Coincidence Scheme Research Articles

A high speed magnetic printer

A nonimpact magnetic printer is described that features quiet high-speed operation, uses plain paper and single component dry toner, and produces good copy at high humidity. The printer operates at 6000 lines/minute at a density of six lines per inch (lpi). A stationary printing head, 14-in long, records rows of dots at 120 dots per inch (dpi) on a flexible magnetic belt. The recorded dots are selected by a coded digital input to form alphanumeric characters. The system can also function as a plotter. The 1680 printing locations on the magnetic recording head are selected by a coincident current scheme that utilizes novel integrated drive circuitry. The magnetic image is developed with a single component dry magnetic toner and the toner image is transferred to paper and thermally fused thereto.

An on-line method for tritium breeding studies in Li-blankets

An on-line method for tritium breeding measurements in lithium blankets is described. The apparatus comprizes two tiny ionization chambers (≈ 1.3 cm 3 each) separated by a common electrode holding 6LiF radiating materials. Tritium producing events due to neutron interaction with the radiating material result in triton and alpha particles flying approximately in opposite directions which can be detected by the respective ionization chambers. A coincidence scheme is incorporated to sort out real events from single events. The spatial tritium production measured with the help of the double ionization chamber in the case of a LiAlO 2 blanket having lead as a neutron multiplier and polyethylene as a moderator is compared with that of MORSE calculations.

A microcomputer based multiple detector data acquisition system

A multiple detector system for performing up to twenty-five simultaneous coincidence measurements is described. A microcomputer is used to store data, control the experiment and perform elementary analysis. Data rates for the system are up to a factor of twenty-five greater than in conventional two detector coincidence schemes, and systematic errors due to changes in the experimental variables are minimized.

A Contribution to the Multiple-Polarity Coincidence Detection Schemes

A new approach to multiple-polarity coincidence schemes has led to a relatively simple detector that is superior when compared to other diversity detectors. The new detector is also nonparametric and operates well in general noise environments.

Versatile Gated Discriminator with Adjustable Paralysis Useful in Fast-Slow Coincidence Experiments

The discriminator described incorporates a number of features useful in nuclear applications. The paralysis, or deadtime, is adjustable from 100 nsec to 10 msec; at a fixed temperature it is stable to within ±1%, even for pulse pair separations approaching the paralysis time: hence deadtime corrections are correspondingly accurate. Two pairs of 100 MHz logic outputs and a separate scaler driver output are provided. The scaler output can be controlled by external coincidence gating or blocking signals. These gating provisions make it possible to connect a dual module (without additional circuitry) as a single channel analyzer, as an antiwalk discriminator for precise coincidence timing, or even as a coincidence circuit. The primary application is, however, coincidence counting when one or more side channels are needed for amplitude selection. The coincidence gating provision of this discriminator permits one to dispense with lengthy external delay compensation required by conventional energy selecting coincidence schemes. The similarity of the three approaches—conventional slow-fast, conventional fast-slow, and gated fast-slow—in terms of coincidence computations and accidental monitoring is demonstrated, and criteria are presented to aid in selection of one technique over the others.

POLARITY COINCIDENCE SCHEME FOR REVEALING SIGNAL COHERENCE

A simple statistical procedure, based on multiple coincidence of field polarities as indicated by several receptors, offers a criterion of the existence of a signal below the general noise level. As an example, with six receptors in a field where there is a sine wave signal ten decibels below the noise level, there will be twice the number of coincidences that would be obtained for the noise alone. A scheme is shown to illustrate how an electrical system can perform the analysis and present the results continuously.

Slow-Neutron Capture Gamma Rays from Sodium and Cadmium

A thin-lens magnetic spectrometer has been used to observe the external conversion spectra of ${\mathrm{Na}}^{23}(n, \ensuremath{\gamma}){\mathrm{Na}}^{24}$ and ${\mathrm{Cd}}^{113}(n, \ensuremath{\gamma}){\mathrm{Cd}}^{114}$ and the internal conversion spectrum of ${\mathrm{Cd}}^{113}(n, \ensuremath{\gamma}){\mathrm{Cd}}^{114}$ in the energy range of 300 kev to 3 Mev. An arrangement using an external neutron beam and one using a source located inside the reactor are compared. It is shown that target materials placed inside the reactor allow a better discrimination against background and permit the use of a $K$ x-ray-conversion-electron coincidence scheme for photoelectric conversion which greatly simplifies the observed conversion spectrum. Four of the nine gamma rays observed from sodium are assigned to transitions on the basis of the known energy levels from ${\mathrm{Na}}^{23}(d, p){\mathrm{Na}}^{24}$; the other five are assigned to probable transitions on an energy and intensity basis. The internal conversion spectrum of ${\mathrm{Cd}}^{114}$ has disclosed a 0+ level at 1308\ifmmode\pm\else\textpm\fi{}3 kev and the de-excitation of this level by means of $E2$ transitions to other states in ${\mathrm{Cd}}^{114}$ is also observed. Three other states in ${\mathrm{Cd}}^{114}$ are proposed in addition to the well-known 559-kev (2+) and 1286-kev (4+) states to explain the observed gamma-ray spectrum: 1212\ifmmode\pm\else\textpm\fi{}3 kev (2+ or 1+), 1368\ifmmode\pm\else\textpm\fi{}4 kev (2+ or 1+), and 1860+5 kev (4+ or 3+).

Proposed Coincidence Scheme for the Elimination of the Doppler Effect

Proposed Coincidence Scheme for the Elimination of the Doppler Effect