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CHARGE TERMINATOR A specially constructed
terminator is mounted in a rear-panel clip and
should be used to properly terminate the pulser
output and feed a charge signal into the signal input
of a charge-sensitive preamplifier when the output
pulses are being furnished for this type of test.
ELECTRICAL AND MECHANICAL
POWER REQUIREMENTS +24 V, 45 mA; -24 V,
25 mA; + 12 V, 0 mA; - 12 V, 5 mA; 115 V ac,
10 mA.
3.1. GENERAL
The 419, used in conjunction with a 4001A/4002A
Bin and Power Supply, is intended for rack
mounting, and therefore any vacuum tube
equipment operating in the same rack must be
sufficient cooled by circulating air to prevent any
localized heating of the all-transistor circuitry used
throughout the 419 and the 4001A/4002A. The
temperature of equipment mounted in racks can
easily exceed 120°F (50°C) unless precautions are
taken. The 419 should not be subjected to
temperatures in excess of 120°F (50°C).
3.2. CONNECTION TO POWER
The 419 contains no internal power supply and
must obtain power from a nuclear standard bin and
power supply, such as the ORTEC 4001A/4002A.
It is recommended that the bin power supply be
turned off when modules are inserted or removed.
The ORTEC 4001A/4002A has test points on the
power supply control panel to monitor the dc
voltages. When using the 419 outside the
4001A/4002A Bin and Power Supply, be sure that
the power jumper cable used properly accounts for
the power supply grounding circuits provided in the
recommended standards of US DOE TID-20893
(Rev.). Both high-quality and power-return ground
connections are provided to ensure proper
reference voltage feedback into the power supply,
and these must be preserved in remote cable
installations. Be careful to avoid ground loops when
the module is operated outside the bin.
If the 419 is inserted in a bin which has no ac
voltage, the unit will operate correctly on the INT.
OSC position of the RELAY switch.
3
DIMENSIONS Standard double-width NIM module
(2.70 in. wide by 8.714 in. high) per TID-20893
(Rev.).
SHIPPING WEIGHT 6.5 lb (2.95 kg).
NET WEIGHT 4.5 lb (2.kg).
3. INSTALLATION
3.3. USE OF EXTERNAL REFERENCE
VOLTAGE - EXTERNAL/INTERNAL
The BNC connector on the rear panel provides for
the use of an external reference voltage in the 419.
The external reference voltage can be of any
arbitrary waveshape, either dc or an arbitrary
function such as a linear ramp function or any other
waveform. The absolute magnitude of this voltage
should not exceed 20 V, due to the power rating of
the resistors in the pulse-forming network inside the
419. When using a reference voltage other than a
constant dc value, ensure that the rate of change of
the arbitrary waveform is slow with respect to the
chopping frequency of the mercury-wetted relay in
the 419. If the waveform of an input signal is much
faster than the chopping frequency of the relay,
considerable distortion in the output pulse
amplitude will occur.
Reference to Drawing 419-0201-S1 will show that
the use of an external reference voltage will cause
the POLARITY and NORMALIZE controls to be
ineffective when the INT-EXT switch is in the EXT
position. Of course, when the switch is placed back
to INT reference, the controls will again have their
control function.
CONNECTIONS AND TERMINATING
IMPEDANCE CONSIDERATIONS
There are three general methods of termination
that are used. The simplest of these is shunt
termination at the receiving end of the cable. A
REFERENCE SWITCH
3.4. LINEAR OUTPUT SIGNAL
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