Model 2363
Technical Manual
Section 8
Ludlum Measurements, Inc.
Page 8-1
January 2015
Technical Theory of Operation
Gamma
Transistor pairs, U9 and U10, form the charge sensitive amplifier. U13,
comparator with 0.23 Vdc threshold, produces negative-going 5-volt pulses
for every valid gamma pulse. One-shot, U15A provides single pulses for each
event
Gamma HV
Switching of U17 sends 5-volt pulses through step-up transformer T2. Diode
and capacitor multiplying ladder produces 550 Vdc, regulated by feedback
voltage through R47.
Neutron
Transistor pairs, U11, and U12 form the charge sensitive amplifier. U14
comparator with 0.23 Vdc threshold produces negative-going 5-volt pulses
for every valid neutron pulse. One-shot, U15B produces single pulses for each
event.
Neutron HV
Switching of U18 sends 5-volt pulses through step-up transformer T3. Diode
and capacitor multiplying ladder produces high voltage, regulated by feedback
voltage through R48 and controlled by
NHV
potentiometer R55.
Low Voltage Power Supply
U16 step-up regulator (LT1304) switches battery voltage through inductor L1
to produce reg5 Vdc. Resistor divider R32 and R49 provide input for
low-battery signal, which is sent to the microprocessor.
Section
8