R.J. Stubbs

Multiwire corona chambers with small wire spacing

Abstract Several small multiwire corona chambers have been built in order to test the usefulness of such multiwire systems. The chambers had small sense wire spacings varying from 2 to 4 mm. The general characteristics of the chambers have been studied using argon as the gas filling. It has been shown that a chamber with 4 mm spaced sense wires of 20 μm diameter operates satisfactorily with a signal-to-noise ratio of 2:1.

GENERAL PROPERTIES OF THE CURRENT-LIMITED SPARK CHAMBER.

Abstract The operating characteristics of sealed, current limited spark chambers filled with 98% neon, 2% helium have been studied and are found to be similar to those of the more conventional chambers in many respects. However, some properties of the chambers show anomalous effects which are suggested as being due to an internal electric field caused by the discharges.

Some results on the sensitivity of the RCA 4522 photomultiplier tube

Abstract Measurements have been made of the spatial and relative spectral sensitivities of the photocathode → dynode (1) structure of the RCA 4522 photomultiplier tube. These exhibit significant variations and non-uniformity, as expected.

A seven channel gated charge to time converter

Abstract By using a hybrid integrated circuit seven independent gated charge to time converters have been constructed in a single width NIM module. Gate widths from ⪅10 ns to ∼300 ns are possible with a resolution of 0.25 pC, linearity is better than ±1 pC over 2.5 decades of input signal height. Together with a multichannel scaling system described in the following paper one has a very powerful multichannel gated ADC system.

Localisation of the discharge in the multiware corona counter and the possibility of building a counter with two-dimensional read-out

Abstract The localisation of a corona discharge has been shown and a two-dimensional image of an α-particle source in a multiware corona chamber has been obtained.

A simple time stretcher with high resolution

Abstract A simple time stretcher has been built having a linearity over the range 500 ns to 10 μ s of ±0.6%, a resolution of ≲ 2 ns and a temperature coefficient of ⩽ 0.05%/°C. Time magnifications ≲ 10 were used.

Spark chamber efficiency in the presence of very small clearing fields

Abstract A method of calculating spark chamber efficiencies in the presence of very small clearing fields, of the order of 1 V/cm, is given and some applications to sealed glass spark chambers are discussed.

Edge profiles of spark chamber frames

Abstract The problem of edge breakdown in spark chambers is considered and is shown to be due to field distortion at the gas dielectric interface. Consideration is given to several edge profiles, made from commonly used materials, which are expected to minimize the field distortion. Results show good agreement with the qualitative theory.

Some properties of a gridded drift chamber for X-ray detection

Abstract A solid converter consisting of alternate sheets of brass and insulating material has been placed above a multi-wire proportional chamber 1 ). X-rays were converted to photo electrons in this dense material and the electrons drifted through holes in the sheets into the chamber where they were detected. It was found that a drift field inside the converter of only a few hundred volts per cm was required to drift the electrons into the chamber. The spectra of pulse heights from the chamber have been measured.

An eight channel fast scaler

Abstract An eight channel 64-bit scaler has been constructed with a static CMOS memory. Scaling frequencies are independently variable, at each channel, as are the number of bits/channel. The scaler, when used in conjunction with a multichannel charge to time converter (see previous paper) results in a very flexible, gated multichannel ADC.