Eg&g Ortec 552 Service manual

n

Model

552

Pulse-Shape

Analyzer

and

Timing

Single-Channel

Analyzer

Operating

and

Service

Manual

Model

552

Pulse-Shape

Analyzer

and

Timing

Single-Channel

Analyzer

Operating

and

Service

Manual

This

manual

applies

to

instruments

marked

"Rev

27"

on

rear

panel

2845

0.5C

0485

standard

Warranty

for

EG&G

ORTEC

Nuclear

Electronic

Instruments

EG&G

ORTEC

warrants

that

the

items

will

be

delivered

free

from

defects

in

material

or

workmanship.

EG&G

ORTEC

makes

no

other

warranties,

express

or

implied,

and

specifically

NO

WARRANTY

OF

MERCHANTABILITY

OR

FITNESS

FOR

A

PARTICULAR

PURPOSE.

EG&G

ORTEC's

exclusive

liability

is

limited

to

repairing

or

replacing

at

EG&G

ORTEC's

option,

items

found

by

EG&G

ORTEC

to

be

defective

in

workmanship

or

materials

within

two

years

from

the

date

of

delivery.

EG&G

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

agree

ment

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

EG&G

ORTEC

fails

to

manufacture

or

deliver

items

called

for

in

this

agreement

or

pur

chase

order,

EG&G

ORTEC's

exclusive

liability

and

buyer's

exclusive

remedy

shall

be

release

of

the

buyer

from

the

obliga

tion

to

pay

the

purchase

price.

In

no

event

shall

EG&G

ORTEC

be

liable

for

special

or

consequential

damages.

Quality

Control

Before

being

approved

for

shipment,

each

EG&G

ORTEC

nuclear

electronic

instrument

must

pass

a

stringent

set

of

quality

controt

tests

designed

to

expose

any

flaws

in

materials

or

workmanship.

Permanent

records

of

these

tests

are

maintained

for

use

in

warrany

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,

EG&G

ORTEC

must

be

informed,

either

in

writing,

by

telephone

[(615)

482-4411]

or

by

telex

(55-7450)

of

the

nature

of

the

fault

of

the

instrument

being

re

turned

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

EG&G

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

nearest

EG&G

ORTEC

repair

center.

(In

the

case

where

the

instrument

did

not

function

upon

pur

chase,

EG&G

ORTEC

will

pay

shipment

costs

both

ways.)

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

will

be

repaired

at

the

standard

charge

unless

they

have

been

grossly

misused

or

mishandled,

in

which

case

the

user

will

be

notified

prior

to

the

repair

being

done.

A

quotation

will

be

sent

with

the

notification.

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

EG&G

ORTEC

of

the

circumstances

so

that

assistance

can

be

provided

in

making

damage

claims

and

in

providing

replacement

equipment

if

necessary.

Ill

CONTENTS

Page

WARRANTY

|j

PHOTOGRAPHS

jv

1.

DESCRIPTION

1

1.1.

Purpose

.|

1.2.

Lower-Level

Reference

''

"

|

2

1.3.

Output

Strobe

!!

!

'

!

2

1.4.

Constant-Fraction

Technique

2

2.

SPECIFICATIONS

2

2.1.

Performance

2

2.2.

Controls

!!!! !

2

2.3.

Inputs

. . .

3

2.4.

Outputs

3

2.5.

!

'

!

3

2.6.

Electrical

and

Mechanical

!

!!

"

'

!

3

3.

INSTALLATION

3

3.1.

General

3

3.2.

Connection

to

Power

3

3.3.

Connection

from

Linear

Amplifier

3

3.4.

Output

Connections

^

4

3.5.

Lower-Level

Reference

Input

4

4.

OPERATING

INSTRUCTIONS

4

5.

CIRCUIT

DESCRIPTION

5

5.1.

General

^

.

5

5.2.

Integrated

Circuits

!

^

!

6

5.3.

Lower-Level

Bias

6

5.4.

Upper-Level

Bias

7

5.5.

Input

Circuit

!

'

.

! !

7

5.6.

Lower-Level

Discriminator

''

7

5.7.

Upper-Level

Discriminator

^

7

5.8.

Channel

A

Discriminator

'

^

7

5.9.

Channel

B

Discriminator

! !!

!

8

5.10.

Reset

Circuit

^

g

5.11.

DC

Power

g

6.

MAINTENANCE

AND

CALIBRATION

9

6.1.

General

!

^

9

6.2.

Stretcher

Calibration

9

6.3.

Walk

Calibration

!

.

'

!!

9

6.4.

Lower-Level

Calibration

9

6.5.

Factory

Repair

'

g

Schematic

552-0201-S1

ILLUSTRATIONS

Fig.

1.1.

Typical

Walk

vs

Dynamic

Range

.|

Fig.

4.1.

Timing

Relationships

for

Input

and

Output

Pulses

for

Operation

with

Internal

Strobe

5

Fig.

5.1.

Simplified

Block

Diagram

of

the

552

PSA/T-SCA

'

^

6

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ORTEC

552

PULSE-SHAPE

ANALYZER

AND

TIMING

SINGLE-CHANNEL

ANALYZER

DESCRIPTION

1.1.

PURPOSE

The

ORTEC

552

PSA/T-SCA

provides

a

versatile

group

of

signal

derivation

functions.

It

can

be

used

as

either

a

single-channel

analyzer

or

as

an

integral

discriminator;

by

comparing

the

time

relationships

between

its

two

sets

of

outputs,

information

can

be

interpreted

for

pulse-

shape

analysis.

Each

input

signal

that

is

accepted

by

the

adjusted

amplitude

criteria

generates

two

separate

outputs,

each

precisely

time-related

to

the

input

signal.

For

reference

in

the

instrument,

one

output

signal

is

generated

through

channel

A

and

the

other

through

channel

B.

The

input

logic

circuits

can

be

used

in

any

of

three

modes,

selected

by

a

front

panel

switch.

The

Integral

mode

uses

the

adjusted

lower-level

discriminator

as

the

only

logic

reference

and

generates

an

output

if

the

input

signal

amplitude

exceeds

the

lower

level.

The

Normal

mode

uses

both

lower-level

and

upper-level

discriminators

and

generates

an

output

if

the

input

amplitude

exceeds

the

lower-level

bias

but

does

not

exceed

the

upper

level;

the

front

panel

Upper-Level

control

is

adjusted

within

a

range

of

0

to

10

V

with

ground

as

the

zero

reference

point.

The

Window

mode

operates

the

same

as

the

Normal

mode

except

that

the

zero

reference

point

for

the

Upper-Level

control

is

equal

to

the

adjusted

lower

level

and

the

range

of

the

Upper-Level

control

is

0

to

1

V.

The

lower

level

for

any

mode

can

be

furnished

from

the

front

panel

control

or

by

a

dc

input

signal

through

a

rear

panel

connector.

An

output

signal

through

channel

A

is

generated

by

the

constant-fraction

method

on

the

trailing

edge

of

the

input

signal,

after

the

logic

for

acceptance

has

been

completed.

The

fraction

is

selectable

at

10%,

20%,

or

50%

measured

down

from

the

peak

pulse

height,

using

a

jumper

on

the

printed

circuit

board

to

select

the

fraction.

The

output

occurs

promptly

at

the

constant-fraction

point

on

the

trailing

edge

and

is

a

NIM-standard

fast

negative

output

pulse

with

excellent

timing

characteristics.

An

output

signal

through

channel

B

is

also

generated

by

the

constant-fraction

method

on

the

trailing

edge

of

the

input

signal.

The

fraction

for

channel

B

is

selected

by

a

front

panel

switch

that

can

be

set

for

any

level

from

10%

through

100%

(bipolar

crossover)

in

10%

increments

of

the

peak

pulse

height.

The

unit

must

be

strobed,

either

internally

or

externally,

for

an

output

pulse

to

be

provided.

When

the

rear

panel

switch

selects

internal

strobe,

the

channel

B

outputs

are

generated

after

an

adjusted

delay

following

the

constant-fraction

trigger

point;

the

delay

is

adjusted

on

the

front

panel

within

the

range

of

0.1

to

1.1

/iS,

permitting

normalization

for

specific

applications.

When

the

rear

panel

switch

selects

external

strobe,

the

channel

B

outputs

are

generated

promptly

when

a

NIM-

standard

positive

strobe

is

furnished

through

the

rear

panel

connector:

the

strobe

signal

must

be

furnished

within

10

MS

after

the

channel

B

constant-fraction

trigger

point.

There

are

two

channel

B

outputs;

one

is

a

NIM-

standard

fast

negative

pulse

and

the

other

is

a

NIM-

standard

slow

positive

pulse.

By

using

an

internally-strobed

channel

B

output,

the

timing

differentials

between

channels

A

and

B

can

be

used

to

measure

the

decay

characteristics

of

an

input

pulse

as

the

constant-fraction

points

of

the

two

channels

are

changed.

For

example,

using

a

50%

fraction

for

channel

A

and

10%

for

channel

B,

the

time

difference

on

the

decaying

waveform

can

be

measured

by

sub

tracting

the

channel

B

delay.

In

many

applications,

the

decay

time

of

the

pulse

is

significant

for

the

type

of

par

ticle

that

is

detected

so

the

pulse

shape

can

be

used

to

identify

the

nature

of

the

source.

The

552

accepts

either

unipolar

or

bipolar

input

pulses

having

either

RC

or

delay-line

pulse-shaped

waveforms.

It

includes

an

input

attenuator

so

that

an

input

amplitude

can

be

reduced

by

a

factor

of

1,

10,

or

100,

selected

by

a

front

panel

toggle

switch.

The

walk

of

the

attenuator

is

typically

less

than

1

ns.

This

feature

can

be

used

to

optimize

the

timing

accuracy

of

both

output

channels.

The

walk

characteristics

can

be

optimized

individually

in

each

channel,

using

a

front

panel

screwdriver

adjust

ment

for

each

channel.

When

these

controls

are

adjusted

properly,

the

walk

characteristics

for

a

bipolar

delay-line

shaped

input

are

less

than

2.5

ns

over

a

200:1

dynamic

range

of

input

amplitudes

(see

Fig.

1.1).

The

instrument

is

designed

to

meet

the

interchangeability

standards

recommended

by

USAEC

Report

TID-28093

(Rev).

An

ORTEC

401/402

Series

Bin

and

Power

Supply

provides

all

the

necessary

power

through

the

rear

panel

module

connector.

All

signal

levels

and

impedances

are

compatible

with

other

ORTEC

NIM

modules.

5

1,0

!

1 1 1 1

552

f

=

0,5

Mi

l

460

Amp

Bipolar

Output

Tektronix

Attenuator

Channel

8

-

—

Channel

A

i

1

1 1 1

1

1 1

40:1

60.1

80:1

100:1

200:1

Dynamic

Range

Fig.

1.1.

Typical

Walk

vs

Dynamic

Range.

1.2.

LOWER-LEVEL

REFERENCE

A

rear

panel

toggle

switch

selects

either

the

front

panel

Lower-Level

control

or

the

voltage

signal

furnished

through

the

rear

panel

LL

Ref

connector

as

the

reference

for

the

lower-level

discriminator.

This

permits

flexibility

in

operation,

where

an

external

reference

source

can

furnish

the

lower-level

threshold

from

a

stepped-

or

sliding-voltage

source

to

automatically

sweep

the

SCA

response

through

a

spectral

range.

The

selected

source

for

the

lower-level

reference

is

effective

for

all

three

operating

modes.

1.3.

OUTPUT

STROBE

A

rear

panel

toggle

switch

selects

either

an

internal

strobe,

based

on

a

delayed

trigger

derived

from

the

input

signal,

or

a

strobe

pulse

that

is

furnished

through

the

rear

panel

Strobe

In

connector

to

determine

when

the

channel

B

outputs

are

to

be

generated.

This

has

no

effect

on

the

channel

A

output,

which

is

generated

promptly

at

the

constant-fraction

trigger.

When

external

strobe

is

used,

the

input

signal

must

be

received

within

10

yus

after

the

trigger

time

or

the

channel

B

outputs

will

not

be

generated.

When

the

internal

strobe

is

used,

the

Delay

control

on

the

front

panel

can

be

adjusted

to

set

the

de

lay

time

from

the

trigger

point

to

the

channel

B

output

in

the

range

of

0.1

through

1.1

^s.

1.4.

CONSTANT-FRACTION

TECHNIQUE

Both

output

channels

derive

information

that

uses

the

constant-fraction

technique,

which

is

an

ORTEC

devel

opment.

It

consists

of

comparing

the

amplitude

along

the

decay

of

a

pulse

to

a

selected

fraction

of

the

peak

amplitude

of

the

same

pulse.

Thus,

through

a

wide

range

of

input

pulse

peak

amplitudes,

the

timing

information

is

obtained

with

precision.

The

reference

fractions

that

are

available

in

both

output

channels

indicate

the

percentage

of

amplitude

decay

from

the

peak

toward

the

ground

reference

level.

Thus

a

setting

of

10%

in

either

channel

selects

a

trigger

point

at

90%

of

the

peak

amplitude

for

that

channel,

or

a

setting

of

20%

selects

a

trigger

point

at

80%

of

the

peak

ampli

tude.

2.

SPECIFICATIONS

2.1.

PERFORMANCE

INPUT

DYNAMIC

RANGE

200:1.

PULSE-PAIR

RESOLVING

TIME

Output

pulse

width

plus

Delay

(selected

by

front

panel

Delay

control

or

by

external

strobe

input)

plus

200

ns

for

NIM-standard

fast

negative

output

or

plus

740

ns

for

NIM-standard

slow

positive

output.

Minimum

resolving

time

for

negative

output,

260

ns;

for

positive

output,

800

ns.

THRESHOLD

TEMPERATURE

INSTABILITY

^0.005%/

°C

of

full

scale,

0

to

50°

0.

DISCRIMINATOR

NONLINEARITY

^±0.25%

of

full

scale

(Integral)

for

each

discriminator.

DELAY

TEMPERATURE

INSTABILITY

^±0.01

%/°C

of

full

scale,

0

to

50°C,

measured

at

full

scale.

DELAY

NONLINEARITY

^±2%

of

delay

range.

WINDOW

WIDTH

INCONSISTENCY

<±0.1%

variation

of

full-scale

window

width

over

the

0-to

10-V

linear

range.

MINIMUM

INPUT

THRESHOLD

40

mV,

TIME

SHIFT

vs

PULSE

HEIGHT

(Walk)

(Specified

for

Channels

A

and

B

at

50%

fraction.)

Walk

(ps)

Input

Oynamic

Range

System

1*

System

II**

10:1

±500

±2000

50:1

±1500 ±2500

100:1

±2000 ±3000

200:1

±2500 ±8000

*Uslng

the

bipolar

output

of

an

ORTEC

460

Amplifier,

single

delay-line

mode,

integrate

<0.1

with

delay

line

1

^s.

**Using

an

ORTEC

472A

Amplifier,

unipolar

output,

0.5

mS

shaping.

2.2.

CONTROLS

UPPER

LEVEL

Front

panel

10-turn

potentiometer

deter

mines

the

window

width

(0

to

+1

V)

in

the

Window

mode

or

the

Upper

Level

(0

to

+10

V)

in

the

Normal

and

Integral

modes

(not

used

to

determine

SCA

outputs

during

Inte

gral

mode

operation).

LOWER

LEVEL

Front

panel

10-turn

potentiometer

ad

justable

from

40

mV

to

10

V;

when

the

rear

panel

LL

Ref

switch

is

set

for

Int,

determines

the

threshold

setting

for

the

Lower-Level

discriminator;

when

the

LL

Ref

switch

is

set

at

Ext,

this

control

is

ineffective.

MODE

Front

panel

3-position

locking

toggle

switch

selects

one

of

three

operating

modes:

INT

(Integral)

LL

sets

a

single

discriminator

threshold

(40

mV

to

10

V)

and

UL

is

not

used

to

determine

an

SCA

response.

NORM

(Normal)

UL

and

LL

are

independently

adjust

able

levels;

UL

range

0

to

+10

V;

LL

range

40

mV

to

10

V.

WIN

(Window)

LL

sets

the

baseline

level

(40

mV

to

10

V)

and

UL

sets

the

window

width

(LL

to

LL+1

V).

ATTN

Front

panel

3-position

locking

toggle

switch

selects

an

attenuation

factor

for

the

input

signals:

XI

Input

signals

not

attenuated.

X10

Input

signals

are

attenuated

by

a

factor

of

1/10.

X100

Input

signals

are

attenuated

by

a

factor

of

1/100.

DELAY

Front

panel

10-turn

potentiometer

for

continu

ously

adjustable

delay

for

channel

B

output,

using

inter

nal

strobe;

range

0.1

to

1.1

ms.

WALK

ADJ

(A

and

B)

Independent

front

panel

screw

driver

adjustments

on

front

panel

for

precise

setting

of

walk

compensation

in

each

output

channel.

The

Walk

Adj

B

control

is

ineffective

when

the

B

Fraction

switch

is

set

at

its

Bl

position.

LL

REF

MODE

Rear

panel

2-position

locking

toggle

switch

selects

either

the

front

panel

LL

control

or

the

voltage

signal

applied

to

the

rear

panel

LL

Ref

Ext

con

nector

for

the

lower-level

discriminator

reference

thresh

old.

STROBE

MODE

Rear

panel

2-position

locking

toggle

switch

selects

either

an

internal

strobe,

derived

from

the

input

signal,

or

an

external

strobe,

furnished

through

the

adjacent

connector,

to

generate

a

channel

B

output.

The

automatic

reset

time

is

»10

/jls.

B-FRACTION

Front

panel

switch

selects

the

constant

fraction

that

will

be

used

for

the

channel

B

response

point:

marked

.1

through

.9

and

Bl

for

10%

through

90%

and

bipolar

crossover

(100%),

referring

to

the

decay

after

the

peak

of

the

input

waveform.

A-FRACTION

An

internal

jumper

selects

the

constant

fraction

that

will

be

used

for

the

channel

A

response

point;

jumper

positions

are

10%,

20%,

and

50%,

referring

to

the

decay

from

the

peak

of

the

input

waveform.

2.3.

INPUTS

INPUT

Front

panel

dc-coupied

BNC

connector

accepts

positive

unipolar

or

bipolar

signals,

0

to

+10

V

linear

range,

±12

V

maximum;

width,

^100

ns;

lOOOfl

input

im

pedance.

LL

REF

IN

Rear

panel

BNC

accepts

lower-level

bias

when

the

LL

Ref

mode

switch

selects

Ext.

An

input

of

0

to

-10

V

on

this

connector corresponds

to

a

range

of

0

to

+10

V

for

the

front

panel

Lower-Level

control.

Input

pro

tected

to

±24

V.

EXT

STROBE

IN

Rear

panel

BNC

accepts

a

NIM-stand-

ard

slow

positive

pulse,

nominally

+5

V,

500

ns

wide,

to

cause

an

output

to

occur

from

the

channel

B

circuits

when

the

Strobe

switch

is

set

at

Ext.

The

external

strobe

must

be

provided

within

10

/is

after

the

linear

input.

At

the

end

of

this

period,

the

552

resets

its

internal

logic

without

producing

a

channel

B

output.

2.4.

OUTPUTS

SCA

NEG

OUT

A

Front

panel

BNC

connector

provides

NIM-standard

fast

negative

output

pulses

from

channel

A

only;

nominally

-16

mA

(-800

mV

on

50n

load),

^20

ns

wide,

^5

ns

rise

time.

Output

occurs

promptly

at

the

channel

A

constant

fraction

trigger

point.

SCA

NEG

OUT

B

Front

panel

BNC

connector

provides

NIM-standard

fast

negative

output

pulses

from

channel

B

only;

nominally

-16

mA

(-800

mV

on

50n

load),

^20

ns

wide,

^5

ns

rise

time.

Output

occurs

promptly

at

strobe

time.

SCA

POS

OUT

B

Front

and

rear

panel

BNC

connectors

provide

NIM-standard

slow

positive

output

pulses

from

channel

B

only;

nominally

+5

V,

500

ns

wide,

^20

ns

rise

time.

Output

occurs

promptly

at

strobe

time.

Zo

^lOn.

LL

OUT

Rear

panel

BNC

connector

provides

positive

NIM-standard

output,

nominally

+5

V,

500

ns

wide.

Out

put

occurs

as

leading

edge

of

the

linear

input

crosses

the

LL

threshold,

Zo

^lOfl.

UL

OUT

Rear

panel

BNC

connector

provides

positive

NIM-standard

output,

nominally

+5

V,

500

ns

wide.

Out

put

occurs

as

leading

edge

of

the

linear

input

crosses

the

UL

threshold.

Zo

<10n.

2.5.

The

552

is

compatible

with

all

ORTEC

amplifiers

and

other

amplifiers

having

a

0-

to

+10-V

linear

output

range.

2.6.

ELECTRICAL

AND

MECHANICAL

POWER

REQUIRED

+24

V,

83

mA;

-24

V,

83

mA;

+12

V,

166

mA;

-12

V,

166

mA.

DIMENSIONS

NIM-standard

single-width

module

(1.35

by

8.714

inches)

per

TID-20893

(Rev).

3.

INSTALLATION

3.1.

GENERAL

The

552

must

be

used

in

conjunction

with

an

ORTEC

401/

402

Series

Bin

and

Power

Supply,

or

equivalent,

which

is

intended

for

rack

mounting.

If

any

source

of

heat

is

oper

ating

in

the

same

rack,

there

must

be

sufficient

cooling

air

circulating

to

prevent

any

localized

heating

of

the

transis

torized

and

integrated

circuits

used

throughout

the

552.

The

temperature

of

equipment

mounted

in

racks

can

easily

exceed

the

maximum

unless

precautions

are

taken;

the

552

should

not

be

subjected

to

temperatures

in

excess

of

120°F

(50°

C).

3.2.

CONNECTION

TO

POWER

Turn

off

the

Bin

Power

Supply

when

inserting

or

removing

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

con

tains

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

the

do

voltage

levels.

When

using

the

552

outside

the

401/402

Bin

and

Power

Supply,

be

sure

that

the

power

extension

cord

or

cable

that

is

used

properly

accounts

for

the

power

supply

grounding

circuits

that

are

provided

according

to

the

recommended

AEC

standards

outlined

in

TID-20893

(Rev).

Both

high-quality

and

power-return

ground

con

nections

are

provided

to

ensure

proper

reference

voltage

feedback

into

the

power

supply,

and

these

must

be

pre

served

in

remote

cable

installations.

Be

careful

also

to

avoid

ground

loops

when

the

module

is

operated

outside

the

bin.

3.3.

CONNECTION

FROM

LINEAR

AMPLIFIER

The

Input

BNC

connector

on

the

front

panel

accepts

posi

tive

unipolar

or

bipolar

signals

through

a

dc-coupied

input

path.

For

bipolar

input

pulses,

the

positive

lobe

will

be

analyzed.

The

amplifier

output

should

be

adjusted

so

that

there

is

no

dc

offset,

and

the

poie-zero

networks

are

adjusted

properly.

The

input

Impedance

of

the

552

is

lOOOfi.

When

long

cables

are

used

to

connect

the

amplifier

output

to

the

552

Input,

cable

termination

may

be

necessary

in

orderto

pre

vent

reflections:

match

the

cable

impedance

with

a

term

inator

at

the

552

Input

in

such

cases.

Normally,

the

ATTN

switch

on

the

552

front

panel

will

be

left

at

its

XI

setting

for

operation

in

a

system.

The

main

purpose

for

the

X10

and

X100

attenuator

settings

are

to

aid

in

precise

walk

adjustments.

3.4.

OUTPUT

CONNECTIONS

Outputs

are

furnished

through

both

channel

A

and

channel

B

connectors.

Each

channel

is

considered

sepa

rately

because

of

the

differences

in

timing

characteristics

of

the

two

channels.

The

channel

A

output

on

the

front

panel

is

dependent

only

on

satisfaction

of

the

input

logic

of

the

single-channel

analyzer

and

it

occurs

at

the

se

lected

trigger

level

on

the

trailing

edge

of

the

linear

input.

The

channel

B

outputs

are

dependent

on

satisfaction

of

input

logic

and

of

a

strobe,

which

can

be

either

internally

generated

or

furnished

from

an

external

source.

The

channel

A

output

is

available

as

a

NIM-standard

fast

negative

pulse

from

a

front

panel

BNC

connector.

It

is

intended

for

transmission

to

the

driven

unit

through

50n

cable

with

50fl

termination.

When

the

552

is

set

for

either

the

Normal

or

Window

mode,

a

channei

A

output

means

that

an

input

pulse

amplitude

is

sufficient

to

trigger

the

lower-level

discriminator

without

also

triggering

the

upper-levei

discriminator.

When

the

552

is

set

for

the

Integral

mode

of

operation,

the

channel

A

output

means

that

the

input

pulse

amplitude

is

sufficient

to

trigger

the

lower-level

discriminator;

triggering

of

the

upper-level

discriminator

does

not

affect

the

output

for

this

mode.

The

time

when

a

channel

A

output

is

made

available

is

promptly

at

a

trigger

point

on

the

decay

of

the

input

wave

form.

The

decay

level

is

selected

by

an

internal

jumper

on

the

printed

circuit

board,

which

can

be

set

for

10%,

20%,

or

50%,

referring

to

the

decay

from

the

peak

amplitude

of

the

pulse.

Three

channel

B

outputs

are

available.

A

NIM-standard

fast

negative

pulse

is

furnished

through

a

front

panel

con

nector

and

a

NIM-standard

slow

positive

puise

is

fur

nished

through

both

front

and

rear

panel

connectors.

The

negative

output

is

intended

for

transmission

to

the

driven

unit

through

50n

cable

with

50fl

termination.

The

positive

outputs

can

be

furnished

through

50n

or

93n

cable

to

the

driven

unit.

A

channei

B

output

means

that

the

logic

for

the

channel

A

output

has

been

satisfied

and

that

an

output

strobe

is

furnished.

The

output

strobe

can

be

generated

internally

or

furnished

from

an

external

source,

depend

ing

on

the

setting

of

the

rear

panel

switch.

The

time

when

the

channel

B

outputs

are

generated,

using

the

internal

strobe,

is

at

a

fixed

delay

after

the

trig

ger

point

on

the

decay

of

the

input

waveform.

The

decay

level

is

selected

by

a

front

panel

switch

that

can

be

set

at

any

multiple

of

10%

from

10%

through

100%

(baseline

crossover

of

a

bipolar

input),

referring

to

the

decay

from

the

peak

amplitude

of

the

pulse.

The

range

of

the

front

panel

Delay

control

is

about

0.1

through

1.1

fiS.

The

channel

B

output

time,

using

an

external

strobe,

is

promptly

at

the

strobe

pulse;

this

strobe

pulse

must

be

furnished

within

10

ns

after

the

trigger

point

or

the

in

ternal

logic

is

reset

without

generating

a

channel

B

out

put.

Separate

logic

outputs

are

available

through

the

rear

panel

to

indicate

when,

on

the

leading

edge

of

an

input

pulse,

each

of

the

two

discriminators

is

triggered.

These

responses

can

be

used

to

monitor

the

discriminator

levels

during

adjustment,

to

be

counted

in

external

sealers,

to

provide

subgroup

routing

to

a

multichannei

analyzer,

or

for

any

other

applications

desired.

Each

logic

output

for

LL

Out

and

UL

Out

is

a

NIM-standard

slow

positive

pulse

that

is

compatible

with

ORTEC

counters,

ratemeters,

and

other

Instruments.

The

output

impedance

through

each

output

path

is

sufficiently

low

to

drive

as

many

as

ten

paralleled

lOOOfl

inputs.

3.5.

LOWER-LEVEL

REFERENCE

INPUT

If

the

LL

Ref

toggle

switch

on

the

rear

panel

of

the

552

is

set

at

Ext,

the

reference

level

for

the

lower-level

discrim

inator

must

be

furnished

through

the

adjacent

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.

The

signal

through

the

LL

Ref

In

connector

is

not

used

unless

the

toggle

switch

is

set

at

Ext.

4.

OPERATING

INSTRUCTIONS

After

the

552

has

been

connected

into

a

system

according

to

the

installation

information

in

Section

3,

the

operating

and

strobe

modes

can

be

selected

and

the

discriminator

thresholds

can

be

adjusted

as

required

for

each

appli

cation.

Figure

4.1

illustrates

the

timing

relationships

that

will

be

effective

in

the

552,

operating

with

an

internal

strobe,

for

each

of

three

possible

input

pulse

ampitudes.

The

first

two

pulses

exceed

the

lower-level

threshold

without

also

exceeding

the

upper

level,

and

the

third

pulse

exceeds

both

threshold

levels.

Superimposed

on

each

of

these

input

pulses

in

Fig.

4.1

are

two

internally

stretched

con

stant-fraction

reference

levels;

the

upper

stretched

level

is

at

the

50%

point

on

the

input

pulse

decay,

which

can

be

set

in

channel

A;

the

lower

stretched

level

is

at

the

70%

point

on

the

input

pulse

decay,

which

can

be

set

in

channel

B.

When

the

input

pulse

decays

through

the

50%

level,

the

channel

A

CF

discriminator

is

fired

and

triggers

a

prompt

channel

A

output.

When

the

input

pulse

decays

through

the

70%

level,

the

channel

B

CF

discriminator

is

fired

and

triggers

an

internal

delay,

which

then

generates

both

negative

and

positive

channel

B

outputs

at

the

end

of

the

delay.

The

delay

is

fron^anel

adjusted

in

the

range

of

0.1

through

1.1

ixs.

If

the

552

is

set

for

Normal

or

Window

mode,

time-significant

pulses

would

be

generated

for

A

Fraction

50%

,._ri

JT

Channel

B

Trigger

"T"

"T

Delay

-

Channel

B

Neg

Out

Channel

8

Pos

Out,

y

J~L

1

y

jy

y,

n

I

/»

1/

I

Int

mode

only

Fig.

4.1.

Timing

Relationships

for

Input

and

Output

Pulses

for

Operation

with

Internal

Strobe.

each

of

the

first

two

input

pulses

but

none

would

be

gen

erated

for

the

third

pulse

because

it

is

too

large

to

satisfy

the

single-channel

criteria.

If

the

552

is

set

for

Integral

mode,

the

responses

would

be

generated

for

the

third

input

pulse,

as

shown

by

the

broken

line

output

pulses.

For

any

mode

of

operation,

the

LL

Out

and

UL

Out

pulses

are

generated

when

the

input

pulse

amplitude

exceeds

the

level.

The

adjusted

lower-level

threshold

is

furnished

from

either

the

front

panel

Lower-Level

control

or

an

external

source

that

is

furnished

through

the

rear

panel

LL

Ref

connector;

selection

of

the

source

is

made

with

the

rear

panel

LL

Ref

toggle

switch.

In

either

case,

the

range

(for

an

unattenuated

input

signal)

is

from

Oto+IO

V,

measured

from

chassis

ground.

The

adjusted

upper-level

threshold

is

determined

by

the

setting

of

the

front

panel

Upper-Level

control

and

by

the

mode

selector

toggle

switch.

When

the

switch

is

set

at

either

Int

or

Norm,

the

range

of

the

variable

control

is

from

0

to

+10

V,

measured

from

chassis

ground.

When

the

switch

is

set

at

Win,

the

range

of

the

variable

control

is

0

to

+1

V,

measured

above

the

adjusted

lower-level

threshold.

When

the

rear

panel

Strobe

switch

selects

Ext,

operation

of

the

552

is

the

same

as

it

is

for

Int

except

for

the

time

at

which

a

channel

B

output

is

made

available.

For

this

mode

of

operation,

an

external

strobe

pulse

must

be

furnished

after

the

channel

B

CF

trigger

time

and

before

an

auto

matic

reset,

and

the

channel

B

outputs

are

furnished

promptly

at

the

strobe

time.

The

time

window,

during

which

the

strobe

can

be

effective,

is

from

the

trigger

time

to

10

ms

after

the

trigger.

If

no

strobe

is

furnished

within

the

time

window,

the

internal

logic

is

reset

without

gen

erating

an

output

through

channel

B.

For

optimum

time-significant

outputs,

each

front

panel

Walk

Adj

control

must

be

trimmed

for

the

combined

effects

of

the

input

shaping

and

its

time

constants,

and

of

the

expected

dynamic

range

of

operation.

Using

a

dupli

cate

of

the

minimum

and

maximum

amplitudes

for

shaped

input

pulses,

set

each

control

to

provide

the

minimum

walk

for

its

respective

channel;

walk

is

the

variation

of

time

of

occurrence

vs

input

pulse

amplitude.

Using

internal

strobe,

the

decay

shape

of

an

input

pulse

can

be

reconstructed.

Use

the

following

steps.

1.

Select

the

same

fraction

for

both

channels

of

outputs,

and

adjust

the

Delay

control

as

desired.

2.

Connect

the

channel

A

output

to

the

Start

input

of

a

time-to-pulse-height

converter

(TPHC).

3.

Connect

the

channel

B

Neg

output

to

the

Stop

input

of

the

TPHC.

4.

Furnish

the

shaped

input

pulses

to

the

552

and

meas

ure

the

time

difference

between

the

channel

A

and

channel

B

outputs.

This

is

an

accurate

measurement

of

the

Delay

time

adjustment.

5.

Switch

the

B-Fraction

selector

to

each

of

its

active

settings,

10%

through

90%,

and

measure

the

time

differ

ences

at

each

level;

use

the

adjusted

Delay

time

to

correct

each

measurement.

Note;

Do

not

use

the

Bl

setting

of

the

B-Fraction

se

lector

unless

the

input

pulse

is

bipolar,

since

a

zero

crossover

is

necessary

to

obtain

a

channel

B

output

when

this

selection

has

been

made.

6.

Plot

the

decay

curve

for

the

input

pulses,

using

the

set

of

data

obtained

in

step

5.

CIRCUIT

DESCRIPTION

5.1.

GENERAL

Refer

to

block

diagram

552-0101-B1

and

schematic

dia

gram

552-0201-S1,

both

included

at

the

back

of

the

manual.

Figure

5.1

is

a

simplified

block

diagram

of

the

552

Pulse-

Shape

Analyzer

and

Timing

SCA.

It

shows

that

each

input

pulse

is

furnished

through

an

attenuator

(attenuation

factors

XI,

X10,

and

X100).

The

resulting

input

pulse

is

applied

to

each

of

four

discriminators

and

its

peak

is

also

stretched

and

attenuated

for

each

of

the

two

CF

(con

stant-fraction)

discriminators.

The

UL

(upper-level)

and

LL

(lower-level)

discriminators

form

the

single-channel

analyzer.

When

the

SCA

logic

is

satisfied,

it

gates

the

timing

outputs

of

the

two

channels

for

their

respective

outputs.

Each

of

the

four

discriminators

independently

triggers

a

response

when

the

amplitude

of

its

noninverted

input

exceeds

the

amplitude

of

its

inverted

input.

The

response

of

the

UL

and

LL

discriminators

is

latched

until

an

internal

reset

occurs.

The

stretcher

for

the

constant-

fraction

discriminators

is

also

reset

internally.

Reference

levels

for

the

UL

and

LL

discriminators

are

set

independently

for

either

Normal

or

Integral

mode

opera

tion.

For

Window

operation,

the

threshold

for

the

UL

dis

criminator

is

based

on

the

LL

setting

instead

of

ground.

Input

OUTPUT

GENERATOR

UL

DISC

Int

Norm/Win'

Int/Norm

A

Win

OUTPUT

GENERATOR

IL

DISC

ATTN

A

SCA

CURRENT

SWITCH

CHANNEL

A

GATE

CHANNE

CP

DISC

.2

A

Jumper

tor

Fraction

Select

CURRENT

SWITCH

CHANNEL

B

B-SCA

CHANNEL

DELAY

CP

DISC

PEAK

STRETCHER

Strobe

B-Praction

Switch

Strobe

OUTPUT

GENERATOR

@

UL

Out

LL

Out

A

Neg

Out

B

Neg

Out

-0(FP)

Fig.

5.1.

Simplified

Block

Diagram

of

the

552

PSA/T-SCA.

The

CF

discriminators

are

both

triggered

at

the

onset

of

each

input

pulse,

whether

its

amplitude

is

sufficient

to

trigger

either

of

the

other

two

discriminators

or

not.

Then

each

CF

discriminator

is

reset

when

the

input

pulse

decays

through

its

attenuated

peak-reference

level

be

cause

the

stretch

and

attenuate

circuit

has

generated

and

maintained

this

reference

level

by

that

time

and

has

fur

nished

it

as

the

reference

level

of

its

corresponding

discriminator.

The

stretched

input

to

the

attenuator

for

channel

A

can

be

used

to

set

the

reference

level

at

10%,

20%,

or

50%

of

the

decay

from

the

peak,

selected

by

a

jumper

location

on

the

printed

circuit

board,

J2.

The

same

stretched

input

is

supplied

to

the

channel

B

attenuator

which

can

select

a

reference

level

of

10%,

20%,

30%,

40%,

50%,

60%,

70%,

80%,

90%,

or

100%

of

the

decay

from

the

peak,

selected

by

a

front

panel

switch.

The

logic

gate

is

triggered

when

the

LL

discriminator

has

been

set

and

when

there

is

no

signal

from

the

UL

discrim

inator.

This

enables

a

gate

for

the

channel

A

discriminator

and

a

current

switch

generates

a

NIM-standard

fast

negative

output

promptly

at

the

discriminator

reset.

The

logic

gate

output

also

enables

a

gate

for

the

channel

8

discriminator

that

can

be

used

to

generate

channel

B

out

puts.

A

rear

panel

Strobe

switch

selects

either

an

internal

or

an

external

strobe

signal

for

the

delay

circuit.

If

the

external

strobe

.node

is

used,

the

circuits

are

reset

with

out

generating

a

channel

B

output

if

no

strobe

is

furnished

within

10

ns.

5.2.

INTEGRATED

CIRCUITS

The

nomenclature

used

to

identify

integrated

circuit

packages

in

this

manual

is

defined

below

for

the

example

IC1-7

where

and

10

=

integrated

circuit,

1

=

reference

designation,

7

=

number.

Any

portion

of

an

10

package

can

be

designated

by

its

output

number.

Thus

the

example

specifies

the

por

tion

of

101

that

includes

7

as

an

output.

5.3.

LOWER-LEVEL

BIAS

The

threshold

for

the

lower-level

discriminator

is

adjusted

with

the

front

panel

Lower-Level

control,

R53,

or

is

furnished

as

a

dc

level

through

0N2

on

the

rear

panel.

Switch

82

on

the

rear

panel

selects

which

source

is

effec

tive

for

the

lower-level

bias

reference.

For

the

internal

bias

circuit,

the

minimum

level

of

the

front

panel

control

is

normalized

with

potentiometer

R54,

mounted

on

the

printed

circuit.

The

actual

range

of

R53

Is

from

a

few

millivolts,

adjusted

by

R54,

to

-5

V.

The

ad

justed

level

is

buffered

through

IC1-1

and

inverted

without

being

amplified

through

IC1-7

to

be

furnished

as

the

reference

level

to

the

noninverting

input

of

discrim

inator

IC3.

For

the

external

bias

circuit,

a

dc

level

between

0

and

-10

V

can

be

furnished

through

CN2and

is

divided

by

R56

and

R57.

The

result

that

is

selected

by

switch

S2

is

then

furnished

through

the

same

buffering

and

coupling

net

work

to

the

lower-level

discriminator.

5.4.

UPPER-LEVEL

BIAS

The

threshold

for

the

upper-level

discriminator

is

ad

justed

with

the

front

panel

Upper-Level

control,

R48.

The

range

for

this

control

is

0

to

-5

V.

The

adjusted

level

is

buffered

through

IC1-14

and

furnished

through

either

R60

or

R61,

through

operational

amplifier

IC1-8,

and

to

the

noninverting

input

of

the

upper-level

discriminator,

IC2.

When

switch

S3

is

set

at

either

Integral

or

Normal,

the

gain

of

this

adjusted

bias

is

1.0;

when

the

switch

selects

Window,

the

gain

is

reduced

to

0.1

and

the

effec

tive

range

of

the

control

is

thus

reduced

by

a

factor

of

10.

Also,

when

the

switch

selects

Window,

the

level

that

is

furnished

from

IC1-1

for

the

lower-level

discriminator

is

also

furnished

through

R62

to

IC1-8.

Thus

the

adjusted

lower

level

becomes,

effectively,

the

base

to

which

the

upper

level

is

added

and

the

result

is

a

window

of

0

to

1

V

based

on

the

lower-level

threshold.

5.5.

INPUT

CIRCUIT

The

analog

input

signal

to

be

analyzed

is

furnished

through

CN1

on

the

front

panel

and

through

an

attenuator

network.

The

ATTN

switch,

SI,

on

the

front

panel

can

be

set

at

XI,

X10,

or

X100.

When

it

is

set

at

XI,

the

full

am

plitude

input

signal

is

furnished

to

a

peak

stretcher

and

through

a

divide-by-two

network

into

each

of

the

four

discriminator

circuits.

The

output

of

the

peak

stretcher

is

divided

by

two

so

that

the

original

input

amplitude

range

of

0

to

10

V

corresponds

to

a

0

to

5

V

range

at

the

input

to

each

discriminator

and

this

corresponds

directly

to

the

0

to

5

V

range

that

is

provided

for

each

comparator.

If

the

switch

is

set

at

X10

attenuation,

the

input

signal

is

divided

through

R1

and

R5

so

that

1/10

of

the

input

signal

amplitude

is

available

for

the

internal

circuits.

If

the

switch

is

set

at

X100,

the

signal

is

attenuated

to

1%

of

its

original

amplitude

by

division

through

R1

in

series

with

the

par

allel

network

of

R5

and

R3.

The

attenuator

output

is

applied

to

a

stretcher

circuit

that

stores

the

peak

amplitude

of

its

input

as

a

stretched

level

until

it

is

discharged.

The

discharge

signal

is

furnished

from

106-12

and

occurs

only

after

a

trigger

has

occurred

in

both

the

channel

A

and

channel

B

discriminator

out

puts

and

the

lower-level

discriminator

has

been

reset.

Because

of

this

logic,

if

the

channel

B-Fraction

selector

switch

on

the

front

panel

is

set

at

Bl

and

the

input

does

not

cross

zero,

the

channel

B

discriminator

will

not

be

triggered

and

the

module

will

lock

up

since

its

logic

can

not

be

reset.

Jumper

J1,

shown

on

the

schematic,

is

installed

during

a

test

adjustment

of

the

dc

zero

level

of

the

stretcher

and

is

removed

for

normal

operation.

See

Section

6.2

for

cali

bration

information.

5.6.

LOWER-LEVEL

DISCRIMINATOR

Integrated

circuit

package

IC3

is

the

lower-level

discrim

inator.

As

long

as

the

input

level

at

its

4

is

lower

than

the

reference

level

at

3,

the

output

at

9

is

high.

When

the

input

amplitude

rises

through

the

reference

level,

the

output

at

9

switches

to

the

low

state.

Then

when

the

input

amplitude

decays

back

through

the

refer

ence

level,

the

9

output

switches

back

to

high

again.

When

the

9

output

goes

low,

this

sets

flip

flop

IC4-6

and

IC4-3

high

to

identify

the

lower-level

trigger

point.

The

switch

to

high

at

IC4-3

is

furnished

through

an

output

generator,

Q18

through

Q22,

to

generate

a

NIM-standard

slow

positive

pulse

through

LL

Out

connector

CN6.

It

is

also

furnished

as

one

input

to

105-11,

where

a

decision

is

made

for

the

single-channel

logic.

With

both

inputs

high,

105-11

switches

to

low

to

identify

that

the

logic

is

satis

fied.

Unless

this

condition

is

cancelled

by

a

response

from

the

upper-level

discriminator

before

the

constant-fraction

circuits

are

triggered,

the

output

of

103-11

enables

the

gates

for

the

SCA

outputs.

To

prevent

multiple

firings

of

the

discriminator

near

the

threshold

level,

a

hysteresis

of

about

5

mV

is

furnished

to

the

lower-level

discriminator

by

R220

and

R219.

5.7.

UPPER-LEVEL

DISCRIMINATOR

Integrated

circuit

package

102

is

the

upper-level

discrimi

nator.

As

long

as

the

input

level

at

its

4

is

lower

than

the

reference

level

at

3,

the

output

at

9

is

high.

When

the

input

amplitude

rises

through

the

reference

level,

the

output

at

9

switches

to

low

and

sets

flip

flop

104-11

and

104-8,

with

104-11

going

high.

If

switch

S3

is

set

at

Normal

or

Window,

the

upper-level

discriminator

response

provides

a

low

from

105-8

to

cancel

the

logic

at

105-11

and

to

prevent

any

SCA

output

from

being

gener

ated.

If

switch

S3

is

set

at

Integral,

the

upper-level

re

sponse

is

not

used

at

103-11.

When

104-11

goes

high,

an

output

generator,

013

through

017,

triggers

and

generates

a

NIM-standard

slow

positive

pulse

through

UL

Out

connector

0N4.

A

5

mV

hysteresis

is

used

to

prevent

multiple

firings

near

the

threshold

for

102.

This

is

generated

by

R218and

R124.

5.8.

CHANNEL

A

DISCRIMINATOR

The

channel

A

discriminator

is

107.

The

input

signal

is

furnished

through

3

and

the

reference

level

is

fur

nished

through

4.

At

the

onset

of

the

input

pulse,

the

level

at

3

rises

faster

than

the

level

through

4

and

this

generates

a

low

output

at

9

and

a

high

at

11.

The

level

at

4

is

furnished

from

the

peak

stretcher

so

it

will

remain

at

a

fixed

level,

which

is

a

proportional

amplitude

with

reference

to

the

input

peak,

while

the

input

pulse

decays.

When

the

input

pulse

decay

crosses

the

reference

level,

107

is

reset

to

generate

the

channel

A

trigger.

Jumper

J3

on

the

printed

circuit

board

selects

which

of

the

three

fractions

is

effective

for

the

reference

level;

this

can

be

set

at

10%,

20%,

or

50%

down

from

the

peak

amplitude

(90%,

80%,

or

50%

respectively

of

the

peak

amplitude).

When

107

is

reset

and

its

11

goes

to

ground,

a

10-ns

negative

pulse

is

generated

from

108-15

through

Q23,

108-6,

and

DL1.

If

the

A

SOA

gate,

108-2,

has

been

en

abled

by

a

low

from

Q27A

(logic

is

satisfied)

the

output

from

IC8-15

triggers

a

current

switch

to

generate

a

NIM-

standard

fast

negative

output

pulse

through

CN3

on

the

front

panel.

5.9.

CHANNEL

B

DISCRIMINATOR

The

channel

B

discriminator

Is

109.

The

Input

signal

Is

furnished

through

3

and

the

reference

level

Is

fur

nished

through

4.

At

the

onset

of

the

Input

pulse,

the

level

at

3

rises

faster

than

the

level

at

4

and

this

sets

the

discriminator

with

a

low

at

9

and

a

high

at

11.

The

level

at

4

Is

furnished

from

the

peak

stretcher

so

It

will

remain

at

a

fixed

level,

which

Is

an

amplitude

pro

portional

to

the

Input

peak,

while

the

Input

pulse

decays.

When

the

Input

pulse

decay

crosses

the

reference

level,

109

Is

reset

to

generate

the

channel

B

trigger.

Switch

34

on

the

front

panel

selects

the

fractional

level

that

Is

effec

tive

for

the

4

reference

level;

this

level

can

be

set

at

10%

through

90%,

In

10%

Increments,

or

at

Bl

(equivalent

to

100%),

where

each

fraction

Is

measured

down

from

the

peak

amplitude.

When

109

Is

reset,

the

level

at

Its

11

goes

to

ground

to

Indicate

recognition

of

the

constant-fraction

point

on

the

decay

of

the

Input

pulse.

This

output

Is

furnished

to

an

EOL

gate,

Q27B

through

Q47.

This

serves

as

both

the

SOA

logic

gate

and

the

constant-fraction

trigger

gate,

and

must

be

enabled

from

105-11

In

order

to

respond

to

the

OF

trigger.

With

the

logic

satisfied,

the

trigger

forces

the

collector

of

Q41

high

and

It

will

remain

high

until

It

Is

reset.

The

high

transition

at

Q410

Is

furnished

through

the

delay

circuitry

that

Includes

Q28,

Q29,

Q42,Q33,

Q32,Q30,

and

Q31.

The

Input

pair,

Q28

and

Q29,

Is

biased

from

Q290

and

Q29D

operating

as

a

temperature

compensated

cur

rent

source.

Normally

028

Is

off

and

its

collector

Is

In

the

high

state.

At

the

Input

pulse,

028

turns

on

and

029

turns

off.

The

low

transition

at

the

collector

of

028

Is

fed

through

O30

to

storage

capacitor

076.

Thus

the

029

base

voltage

Is

stepped

In

a

negative

direction

through

076.

Oapacltor

076

Is

charged

by

temperature

compensated

source

032

and

033,

and

the

rate

Is

determined

(for

In

ternal

strobe

operation)

by

front

panel

Delay

control

R189.

When

the

storage

capacitor

has

charged

back

to

the

point

where

the

base

of

029

Is

at

the

same

level

as

the

base

of

028,

029

turns

on

again

to

switch

the

collector

of

029

to

the

low

state.

When

the

collector

of

029

switches

to

the

low

state,

an

output

for

channel

B

will

be

generated.

For

internal

strobe

operation,

1010-15

Is

enabled

by

+5

V

through

D17.

When

0290

goes

high

at

the

trigger

Input,

IC10-15

Is

high

and

IC10-9

Is

low,

so

IC10-3

Is

low.

At

the

end

of

the

delay,

when

0290

goes

low,

this

switches

IO10-9

to

high

and

IO10-15

to

low.

For

10

ns,

both

Inputs

to

1010-3

are

high

so

there

Is

a

10-ns

positive

pulse

gen

erated

at

1010-3.

This

pulse

triggers

output

generator

046,045,

036,037,

and

038

through

066

to

furnish

a

NlM-standard

slow

positive

pulse

through

0N7

on

the

rear

panel

and

0N8

on

the

front

panel.

The

1010-3

output

Is

also

Inverted

through

044

to

trigger

the

current

switch

that

generates

the

NlM-standard

fast

negative

output

through

0N9.

For

external

strobe

operation,

the

charge

circuit

for

076

Is

through

R188,

so

029

Is

turned

on

after

10

If

It

has

not

already

been

turned

on

by

an

external

strobe

pulse.

While

029

Is

turned

off,

gate

IO10-15

Is

enabled

at

Its

13and

will

trigger

an

output

pulse

If

a

NlM-standard

slow

posi

tive

pulse

Is

furnished

through

0N3

on

the

rear

panel.

The

strobe

Input

Is

coupled

through

025

and

026

to

start

the

output

pulse

generation

through

1010-15

In

the

same

manner

as

described

for

Internal

strobe

operation.

At

the

leading

edge

of

the

strobe

Input,

the

signal

through

033

and

034

will

quickly

charge

076

and

turn

off

029

to

reset

the

system.

If

029

Is

turned

on

by

076

before

a

strobe

Is

furnished,

gate

IO10-15

will

be

disabled

so

that

the

strobe

will

have

no

effect.

5.10.

RESET

CIRCUIT

An

Internal

reset

Is

generated

at

106-12

when

all

three

Inputs

are

high.

The

Input

at

2

goes

high

when

both

channel

A

and

channel

B

discriminators

are

reset

(the

trigger

point).

The

Input

at

13

goes

high

when

the

lower-level

discriminator

Is

reset

by

having

the

Input

pulse

amplitude

fall

back

through

the

reference

level.

The

104-3

level

stays

high,

latched,

until

the

flip

flop

Is

reset,

so

the

Input

to

1

of

106-12

Is

also

high.

Thus,

after

all

three

events

have

taken

place

(lower-level

dis

criminator

reset

and

both

channels

triggered)

the

Inputs

to

106-12

are

all

high

to

generate

reset.

The

reset

signal

Is

furnished

to

104-6

and

104-8

to

reset

both

discriminator

latches

and

to

the

Input

stretcher

circuit

to

discharge

Its

stretched

peak

level.

5.11.

DC

POWER

Input

power

from

the

bin

and

power

supply

Is

accepted

through

the

module

connector

on

the

rear

panel.

The

552

operates

on

166

mA

through

the

+12

V

circuit,

166

mA

through

tne

-12

V

circuit,

83

mA

from

+24

V,

and

83

mA

from

-24

V.

Internally

the

+12-V

source

Is

used

to

generate

a

regu

lated

+5

V

by

1011

and

-12

V

Is

used

to

generate

a

reg

ulated

-5

V

by

1012.

6.

MAINTENANCE

AND

CALIBRATION

6.1.

GENERAL

The

basic

performance

of

the

552

Pulse-Shape

Analyzer

and

Timing

SCA

can

be

inferred

from

its

operating

responses.

If

the

unit

fails

to

respond

properly

at

any

time,

use

the

information

in

Section

5

to

identify

the

probable

fault.

The

block

diagrams

of

Fig.

5.1

and

552-

0101-B1

and

the

schematic,

552-0201-S1,

identify

all

of

the

circuits

in

the

instrument.

6.2.

STRETCHER

CALIBRATION

There

is

a

provision

for

calibration

of

the

stretcher

cir

cuit.

Potentiometers

RISand

R29,

mounted

on

the

printed

circuit,

provide

this

calibration.

Use

the

following

pro

cedure:

1.

Remove

jumper

at

location

J1

from

A

to

B

and

insert

In

B

to

C.

2.

Set

potentiometer

R18

fully

counterclockwise,

as

viewed

from

the

top.

3.

With

no

input

signals

into

the

552,

adjust

R27

to

obtain

0

V

±

1

mV

at

TP1.

4.

Remove

jumper

at

location

J1

from

B

to

0

and

insert

in

A

to.B.

.5.

With

no

inputsignalsintothe552,adjustR18toobtain

D

V

±

1

mV

at

TP1.

Leave

jumper

in

position

A

to

B

for

normal

operation.

6.3.

WALK

CALIBRATION

A

Walk

Adj

control

is

furnished

separately

for

each

of

the

two

output

channels.

R86

serves

channel

A

and

R100

serves

channel

B.

Use

the

following

procedure

after

the

stretcher

has

been

calibrated

as

described

in

Section

6.2.

1.

With

the

552

turned

on

and

with

no

input

signal,

adjust

R86

to

a

point

where

the

dc

levels

at

pins

3

and

4

of

107

have

a

difference

of

0

V.

Adjust

R100

so

the

dc

levels

at

pins

3

and

4

of

109

have

a

difference

of

0

V.

2.

Set

the

front

panel

ATTN

switch

at

XI,

the

Mode

switch

at

Int,

and

use

Internal

Strobe.

Adjust

the

Lower-

Level

control

to

its

minimum

setting.

3.

Furnish

a

10-V

shaped

pulse

into

the

552

Input

con

nector.

Use

whatever

shaping

will

be

used

for

subsequent

operation.

4.

Examine

the

response

time

for

each

channel.

5.

Switch

the

ATTN

to

XI0,

and

check

the

response

time

for

walk.

If

any

is

noted,

adjust

R86

carefully

for

channel

A

or

R100

for

channel

B.

6.

Switch

the

ATTN

to

XI00

and

check

for

walk.

If

necessary,

adjust

R86

for

channel

A

and

R100

for

chan

nel

B.

7.

Use

all

three

settings

of

the

ATTN

switch

and

com

pare

the

timing

responses.

The

final

adjustment

of

R86

and

R100

should

provide

minimum

walk.

The

input

attenuator

is

a

high-quality

circuit

for

this

application

and

contributes

nominally

less

than

1

ns

to

the

walk.

8.

Return

the

ATTN

switch

to

X1

for

normal

operation.

6.4.

LOWER-LEVEL

CALIBRATION

The

minimum

level

to

which

the

Lower-Level

front

panel

control

can

be

set

is

40

mV.

This

can

be

calibrated

by

adjusting

R54

on

the

printed

circuit

board

as

follows:

1.

Set

the

Lower-Level

control

at

004/1000

dial

divisions.

2.

Set

the

ATTN

switch

at

XI.

3.

Furnish

a

40

mV

input

pulse

into

the

552.

4.

Adjust

R54

as

required

to

half-trigger

under

these

conditions.

6.5.

FACTORY

REPAIR

This

instrument

can

be

returned

to

the

ORTEC

factory

for

service

and

repair

at

a

nominal

cost.

Our

standard

procedure

for

repair

ensures

the

same

quality

control

and

checkout

that

are

used

for

a

new

instrument.

Always

contact

Customer

Services

at

ORTEC,

(615)

482-4411,

before

sending

in

an

instrument

for

repair

to

obtain

shipping

instructions

and

so

that

the

required

Return

Authorization

Number

can

be

assigned

to

the

unit.

Write

this

number

on

the

address

label

and

on

the

package

to

ensure

prompt

attention

when

the

shipment

reaches

the

ORTEC

factory.

BIN/MODULE

CONNECTOR

ASSIGNMENTS

FOR

AEC

STANDARD

NUCLEAR

INSTRUMENT

MODULES

PER

TID-20893

(Rev

4)

(adopted

by

DOE)

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

22

Reserved

Pins

marked

(")

are

installed

and

wired

in

EG&G

ORTEC's

4001A,

40018,

4001C.

401A,

and

4018

Modular

System

8ins.

Pins

marked

(*)

and

(**)

are

installed

in

EG&G

ORTEC-HEP

M250/N

and

M350/N

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EG&G ORTEC 552 Service manual

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