse before applying the bias; in the combined derandomizer and window amplifier, only those pulses reach the ADC whose amplitude exceeds the window bias. Pulses whose amplitude is smaller than the bias do not participate in the derandomizing process.

Analog-to-digital converter nonlinearity due to the loss current

A pulse amplitude error is analyzed in this paper, which occurs in pulse stretchers due to the RC-shaped input pulses when the loss current cannot be neglected. An expression is derived showing the dependence of this error on pulse amplitude, loss current and pulse shape.

Simple linear pulse height averager and recorder adaptor circuit for use with the Tektronix type N sampling oscilloscope

A complete, simple electronic adaptor unit is described which allows the use of an X-Y recorder with the Tektronix type N sampling oscilloscope system. The unit contains a pulse height averager circuit that is essentially a cathode follower pulse stretcher, and that gives a vertical (Y) channel mean output voltage proportional to the mean height of the short output pulses from the sampling oscilloscope, irrespective of their repetition rate. The unit has proved to be of value when recording electrical pulses of shapes fluctuating about a mean, as photomultiplier pulses due to very weak but identical photon pulses.

Non-integrating stretcher for pulses of 6 to 300 ns length

Non-integrating stretcher for pulses of 6 to 300 ns length

A beam pulse stretcher of the synchro-cyclotron

A r.f. beam pulse stretcher has been applied successfully to the Carnegie Institute of Technology 450 MeV synchrocyclotron. The beam pulses are stretched completely. The duty factors are almost unity for the long time scale and less than two for the nanosecond time scale due to the phase bunch. The beam loss is 30–40 percent of the bunched beam.

A PULSER CURCUIT FOR RELAY PROGRAMMING WHICH WILL STRETCH PULSES.

A PULSER CURCUIT FOR RELAY PROGRAMMING WHICH WILL STRETCH PULSES.

Anemometer Pulse Stretching

Pulse stretching, to increase the maximum speed of dependable response of many contacting anemometer-sensor combinations is outlined, with summary theory, extant equipment references, and circuitry of a minimal pulse stretcher. The suitability of various types of equipment for various situations is also outlined.

Stretcher for Short Counter Pulses

First Page

Instrumentation at the ETH

After a brief outline of applications of scintillation counters to nuclear studies at ETH (Eidgenoessische Technische Hochschule), some topics in electronic circuit developments are selected for a more detailed discussion. 1) A linear overload-protected amplifier is described in which pulse shape parameters can be adjusted independently. 2) In the linear amplifier double rectangular pulse shaping is produced by a ferrite core delay line of novel design. Higher order phase corrections are obtained by a combination of inductive and capacitive couplings. 3) Fast timing signals are derived from slow scintillation pulses using a nonlinear amplifier circuit. Amplitude-dependent time jitter is reduced by a special design of interstage couplings. 4) Requirements to be met by pulse stretchers are listed, and a corresponding circuit diagram is presented. 5) Ultrasonic delay lines can be used for the storage of channel counts in a pulse spectrometer. A new type of magnetostrictive transducer has been developed in order to improve the reliability of such a memory. Increased signal amplitude is obtained along with a suppression of unwanted reflections. 6) Straightforward decimal coding, as used in ultrasonic storage and in electrostatic storage type pulse spectrometers, will be explained briefly. Automatic data recording from the CRT display of the ultrasonic memory spectrometer is demonstrated. The electrostatic memory spectrometer is presently operative with four decimals on each of 32 columns in the storage tube. 7) A possible way of using a pulse spectrometer for automatic computing in the analysis of complex scintillation spectra is suggested.