ORTEC 418A Service manual
QfJYEC^
r^/si<s
20of
Model
418A
Universal
Coincidence
Operating
and
Service
Manual
S/V
Z/
/"V
US"
^09/r
Model
418A
Universal
Coincidence
Operating
and
Service
Manual
Printed
In
U.S.A.
ORTECf
Part
No.
733170
1202
Manual
Revision
B
Advanced
Measurement
Technology,
inc.
a/k/a/
ORTEC®,
a
subsidiary
of
AMETEK®,
Inc.
WARRANTY
ORTEC*
warrants
that
the
items
will
be
delivered
free
from
defects
in
material
or
workmanship.
ORTEC
makes
no
other
warranties,
express
or
implied,
and
specifically
NO
WARRANTY
OF
MERCHANTABILITY
OR
FITNESS
FOR
A
PARTICULAR
PURPOSE.
ORTEC's
exclusive
liability
is
limited
to
repairing
or
replacing
at
ORTEC's
option,
items
found
by
ORTEC
to
be
defective
in
workmanship
or
materials
within
one
year
from
the
date
of
delivery.
ORTEC's
liability
on
any
claim
of
any
kind,
including
negligence,
loss,
or
damages
arising
out
of,
connected
with,
or
from
the
performance
or
breach
thereof,
or
from
the
manufacture,
sale,
delivery,
resale,
repair,
or
use
of
any
item
or
services
covered
by
this
agreement
or
purchase
order,
shall
in
no
case
exceed
the
price
allocable
to
the
item
or
service
furnished
or
any
part
thereof
that
gives
rise
to
the
claim.
In
the
event
ORTEC
fails
to
manufacture
or
deliver
items
called
for
in
this
agreement
or
purchase
order,
ORTEC's
exclusive
liability
and
buyer's
exclusive
remedy
shall
be
release
of
the
buyer
from
the
obligation
to
pay
the
purchase
price.
In
no
event
shall
ORTEC
be
liable
for
special
or
consequential
damages.
Quality
Control
Before
being
approved
for
shipment,
each
ORTEC
instrument
must
pass
a
stringent
set
of
quality
control
tests
designed
to
expose
any
flaws
in
materials
or
workmanship.
Permanent
records
of
these
tests
are
maintained
for
use
in
warranty
repair
and
as
a
source
of
statistical
information
for
design
improvements.
Repair
Service
If
it
becomes
necessary
to
return
this
instrument
for
repair,
it
is
essential
that
Customer
Services
be
contacted
in
advance
of
its
return
so
that
a
Return
Authorization
Number
can
be
assigned
to
the
unit.
Also,
ORTEC
must
be
informed,
either
in
writing,
by
telephone
[(865)
482-4411]
or
by
facsimile
transmission
[(865)
483-2133],
of
the
nature
of
the
fault
of
the
instrument
being
returned
and
of
the
model,
serial,
and
revision
("Rev"
on
rear
panel)
numbers.
Failure
to
do
so
may
cause
unnecessary
delays
in
getting
the
unit
repaired.
The
ORTEC
standard
procedure
requires
that
instruments
returned
for
repair
pass
the
same
quality
control
tests
that
are
used
for
new-production
instruments.
Instruments
that
are
returned
should
be
packed
so
that
they
will
withstand
normal
transit
handling
and
must
be
shipped
PREPAID
via
Air
Parcel
Post
or
United
Parcel
Service
to
the
designated
ORTEC
repair
center.
The
address
label
and
the
package
should
include
the
Return
Authorization
Number
assigned.
Instruments
being
returned
that
are
damaged
in
transit
due
to
inadequate
packing
will
be
repaired
at
the
sender's
expense,
and
it
will
be
the
sender's
responsibility
to
make
claim
with
the
shipper.
Instruments
not
in
warranty
should
follow
the
same
procedure
and
ORTEC
will
provide
a
quotation.
Damage
in
Transit
Shipments
should
be
examined
immediately
upon
receipt
for
evidence
of
external
or
concealed
damage.
The
carrier
making
delivery
should
be
notified
immediately
of
any
such
damage,
since
the
carrier
is
normally
liable
for
damage
in
shipment.
Packing
materials,
waybills,
and
other
such
documentation
should
be
preserved
in
order
to
establish
claims.
After
such
notification
to
the
carrier,
please
notify
ORTEC
of
the
circumstances
so
that
assistance
can
be
provided
in
making
damage
claims
and
in
providing
replacement
equipment,
if
necessary.
Copyright
©
2002,
Advanced
Measurement
Technology,
Inc.
All
rights
reserved.
*ORTEC®
is
a
registered
trademark
of
Advanced
Measurement
Technology.
Inc.
All
other
trademarks
used
herein
are
the
property
of
their
respective
owners.
Ill
CONTENTS
WARRANTY
ii
SAFETY
INSTRUCTIONS
AND
SYMBOLS
v
SAFETY
WARNINGS
AND
CLEANING
INSTRUCTIONS
vi
1.
DESCRIPTION
1
1.1.
GENERAL
1
1.2.
BASIC
FUNCTION
1
2.
SPECIFICATIONS
1
3.
INSTALLATION
2
3.1.
GENERAL
2
3.2.
CONNECTION
TO
POWER
2
3.3.
LOGIC
INPUTS
TO
THE
COINCIDENCE
UNIT
2
4.
OPERATING
INSTRUCTIONS
3
4.1.
FRONT
PANEL
CONTROLS
3
4.2.
CONNECTOR
DATA
3
4.3.
INITIAL
TESTING
AND
OBSERVATION
OF
PULSE
WAVEFORMS
3
4.4.
TYPICAL
OPERATING
CONSIDERATIONS
3
5.
CIRCUIT
DESCRIPTION
4
5.1.
INPUT
A
5
5.2.
INPUTS
B,C,D,
and
E
5
6.
CALIBRATION
AND
MAINTENANCE
6
6.1.
TESTING
PERFORMANCE
OF
SLOW
COINCIDENCE
6
6.2.
SUGGESTIONS
FOR
TROUBLESHOOTING
8
6.3.
TABULATED
TEST
POINT
VOLTAGES
ON
ETCHED
BOARD
8
^
#
r
o
Kk
IpJ
Al
SAFETY
INSTRUCTIONS
AND
SYMBOLS
This
manual
contains
up
to
three
levels
of
safety
instructions
that
must
be
observed
in
order
to
avoid
personal
injury
and/or
damage
to
equipment
or
other
property.
These
are:
DANGER
Indicates
a
hazard
that
could
result
in
death
or
serious
bodily
harm
if
the
safety
instruction
is
not
observed.
WARNING
Indicates
a
hazard
that
could
result
in
bodily
harm
if
the
safety
instruction
is
not
observed.
CAUTION
Indicates
a
hazard
that
could
result
in
property
damage
if
the
safety
instruction
is
not
observed.
Please
read
all
safety
instructions
carefully
and
make
sure
you
understand
them
fully
before
attempting
to
use
this
product.
In
addition,
the
following
symbol
may
appear
on
the
product:
ATTENTION-Refer
to
Manual
A
DANGER-Hlgh
Voltage
Please
read
all
safety
instructions
carefully
and
make
sure
you
understand
them
fully
before
attempting
to
use
this
product.
VI
SAFETY
WARNINGS
AND
CLEANING
INSTRUCTIONS
DANGER
Opening
the
cover
of
this
instrument
is
likely
to
expose
dangerous
voltages.
Disconnect
the
instrument
from
all
voltage
sources
while
it
is
being
opened.
WARNING
Using
this
instrument
in
a
manner
not
specified
by
the
manufacturer
may
impair
the
protection
provided
by
the
instrument.
Cleaning
Instructions
To
clean
the
instrument
exterior:
•
Unplug
the
instrument
from
the
ac
power
supply.
•
Remove
loose
dust
on
the
outside
of
the
instrument
with
a
lint-free
cloth.
•
Remove
remaining
dirt
with
a
lint-free
cloth
dampened
in
a
general-purpose
detergent
and
water
solution.
Do
not
use
abrasive
cleaners.
CAUTION
To
prevent
moisture
inside
of
the
instrument
during
external
cleaning,
use
only
enough
liquid
to
dampen
the
cloth
or
applicator.
•
Allow
the
instrument
to
dry
completely
before
reconnecting
it
to
the
power
source.
ORTEC
MODEL
418A
UNIVERSAL
COINCIDENCE
1.
DESCRIPTION
1.1.
GENERAL
The
ORTEC
418A
is
a
coincidence
unit
with
five
inputs.
Each
input
has
a
three-position
switch
associated
with
it
to
select
the
COINCIDENCE,
ANTICOINCIDENCE,
or
OFF
mode.
The
resolving
time
of
Input
A
is
controlled
by
a
front-panel
potentiometer
and
is
continuously
variable
from
100
ns
to
2
ps.
The
remaining
four
inputs
are
de
coupled
and
their
resolving
times
are
determined
by
their
input
pulse
widths.
By
means
of
a
front-panel
switch
1,2,3,4,
or
5
coincident
pulses
may
be
required
for
an
output
and
all
five
inputs
are
used
in
the
coincident
mode,
an
output
pulse
w
ill
be
obtained
when
a
coincident
occurs
between
anv
two
inputs.
Input
A
is
particularly
useful
for
anticoincidence
and
coincidence
strobe
operations
because
of
its
variable
resolving
time;
e.g.,
this
input
can
be
used
in
the
anticoincidence
m
ode
to
block
two
500-ns-wide
input
pulses
without
additional
external
pulse-shaping
equipment.
Two
positive
output
pulses
are
provided
on
BNC
connectors,
one
front
panel
and
one
rear
panel.
These
pulses
are
normally
500
ns
wide
but
their
width
can
be
altered
as
desired
by
changing
a
capacitor.
1.2.
BASIC
FUNCTION
The
418A
employs
an
"overlap"
type
of
coincidence
circuit.
Each
input
pulse
is
regenerated
into
a
current
pulse
which
has
a
fast
rise
and
fall
time.
These
current
pulses
are
fed
into
an
AND
circuit
which
produces
an
output
when
an
overlap
occurs.
The
width
of
the
current
pulse
from
Input
A
is
controlled
by
a
front-panel
potentiometer
and
can
be
varied
from
100
ns
to
2
jJs.
The
current
pulses
from
the
remaining
inputs
are
the
same
width
as
their
associated
input
pulses
at
the
1.8-V
level.
Since
these
inputs
are
dc-coupled,
their
current
pulses
can
be
made
infinitely
long
by
the
application
of
a
dc
voltage
to
the
input.
The
routing
of
the
individual
current
is
controlled
by
front-panel
toggle
switches.
They
can
be
routed
to
the
COINCIDENCE
or
AND
circuit,
ground
(OFF
position),
or
the
ANTICOINCIDENCE
circuit.
The
front-panel
COINCIDENCE
REQUIREMENTS
switch
alters
the
AND
circuits
so
that
1,2,3,4,
or
5
coincident
current
pulses
are
required
to
produce
an
output:
therefore
the
number
of
INPUT
CONTROL
toggle
switches
in
the
COINCIDENCE
position
must
be
equal
to
or
greater
than
the
number
selected
by
the
COINCIDENCE
REQUIREMENTS
switch
in
order
for
the
unit
to
produce
an
output.
A
current
pulse
routed
to
the
anticoincidence
circuit
blocks
all
pulses
routed
to
the
coincidence
circuit
for
the
duration
of
the
anticoincidence
pulse.
When
the
coincidence
requirements
are
met,
a
500-ns-wide
output
pulse
is
generated.
The
width
of
this
pulse
can
be
changed
as
desired
by
changing
the
value
of
capacitor
C9.
2.
SPECIFICATIONS
The
418A
is
housed
in
a
Nuclear
Standard
Module.
It
is
one
module
wide
and
weighs
1.5
lb.
It
contains
no
internal
power
supply
and
must
therefore
obtain
the
necessary
operating
power
from
the
Nuclear
Standard
Bin
and
Power
Supply,
ORTEC
4001A/4002A.
All
signals
in
and
out
of
the
module
are
on
front-panel
BNC
connectors,
and
an
additional
output
BNC
is
on
the
rear
panel.
PERFORMANCE
RESOLVING
TIME
(T).
INPUT
A
100
ns
to
2
[Js
controlled
by
20-turn
potentiometer.
INPUTS
B,C,D,E,
Controlled
by
input
pulse
width.
COINCIDENCE
REQUIREMENTS
Selectable
by
front-panel
switch;
i.e.,
1,
2,
3,
4,
or
5
coincident
pulses
may
be
required
to
yield
an
output.
For
example,
if
the
COINCIDENCE
REQUIREMENTS
switch
is
set
to
3
and
all
five
INPUT
CONTROL
switches
are
set
to
COINCIDENCE,
an
output
will
be
obtained
when
a
coincidence
occurs
between
anv
three
inputs.
INPUTS
POLARITY
Positive
2
V
minimum,
30
V
maximum.
PULSE
WIDTH
50
ns
to
dc.
IMPEDANCE
>1.5kQ,
dc-coupled
OUTPUTS
TEMPERATURE
STABILITY
Change
in
INPUT
A
resolving
time
(T)
is
less
than
0.1
%rC;
change
in
INPUTS
B,
C,
D,
and
E
resolving
time
(T)
is
less
than
0.5%/°C;
T
=
500
ns.
Two
each,
dc-coupled,
positive
5
V,
500
ns
wide;
impedance
<10Q.
MECHANICAL
AND
ELECTRICAL
OPERATING
TEMPERATURE
0
to
50°C.
CONTROLS
(INPUTS)
Each
input
has
a
three-position
locking
toggle
switch
associated
with
it
which
permits
any
input
to
be
used
in
the
COINCIDENCE,
ANTICOINCIDENCE,
or
OFF
mode.
When
the
OFF
mode
is
selected,
the
respective
input
is
disabled.
MECHANICAL
One
module
wide
and
designed
to
meet
the
recommended
interchangeab
ility
standards
set
forth
in
DOE
Report
TID-20893
(Rev.);
1.35
in.
Wide,
8.714
in.
High,
and
9.75
in.
Long.
POWER
REQUIREMENTS
+24
V,
105
mA;
+12
V,
50
mA;
-24
V,
90
mA;
-12
V,
30
mA.
3.
INSTALLATION
3.1.
GENERAL
The
418A,
used
in
conjunction
with
a
4001A/4002A
Bin
and
Power
Supply,
is
intended
for
rack
mounting;
therefore
any
vacuum
tube
equipment
operating
in
the
same
rack
must
be
sufficiently
cooled
with
circulating
air
to
prevent
any
localized
heating
of
the
all-transistor
circuitry
used
throughout
the
418A.
The
temperature
of
the
equipment
mounted
in
racks
can
easily
exceed
the
recommended
maximum
of
120°F
(50°C)
unless
precautions
are
taken.
3.2.
CONNECTION
TO
POWER
Because
the
418A
contains
no
internal
power
supply,
it
must
obtain
operating
power
from
the
Nuclear
Standard
Bin
and
Power
Supply
such
as
ORTEC
4001A/4002A.
It
is
recommended
that
the
bin
power
supply
be
turned
off
when
modules
are
inserted
or
removed.
The
ORTEC
NIM
modules
are
designed
so
that
it
is
not
possible
to
overload
the
NIM
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
are
inserted.
ORTEC
4001A/4002A
has
test
points
on
the
power
supply
control
panel
to
monitor
the
dc
voltages.
3.3.
LOGICINPUTS
TO
THE
COINCIDENCE
UNIT
The
input
pulses
to
the
418A
may
come
from
any
source
of
logic
pulses.
The
input
impedance
is
approximately
2000Q,
and
some
care
must
be
given
to
ensure
that
reflections
do
not
occur
in
the
driving
transmission
cable.
Reflections
can
probably
best
be
avoided
by
terminating
the
driving
cable
at
the
inputs
with
the
characteristic
impedance
of
the
driving
cable.
The
amplitude
and
width
of
the
input
signals
are
specified
in
Section
2.2.
4.
OPERATING
INSTRUCTIONS
4.1.
FRONT
PANEL
CONTROLS
INPUT
A
RESOLVING
TIME
CONTROL
Each
input
pulse
is
regenerated
into
a
current
pulse
with
fast
rise
and
fall
times.
The
width
of
the
current
pulse
from
INPUT
A
is
continuously
variable
from
100
ns
to
2
fJ.
The
current
pulses
from
the
remaining
inputs
are
the
same
width
of
these
current
pulses
at
the
1.8-V
level.
The
width
of
these
current
pulses
determines
the
resolving
time
of
the
unit.
INPUT
A
RESOLVING
TIME
control
is
especially
useful
when
INPUT
A
is
used
in
the
anticoincidence
mode;
e.g.,
this
input
can
be
used
to
block
two
500-ns-wide
pulses
without
additional
external
pulse
shaping
equipment.
COINCIDENCE
REQUIREMENTS
The
position
of
this
switch
determines
the
number
of
coincidence
pulses
required
to
produce
an
output
pulse;
e.g.,
if
this
switch
is
in
the
2
position
and
all
input
control
switches
are
in
the
COINCIDENCE
position,
an
output
pulse
will
be
pr
educed
when
any
two
input
pulses
are
in
coincidence.
In
order
to
obtain
an
output
pulse,
the
number
of
input
control
switches
in
the
COINCIDENCE
position
must
always
be
equal
to
or
greater
than
the
number
of
selected
by
the
COINCIDENCE
REQUIREMENTS
switch.
INPUT
CONTROLS
Each
of
the
five
three-position
locking
toggle
switches
determines
the
routing
of
the
signal
applied
to
its
associated
input
connector.
The
three
positions
of
each
switch
and
their
function
are:
1.
COINCIDENCE
-
Input
signal
is
routed
to
the
coincidence
portion
of
the
circuit.
2.
OUT
-
Input
signal
is
routed
to
ground;
therefore
it
does
not
affect
the
coincidence
or
anticoincidence
portion
of
the
circuit
and
is
completely
out
of
the
system.
3.
ANTICOINCIDENCE
-
Input
signal
is
routed
to
the
anticoincidence
portion
of
the
circuit
and
will
block
all
coincidence
signals
for
the
duration
of
the
anticoinicdence
signal,
except
for
INPUT
A,
for
which
the
blocking
time
is
a
function
of
the
front-
panel
RESOLVING
TIME
control.
Any
combination
of
switch
positions
may
be
used;
however,
an
output
pulse
can
be
obtained
onlv
when
the
number
of
input
controls
in
the
COINCIDENCE
positions
is
equal
to
or
exceeds
the
number
selected
by
the
COINCIDENCE
REQUIREMENTS
switch.
4.2.
CONNECTOR
DATA
INPUT
A
is
a
front-panel
BNC
connector
de
coupled
to
the
internal
circuitry
and
has
an
impedance
to
ground
greater
than
1.5
kO.
To
minimize
reflections
when
driving
from
a
low-
impedance
source
into
this
connector,
a
terminator
equal
to
the
characteristics
impedance
of
the
driving
cable
should
be
shunted
to
ground.
A
positive
2-V
signal
with
a
minimum
width
of
50
ns
is
required
to
trigger
the
input
circuit.
The
resolving
time
of
INPUT
A
can
be
varied
from
ICQ
ns
to
2
|J
by
the
INPUT
A
RESQLVING
TIME
control.
INPUTS
B,C,D,E
-
Same
as
INPUT
A,
except
that
the
resolving
time
is
set
by
the
input
pulse
width.
OUTPUTS
Two
separate,
buffered,
dc-coupled
coincidence
outputs
are
provided
on
BNC
connectors.
The
output
pulses
are
5
V
in
amplitude
and
500
ns
wide.
The
output
pulse
width
can
be
altered
as
desired
by
changing
capacitor
09.
The
amplitude
can
be
increased
by
increasing
the
value
of
R75.
TEST
POINT
An
oscilloscope
test
point
is
provided
for
monitoring
the
output
signals.
The
test
point
has
a
470Q
resistor
connecting
it
to
the
associated
BNC
output
connector
on
the
front
panel.
4.3.
INITIAL
TESTING
AND
OBSERVATION
OF
PULSE
WAVEFORMS
Refer
to
Section
6
for
information
on
testing
performance
and
observing
waveforms.
4.4.
TYPICAL
OPERATING
CONSIDERATIONS
The
coincidence
circuit
is
an
overlap
type
or
it
can
be
described
as
an
AND
circuit.
The
2
T
resolving
time
of
INPUT
A
is
determined
by
the
INPUT
A
RESQLVING
TIME
control.
See
timing
diagrams
in
Figs.
4.1
through
4.5.
If
the
coincidence
requirements
are
met
by
the
input
pulses,
two
standard
output
pulses
500
ns
wide
and
5
V
in
amplitude
are
produced
regardless
of
the
overlap
time
of
the
coincident
pulses.
The
width
of
the
output
pulses
may
be
changed
by
changing
the
value
of
C9.
Careful
attention
should
be
given
the
418A
front-
panel
controls
when
using
it.
The
input
control
toggle
switches
determine
the
routing
of
each
input
pulse.
The
COINCIDENCE
REQUIREMENTS
switch
determines
the
number
of
coincident
pulses
required
to
yield
an
output
pulse.
This
means
that
the
number
of
input
control
switches
in
the
COINCIDENCE
position
must
be
equal
to
or
greater
than
the
number
selected
by
the
COINCIDENCE
REQUIREMENTS
switch
(see
Fig.
4.5).
J
L
^
INPUT
B
COINCIDENCE
MODE
„
INPUT
C
COINaDENCE
MODE
^OUTPUT
Fig.
4.1.
Coincidence
Requirements
When
Switch
Setting
Is
2.
JT
r~
rr
.
INPUT
A
COINODENCE
MODE
INPUT
A
INTERNAL
-
REGENERATED
CURRENT
PULSE
_
INPUT
0
COINaDENCE
MODE
.
OUTPUT
Fig.
4.2.
Coincidence
Requirements
When
Switch
Setting
Is
2.
.
INPUT
B
ANTI-COINCIDENCE
MODE
.
INPUT
C
COINaDENCE
MODE
.
INPUT
D
COINCIDENCE
MODE
.
INPUT
E
a}INC10ENCE
MODE
.OUTPUT
Fig.
4.3.
Coincidence
Requirements
When
Switch
Setting
Is
3.
.
INPUT
B
ANTI
COINCIDENCE
MODE
.
INPUT
C
COINCIDENCE
MODE
.
INPUT
D
COINCIDENCE
MODE
,
OUTPUT
Fig.
4.4.
Coincidence
Requirements
When
Switch
Setting
Is
2.
J
L
J
L
.
INPUT
B
COINaDENCE
MODE
.
INPUT
C
COINCIDENCE
MODE
_
input
d
coinodence
mode
.
OUTPUT
200485
Fig.
4.5.
Coincidence
Requirements
When
Switch
Setting
Is
4.
5.
CIRCUIT
DESCRIPTION
The
418A
has
five
dc-coupled
inputs
which
may
be
used
in
the
coincidence
or
anticoincidence
mode.
Each
input
is
protected
by
a
diode
limiter.
INPUT
A
has
a
variable
resolving
time,
while
INPUTS
B
through
E
have
a
resolving
time
determined
by
their
input
pulse
widths.
The
input
controls
route
the
signals
from
these
inputs
to
the
coincidence
(CR29)
or
anticoincidence
(025)
stage.
The
number
of
coincident
pulses
required
to
trigger
the
coincidence
stage
(tunnel
diode
CR29)
is
determined
by
the
amount
of
reverse
current
flowing
in
CR29.
The
quiescent
current
flowing
in
CR29
is
controlled
by
the
COINCIDENCE
REQUIREMENTS
switch
and
026.
If
CR29
is
triggered
to
its
high
state,
a
one
shot
(Q27-Q29)
is
triggered
which
produces
a
5-V
500-ns-wide
pulse.
This
pulse
is
passed
through
two
emitter
followers
to
the
output
connectors.
5.1.
INPUT
A
INPUT
A
is
fed
to
a
current
switch
(01
and
03)
through
a
diode
limiter
consisting
of
CR1,
CR2,
R1,
R2,
R3,
and
R4.
The
limiting
action
is
accomplished
when
a
positive
voltage,
large
enough
to
switch
the
constant
current
that
normally
flows
through
CR1
and
Rl
to
the
limiter
load,
R3
and
R4,
is
applied
to
the
input.
This
causes
the
01
base
voltage
to
exceed
ground
potential
and
turn
01
on.
Emitter
follower
02
drives
the
base
of
06
negative
through
the
timing
capacitor,
C2,
with
the
pulse
from
the
collector
of
01.
The
resolving
time
of
INPUT
A,
T,,
is
determined
by
the
length
of
time
that
06
is
off.
The
constant
current
generator,
04,
controls
the
off
time
of
06,
by
discharging
capacitor
C2
back
from
its
negative
value
toward
ground.
When
the
voltage
at
the
base
of
06
exceeds
ground
potential,
06
is
turned
on
again.
08
converts
the
voltage
pulse
at
06
collector
to
a
current
pulse
to
drive
the
coincidence
stage.
05
is
used
as
a
feedback
element
to
ensure
that
the
pulse
from
the
input
current
switch,
01
collector,
has
a
minimum
duration
of
regardless
of
the
input
pulse
width.
5.2.
INPUTS
B,C,D,
and
E
These
four
inputs
are
identical,
so
only
INPUT
B
will
be
explained.
A
diode
limiter
similar
to
that
of
INPUT
A
is
provided.
This
limiter
is
followed
by
a
dc
Schmitt
trigger
circuit,
09,
O10,
011.
In
the
quiescent
state
the
base
of
09
is
at
ground
potential
and
the
base
of
OlO
is
1.8
V.
The
010
base
potential
is
maintained
by
the
current
from
011
and
R25.
When
a
pulse
is
applied
to
the
input
and
raises
the
base
of
09
above
the
potential
at
the
base
of
OlO,
09
turns
on
and
010
and
01II
turn
off.
Due
to
the
loss
of
the
current
supplied
by
011,
the
base
of
OlO
is
now
set
at
0.9
V.
The
circuit
will
be
reset
to
its
quiescent
state
when
the
input
voltage
drops
below
0.9
V.
The
hysteresis
and
threshold
of
the
circuit
can
be
altered
by
changing
the
value
of
R22
and
R25.
012
converts
the
voltage
pulse
at
the
collector
of
OlO
to
a
current
pulse.
The
current
pulse
from
each
input
circuit
is
connected
to
a
three-position
toggle
switch
(input
controls)
which
routes
the
pulse
to
the
coincidence
stage,
ground
(OUT
position),
or
the
anticoincidence
stage.
The
anticoincidence
stage
is
composed
of
025,
which
is
biased
off
in
the
quiescent
condition.
An
anticoincidence
pulse
saturates
025
for
the
duration
of
the
pulse.
When
025
saturates,
it
short
circuits
the
coincidence
line
to
ground,
thereby
preventing
coincidence
signals
from
reaching
the
coincidence
stage
for
the
duration
of
the
anticoincidence
pulse.
The
coincidence
stage
is
composed
of
CR29
and
026.
When
tunnel
diode
CR29
is
set
to
its
high
state
by
the
coincidence
current
pulses,
the
418A
produces
an
output
pulse.
The
number
of
coincident
current
pulses
required
to
set
CR29
to
its
high
state
is
determined
by
its
quiescent
current.
The
bias
current
in
CR29
is
equal
to
the
collector
current
of
026.
This
current
is
controlled
by
the
026
emitter
resistor
which
is
selected
by
the
COINCIDENCE
REQUIREMENTS
switch.
The
voltage
pulse
produced
when
CR29
is
set
to
its
high
state
turns
027
and
029
off.
The
period
of
time
that
029
stays
off
is
equal
to
the
output
pulse
width
and
is
controlled
by
C9
and
R74.
If
a
different
output
pulse
width
is
desired,
the
value
of
C9
should
be
changed.
The
pulse
at
the
collector
of
029
is
de
coupled
to
the
output
connectors
through
two
emitter
followers
(O30
and
031).
In
the
quiescent
condition,
the
bases
of
these
transistors
are
at
zero
volts,
and
they
do
not
conduct.
The
amplitude
of
the
output
pulses
is
determined
by
the
ratio
of
R72
and
R75.
R75
should
be
increased
in
value
to
increase
the
output
pulse
amplitude.
An
output
pulse
amplitude
of
approximately
10
V
can
be
obtained
by
removing
R75
from
the
circuit.
6.
CALIBRATION
AND
MAINTENANCE
6.1.
TESTING
PERFORMANCE
OF
SLOW
COINCIDENCE
INTRODUCTION
The
following
paragraphs
are
int
ended
as
aids
in
the
installation
and
checkout
of
the
418A.
These
instructions
present
information
on
front-panel
controls
and
waveforms
at
test
points
and
output
connectors.
TEST
EQUIPMENT
The
following
or
equivalent
test
equipment
is
needed:
ORTEC
419
or
480
Pulse
Generator
ORTEC
410,
435A,
440A,
450,
or
451
Amplifier
Two
ORTEC
416
Gate
and
Delay
Generators
Tektronix
Model
580
Oscilloscope
lOOQ
BNC
terminators
PRELIMINARY
PROCEDURES
1.
Visually
check
module
for
possible
damage
due
to
shipment.
2.
Connect
ac
power
to
nuclear
standard
bin,
ORTEC
4001A/4002A.
3.
Plug
module
into
bin
and
check
for
proper
mechanical
alignment.
4.
Switch
on
ac
power
and
check
the
dc
power
supply
voltage
at
the
test
points
on
the
4001A
Power
Supply
control
panel.
COINCIDENCE
TESTING
1.
Connect
the
above
test
equipment
as
shown
in
Fig.
6.1.
The
ORTEC
416's
will
be
referred
to
as
416A
and
416B
for
clarity.
2.
Adjust
the
419
and
410
for
a
6-V
output
pulse
from
the
410.
3.
Set
the
416A
and
416B
controls
as
follows:
DELAY
RANGE
switch
^
^
DEI_AY
control
500
WIDTH
control
Minimum
AMPLITUDE
control
4
V
o*»Tec
onrEC
419
AMPUFtH
488
onrec
41M
OnTEC
lUt
POS
onrec
411
ABC
I.
I)
O
CH.
I
CM.
2
Fig.
6.1.
ORTEC
418A
Test
Circuit
4.
Set
the
418A
controls
as
follows:
INPUT
A
RESOLVING
TIME
Control
Maximum
COINCIDENCE
REQUIREMENTS
Control
2
INPUT
Controls
A
COIN
B
COIN
C
OFF
D
OFF
E
OFF
5.
Monitor
the
416A
and
416B
outputs
with
the
oscilloscope.
Adjust
the
416B
DELAY
control
until
the
leading
edges
of
the
two
pulses
are
in
coincidence.
6.
Monitor
the
416B
and
418A
outputs
with
the
oscilloscope.
An
output
pulse
should
be
present
at
the
418A
test
point.
Increase
the
416B
DELAY
control
until
the
418A
output
pulse
disappears.
7.
Check
the
416A
and
416B
outputs
with
the
oscilloscope
again.
The
leading
edges
of
these
two
pulses
should
be
2
jJs
apart.
8.
Repeat
steps
4
through
7
except
for
the
following
changes;
Set
INPUT
A
RESOLVING
TIME
Control
to
Minimum.
Step
7
The
leading
edges
of
the
two
pulses
from
the
416A
and
416B
should
be
less
than
100
ns
apart.
9.
Place
41BA
input
control
switches
to
OFF,
INPUT
A
RESOLVING
TIME
to
0.1
jJs.
and
COINCIDENCE
REQUIREMENTS
to
1.
10.
Sequentially
place
each
INPUT-CONTROL
switch
to
COINCIDENCE
and
then
to
OFF.
An
output
pulse
should
appear
on
the
osc
illoscope
each
time
a
switch
is
placed
to
the
COINCIDENCE
position
and
should
disappear
when
the
switch
is
returned
to
OFF
position.
416B
DELAY
RANGE
DELAY
WIDTH
AMPLITUDE
41
BA
1.0-11
500
0.4
jJs
5
V
INPUT
A
RESOLVING
TIME
CONTROL
2
|Js
COINCIDENCE
REQUIREMENTS
1
INPUT
CONTROLS
A
and
D
OFF
B,
C,
and
E
COINCIDENCE
11.
Place
the
COINCIDENCE
REQUIREMENTS
switch
to
2.
Place
switch
A
to
the
COINCIDENCE
position
and
all
others
to
the
OFF
position.
An
output
pulse
should
not
be
present.
Place
switch
B
to
the
COINCIDENCE
position
and
an
output
pulse
should
appear.
12.
Place
the
COINCIDENCE
REQUIREMENTS
switch
to
3
and
the
output
pulse
should
disappear.
Place
switch
C
to
the
COINCIDENCE
position
and
an
output
pulse
should
appear.
13.
Place
the
COINCIDENCE
REQUIREMENTS
switch
to
4
and
the
output
pulse
should
disappear.
Place
switch
D
to
the
COINCIDENCE
position
and
an
output
pulse
should
appear.
14.
Place
the
COINCIDENCE
REQUIREMENTS
switch
to
5
and
the
output
pulse
should
disappear.
Place
switch
E
to
the
COINCIDENCE
position
and
an
output
pulse
should
appear.
15.
Reduce
the
416A
and
416B
output
pulses
to
2.0
V
and
ensure
that
a
pulse
st
ill
appears
at
the
41
BA
output.
Reset
the
416A
and
416B
output
pulses
to
5V.
16.
Load
both
41
BA
outputs
with
100
Q.
The
41
BA
output
pulses
should
be
a
minimum
of
5
V
in
amplitude
and
500
ns
wide.
17.
Set
instrument
controls
as
follows:
416A
IB.
Monitor
the
41
BA
output
with
the
osc
illoscope.
An
output
pulse
should
be
present.
Sequentially
place
switches
A
and
D
to
the
ANTICOINCIDENCE
mode
and
ensure
that
the
output
pulse
disappears.
19.
Change
the
instrument
controls
as
follows:
416A
DELAY
WIDTH
416B
DELAY
WIDTH
41
BA
500
0.4,
|Js
400
4
|Js
INPUT
A
RESOLVING
TIME
Control
0.1
ps
INPUT
CONTROLS
A
and
D
COINCIDENCE
B.
C,
and
E
OFF
20.
Monitor
the
41
BA
Output
with
the
osc
illoscope.
Ensure
that
the
41
BA
output
pulse
disappears
as
switches
B,
C,
and
E
are
sequentially
switched
to
the
ANTICOINCIDENCE
position.
DELAY
RANGE
1.0-11
DELAY
400
WIDTH
4
jJs
AMPLITUDE
5
V
6.2.
SUGGESTIONS
FOR
TROUBLESHOOTING
Recheck
front-panel
control
settings.
Ensure
that
the
number
of
INPUT
CONTROL
switches
in
the
COINCIDENCE
position
is
equal
to
or
exceeds
the
number
selected
by
the
COINCIDENCE
REQUIREMENTS
switch.
If
the
418A
is
still
suspected
of
malfunctioning,
it
is
essential
to
verify
such
malfunctioning
in
terms
of
simple
pulse
generator
impulse
at
the
input
and
output.
In
consideration
of
this,
the
418A
must
be
disconnected
from
its
position
in
the
system,
and
routine
diagnostic
analysis
performed
with
a
test
pulse
generator
and
osc
illoscope.
It
is
imperative
that
testing
not
be
performed
with
a
source
and
detector
until
the
logic
inputs
to
the
coincidence
unit
perform
satisfactorily
with
the
test
pulse
generator.
The
testing
instructions
in
Section
6.1
Of
this
manual
and
the
circuit
description
in
Section
5
should
provide
assistance
in
locating
the
region
of
trouble
and
remedying
the
malfunctioning.
The
guide
plate
and
shield
cover
can
be
completely
removed
from
the
module
to
enable
osc
illoscope
and
voltmeter
observations
with
a
minimal
chance
of
accidentally
short-circuiting
portions
of
etched
board.
The
418A
may
be
returned
to
ORTEC
for
repair
service
at
nominal
cost.
Our
standardized
procedure
requires
that
each
repaired
instrument
receive
the
same
extensive
quality
control
tests
that
a
new
instrument
receives.
6.3.
TABULATED
TEST
POINT
VOLTAGES
ON
ETCHED
BOARD
The
following
dc
voltages
are
intended
to
indicate
the
typical
voltages
measured
on
the
etched
circuit
board.
The
voltages
given
here
should
not
be
considered
as
absolute
values,
but
should
be
used
as
an
aid
in
troubleshooting.
All
voltages
were
measured
from
ground
with
a
DVM
having
an
input
impedance
of
10
MQ
or
greater.
Voltages
are
dc
values
with
no
input
pulses.
Set
INPUT
A
RESOLVING
TIME
Control
to
0.1
ps
(min).
Set
COINCIDENCE
REQUIREMENTS
switch
to
1.
Test
Point
Voltaae
Test
Point
Voltaqe
QIC
11.5
Q18b
1.8
Q4b
14.5
018c
10.8
Q6b
0.7
021
b
0
Q6c
10.0
Q22b
1.8
Q7c
11.9
Q22c
10.8
Q9b
0
Q25b
-0.6
QlOb
1.8
Q26b
-2.9
01
Oc
10.8
Q26c
0
Q13b
0
Q27b
-12.0
Q14b
1.8
Q29b
-11.7
Q14c
10.8
Q29c
-
0.3
Q17b
0
BIN/MODULE
CONNECTOR
PIN
ASSIGNMENTS
FOR
STANDARD
NUCLEAR
INSTRUMENT
MODULES
PER
DOE/ER^MSTT
F^n
Function
F5n
Function
1
+3
volts
23
Reserved
2
-3
volts
24
Reserved
3
Spare
Bus
25
Reserved
4
Reserved
Bus
26
Spare
5
Coaxial
27
Spare
6
Coaxial
*28
+
24
volts
7
Coaxial
*29
-24
volts
8
200
volts
dc
30
Spare
Bus
9
Spare
31
Spare
*10
+6
volts
32
Spare
*11
-6
volts
*33
117
volts
ac
(Hot)
12
Reserved
Bus
*34
Power
Return
Ground
13
Spare
35
Reset
(Sealer)
14
Spare
36
Gate
15
Reserved
37
Reset
(Auxiliary)
*16
+12
volts
38
Coaxial
*17
-12
volts
39
Coaxial
18
Spare
Bus
40
Coaxial
19
Reserved
Bus
*41
117
volts
ac
(Neut.)
20
Spare
*42
High
Quality
Ground
21
Spare
G
Ground
Guide
Pin
22
Reserved
Pins
marked
(*)
are
installed
and
wired
in
ORTEC
4001A
and
4001C
Moduiar
System
Bins.
laani'iM
s
RiSOU/HH
7IM£
COh/STANT
CURR£HT
CenZRKTOR
a4
*14
V.
MAX£S
■r
IhlDSAtUDSRT
OR
Ih/RUT
PULiS.
V^IOTM
PROMT
PAPCL
INPUT
CURRENT
SWITCH
i
CURRENT
DRIVER
06.
as
CURRENT
switch
4
OR!
VCR
a/-«3
INPUT
SHOT
tIMITER
027-029
01,
oz
ANT
aC.SCHMITT
TRICOCRt
CURRENT
DRIVER
a9-Ql2
INPUT
IIWIITER
D6,D7
R/9-R2/
CURRSNT
SOURCE
a26
ANTI
COINCIDENCE.
a2&
ANT!
o.cscNMrrr
TRICC,CR4
CURRENT
DRIVER
INPUT
COIN
coincidence
REQUIREMENTS
SWITCN,
IIMITER
OIZ,
DI3
R30-R32
013-016
-2*V.
T
COINCIDENCE
'
LINE
D.CSCNMITT
TRIGGER
*
INPUT
com
L/MITER
on
,Di
a
R'70-RAZ
CURRENT
driver
ANTI-COINCIDENCE
LINE.
luNTI
0.17-a
20
UNUSS
OTHERWISE
SrECIflEO
OlMINilONS
IN
MCHIt
OAK
RIOOE
TECHNICAL
ENTERPRISES
CORPORATION
OAK
llOOl
TINNlSStf
lOlllANCiS
DESCMMITT
trigger
*
CURRENT
DRIVER
021-024
INPUT
COIN
IIMITER
022.
02S
RSO'Ral
IIACIION
MODEL
^/8A
UNIVEEeAL
CD>t^aDEH(LE
BU3C,^<
OlAliiMAH
SaTi
P.'fsiV.
(bM\-70
nVj
INO.
MILAVA
SUtMCf
MNtSH
A#ruio
HAcrtcu
0.
AHlOVAt
MAWtNO
MO
4^8A-0\0\"51
FCRRITE
BEAD
•-t
'®-5
—
H
/
H-
—4
^/9
K
^
—EZS)—
—539—
^«30
4—
—iA-*0
—IRfTTI—
—
-G333^
I
-C3Z>
Y
-H13-
ji©
©
-C27zZ>
@
®
—tg^oi—
-KSD—
_(5a>-
^
©
©
-R53T—
@
-|g2*H-
-i»3st-67?>
_g2f)_
-223-
-K35SH
-dSJ-
-eH>
-CSZZD-
—W9^l—
—
'
-eaiH
-ms-
^
wn
-^35a—rea-
2523-
—I»J3>-
—SH}-
(Q^
—4
>7-»7
H-
—fsot-
^
-(sm-
—23J—
—S3e^-
—(jyg^
c-\-tsja-
-cnnH
—Cm3>
•♦dnD—
•4<3L&—
♦C/2
C/3
+•
-g^}—
-em-
0
0
—S3-
0
T
@
J
"•**
w«T
»«l»
MM
4^dfS-02C7l
(o)
C7VV&
WAS
4l&Ar-0200
"*4^
3""
1
►
|:
i
f
?
M
-i<
:i
s
iJ
Q
040
■
a
UMCss
ometwisf
>/»
2121.
C
ORTEC
OM
BDC<
TiOMCM
rn
mss
cowounoM
MOOCV-
A4&A
P^^;B
ASSY,
C04MC40€»CE.
<3-4<-TO
4G48aO
Table of contents
Other ORTEC Measuring Instrument manuals
ORTEC
ORTEC 276 Service manual
ORTEC
ORTEC EASY-MCA-8K User manual
ORTEC
ORTEC DSPEC User manual
ORTEC
ORTEC Detective-EX-100T User manual
ORTEC
ORTEC DSPEC Pro Instructions for use
ORTEC
ORTEC 935 Service manual
ORTEC
ORTEC 455 User manual
ORTEC
ORTEC 550A Service manual
ORTEC
ORTEC 420 User manual
ORTEC
ORTEC 551 Service manual
