EG&G ORTEC 553 Manuel d'utilisation et d'entretien - Page 8
Parcourez en ligne ou téléchargez le pdf Manuel d'utilisation et d'entretien pour {nom_de_la_catégorie} EG&G ORTEC 553. EG&G ORTEC 553 16 pages. Timing single-channel analyzer
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INSTALLATION
The 553 must be used in conjunction with an ORTEC
401/402 Series Bin and Power Supply or equivalent,
which is intended for rack mounting. Therefore if
vacuum tube equipment or any other source of heat is
operating in the same rack, there must be sufficient
cooling air circulating to prevent any localized heating of
the transistorized and integrated circuits used through
out the 553. The temperature of equipment mounted in
racks can easily exceed the maximum unless precau
tions are taken; the 553 should not be subjected to
temperatures in excess of 120°F (50°C).
3.1.
CONNECTION TO POWER
Turn off the Bin Power Supply when inserting or remov
ing modules. The ORTEC NIM modules are designed so
that it is not possible to overload a properly operating
power supply with a full complement of modules in the
bin. Since, however, this may not be true when the bin
contains modules other than those of ORTEC design,
power supply voltages should be checked after the
modules have been inserted. The 401/402 has test points
on the power supply control panel to monitor dc
voltages.
When using the 553 outside the 401/402 Bin and Power
Supply, be sure that the power extension cable that is
used properly accounts for the power supply grounding
circuits that are provided according to the recommended
ERDA standards outlined in TID-20893 (Rev). Both high-
quality and power-return ground connections are pro
vided to ensure proper reference voltage feedback into
the power supply, and these must be preserved in remote
cable installations. Be careful also to avoid ground loops
when the module is operated outside the bin.
3.2.
CONNECTION FROM LINEAR AMPLIFIER
The 553 can be used for the analog signals that are
furnished from a linear amplifier. The BNC on the front
panel accepts input signals through a dc-coupled path.
The input circuit accepts positive unipolar pulses or
bipolar pulses (the positive lobe will be analyzed) into an
input impedance of ^lOOOfl. When long cables (more
than about 4 ft) are used to connect the amplifier output
to the 553 input, cable termination may be necessary in
order to prevent reflections; match the cable impedance
with a terminator at the 553 input in such cases.
3.3.
OUTPUT CONNECTIONS
The logic output pulses that are generated when input
pulses satisfy the amplitude and logic requirements of
the 553 are available through both front and rear panel
BNC connectors. NIM-standard fast negative signals are
available through the front panel Neg Out BNC. NIM-
standard slow positive signals are available through the
front panel Pos Out connector.
When the 553 is set for either differential single-channel
mode (normal or window), the logic output pulse means
that an input pulse amplitude is sufficient to trigger the
lower level discriminator without also triggering the
upper level discriminator. When the 553 is set for its
integral mode of operation, the logic output means that
an input pulse amplitude is sufficient to trigger the lower
level discriminator; triggering of the upper level discrimi
nator does not affect the output.
The time when both SCA logic output signals are made
available is the result of an internal strobe. The strobe
originates from the constant-fraction trigger, at 50%
amplitude on the decay of the positive input pulse. This
strobes a delay circuit, with the delay interval adjusted
with a front panel control between 0.1 and 1.1 ^s, and the
outputs occur at the end of the delay interval.
A logic output is available through the rear panel to
indicate when, on the leading edge of an input pulse, the
UL discriminator is triggered. These responses can be
used to monitor the discriminator levels during adjust
ment, to be counted in external sealers, to provide
subgroup routing in a multichannel analyzer, or for any
other applications as desired. Each logic output for UL
Out is a NIM-standard slow positive pulse that is com
patible with all ORTEC counters, counting rate meters,
and other instruments. The output impedance through
each output path is sufficiently low to drive as many as
ten paralleled lOOOH inputs.
3.4.
LOWER LEVEL REFERENCE INPUT
If the LL Ref toggle switch on the rear panel of the 553 is
set at Ext, the reference level for the lower level discrimi
nator must be furnished through the adjacent LL Ref In
BNC connector; the 10-turn Lower Level control on the
front panel is disconnected. An input of 0 to -10 V
through this connector corresponds directly to a range
of 0 to +10 V for the lower level discriminator threshold.
If an input is connected to the LL Ref connector and the
switch selects Int, the signal through the connector is
ignored.