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Kentech Instruments Ltd., Isis Building, Howbery Park, Wallingford, Oxfordshire, OX10 8BD, U.K.
Last Modified 11-2-20
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OPERATION OF THE PULSER
7.1 GENERAL OPERATION
The pulser requires 12 volts D.C. power and a trigger signal to operate. The trigger signal applied
to the rear panel trigger input (BNC) should be 5V into 50Ω with a fast rising edge (<5ns) to
maintain the low jitter of the system. When triggered the triggered light on the rear panel will
flash.
The output of the unit is a nominal 3.6kV positive pulse which appears at the output front panel
connector (N type). The pulse width is fixed at ~4ns.
If it is necessary to monitor or characterise the pulse output then suitable attenuators should be
used.
Note that the supply voltage should be 12 volts at the input to the unit. If long power leads are
used these may cause enough voltage drop to reduce the voltage at the pulser to < 12 volts. A
slightly higher supply should then be used. If the unit is operated at less than about 11.9 volts the
output amplitude may be reduced and the trigger delay increased.
Also note that the unit is fitted with a 13 volt zener diode which will protect the input against too
high a voltage for a limited time. Do not leave more than 13 volts on the unit for an extended
time or the zener diode might fail.
For future units we are considering a built in voltage regulator and more protection to improve
the tolerance to the wrong input voltage.
CAUTION
The output of this unit will damage or destroy many types of high voltage and high power
attenuators. We only recommend the use of a high voltage, high speed attenuator manufactured
by Barth™ as the first in a series. Consult the attenuator manufacturer before using any other
configuration.
The output may be observed with a high bandwidth oscilloscope. This may either be a fast
(>3GHz) direct access type or a sampling type.
The trigger delay from trigger input BNC to main output is approximately 20ns. The jitter is
~20ps peak to peak with a suitably reproducible and fast rising trigger signal.
