Standard Photomultiplier Research Articles

A high-speed photomultiplier gating circuit for luminescence measurements

A high-speed, normally on, gating circuit has been developed for linear-focused photomultipliers such as the EMI 9816. The gate is capable of attenuating photomultiplier response by >5000:1 with a turn-off and turn-on time of 60 and 40 ns, respectively. The circuit is compact enough to fit in a standard photomultiplier housing and has low enough power consumption to run off the photomultiplier high-voltage supply. The high speed and high extinction efficiency make this gate suitable for pulse rejection in low-light level, submicrosecond, time-resolved luminescence measurements.

Results on the Performance of a Broad Band Focussing Cherenkov Counter

The field of ring imaging (broad band differential) Cherenkov detectors has become a very active area of interest in detector development at several high energy physics laboratories. Our group has previously reported on a method of Cherenkov ring imaging for a counter with large momentum and angular acceptance using standard photo multipliers. Recently, we have applied this technique to the design of a set of Cherenkov counters for use in a particle search experiment at Fermi National Accelerator Laboratory (FNAL). This new detector operates over the range 0.998 < ß < 1.000 in velocity with a δß ~ 2 x 10-4. The acceptance in angle is ± 14 mrad in the horizontal and ± 28 mrad in the vertical. We report here on the performance of this counter.

Ultraviolet Cherenkov light detector

An increase by a factor ∼3.4 in photoelectron emission from Cherenkov light has been observed after coating a standard photomultiplier of the XP1040 class (Philips) with a thin deposit of scintillating material (wavelength shifter). The coating operation is straightforward and requires simple manipulations. We have used coated phototubes in a conventional gas Cherenkov counter exposed to an electron beam at the CERN PS. We measure a figure of merit for the system of N 0∼ 170 photoelectrons per cm.

Use of Channel Electron Multipliers as Secondary Standard Detectors at EUV Wavelengths

The procedures available for photometric calibration at extreme ultraviolet (EUV) wavelengths are outlined and the requirements for a secondary standard EUV photomultiplier defined. The performance of a number of commercially available channel electron multipliers over the 304-1350-A wavelength range is described and their suitability for use as secondary standards discussed in detail. Although none of the multipliers evaluated fully met the requirements for a secondary standard it proved possible to calibrate absolutely a Mullard cone channel over the required wavelength range to an accuracy of +/-9% and to employ it as a secondary standard in the calibration of a series of sounding rocket spectrometers.

A Measuring System for Studying the Time-Resolution Capabilities of Fast Photomultipliers

A measuring system has been developed for studying and optimizing the time-resolution capabilities of fast photoelectric devices, such as standard and microchannel type photomultipliers. The system incorporates a subnanosecond light-pulse generator capable of operating at repetition frequencies up to 3 MHz with output light pulses having a full width at half-maximum of less than 200 psec, and a zero-crossing discriminator which has a time walk of ±40 psec over a 170 mV to 8 V input-pulse amplitude variation. Averaging the data from several successive measurements, the measuring system time resolution is 20 psec.

Scintillation guard detectors for low-activity beta measurements with Geiger-M$uuml$ller counters

The design of compact plastic-scintillator guard detectors for low background beta measurement is described. Their performance is compared with other available guard detectors and background count-rate reductions are demonstrated. The demountable assemblies for 1 and 2 in window Geiger-Müller counters can be readily manufactured and are arranged to fit standard AERE photomultiplier housings. Typical backgrounds in 4 in lead shields are 0·5 counts per minute for the GM4LB and 4·9 counts per minute for the 2B2.

New Detector for the Vacuum Ultraviolet

A new method is described for detecting vacuum uv radiation. This radiation is converted to visible light in two steps, the first being creation of photoelectrons at a high voltage cathode, the second consisting of stopping these electrons in a scintillator at ground potential. The visible scintillations are detected with a standard photomultiplier. The system has been compared with a sodium salicylate detector, using a vacuum uv monochromator and a steady light source. Spectral lines between 500 and 1300 Å have readily been recorded. Compared to other systems, the new detector offers a number of advantages which are discussed. Preliminary results for pulsed light sources indicate that the method is also useful for studying phenomena whose time scales are of the order of 1 μsec.