BS IEC 60462:2010 pdf free download

BS IEC 60462:2010 pdf free download

BS IEC 60462:2010 pdf free download Nuclear instrumentation — Photomultiplier tubes for scintillation counting — Test procedures
4Test conditions
Test conditions for photomultipliers are specified in terms of environmental conditions thatshall be met to enable accurate measurements of the photomultiplier parameters discussed inthis standard.
Power supplies should be stabilized and,in particular,high-voltage power supplies shouldhave regulations of 0,01 % or better, and ripple and noise should be not more than 10 mvpp·The test enclosure shall be free of detectable light leaks.This can be verified by half-hourphoton counting periods,with and without bright ambient light incident on the enclosure.
The PMT should be stored in darkness for 1 h prior to measurement to avoidphosphorescence effects.Cleanliness of the PMT glass and sockets is essential in preventingexternal noise effects. Any material near the photocathode should be at photocathodepotential to prevent electro-luminescence of the envelope and electrolysis or chargeaccumulation of the glass. To obtain the best conditions for reproducibility of tests,it isrecommended that where feasible, a shield connected to cathode potential, be placed aroundand in contact with the glass envelope of the photomultiplier.
The PMT should be degaussed before using, and a magnetic shield should be employed.Note that even the earth’s magnetic field is of sufficient strength to influence measurements.Tube temperature should preferably be maintained constant at ± 2 °C within the limits from19 °C to 25 °C. This is important in instances where the voltage divider may raise thetemperature of the test enclosure.
Caution should be used to avoid drifts or base line shifts in the electronic circuitry thatsignificantly affects the measurements.
To prevent drifts or base line shifts in potentials between dynodes resulting from the electronmultiplier current,the quiescent current drawn by the resistive voltage divider should be at
least 20 times the DC anode current.Alternatively,the potentials between dynodes for thedynodes drawing the greatest current may be individually stabilized (as with separate powersupplies).
Charge-storage capacitors may be effectively used across the dynodes or from the dynodesto ground when the ratio of the peak anode current to the average anode current is large andthe capacitor can maintain the required dynode potentials for the duration of the pulse.
Pulse shaping methods and time constants suitable for optimum performance should be usedand should be stated.
5 Test procedures for photomultiplier characteristics
5.1 General
ln addition to the specifications and test methods of lEC 60306-4, complementary or extendedspecifications and tests required for photomultipliers used with scintillation and Cherenkovdetectors are:
a)Pulse height characteristics1.b)Dark current.
)Pulse timing characteristics.5.2 Pulse height characteristics5.2.1General
Pulse height is used in counting and spectrometric applications.
5.2.2 Pulse height resolution measurement
ln general there are four distinct PHR measurements to define the photon-and-electronresolution of PMT and scintillator/PMT combinations. These resolutions may be usedseparately or together. PHR for a scintillator/PMT combination
This PHR is a function of the photocathode quantum efficiency, collection efficiencies of thedynodes and spatial uniformity, as well as the resolution of the scintillator.