Current Pulse Preamplifiers for Use with Fission Counters

NE Standard
NE C 15-3T
October 1974
Canceled July 1996
CURRENT PULSE PREAMPLIFIERS FOR USE WITH FISSION
COUNTERS
INCLUDING AMENDMENTS 1 AND 2
No Replacement

CURRENT PULSE
FOR USE WITH
Any further distribution by any holder of this docu-
ment or of the data therein to third parties represent-
ing foreign interests. foreign governments, foreign
companies and foreign subsidiaries or foreign divisions
of U. S. companies should be coordinated with the
Director, Division of Reactor Development and Tech-
nology, U. S. Atomic Energy Commission.
Division of Reactor Development and Techn
United States Atomic Energy Commission

\ /'
,'
//
CAUTION ,' JUNE 1991
This standard is
It has not been maintained and m ent.
Before this
31
\

RDT STANDARD RDT c 15-3~, Amendment 2
UNITED STATES ATOMIC ENERGY COMMISSION
DATE October 1974
DIVISION OF REACTOR RESEARCH AND DEVELOPMENT PAGE 1 OF 1
CURRENT PULSE PREAMPLIFIERS FOR USE WITH FISSION COUNTERS
AMENDMENT 2
This amendment forms a part o
dated August 197 1,
Page 18, 4.5.8: Change the th to read:
input can then be
to the preamplifier
= the preamplifier voltage gain (also equal to preamplifier
current gain)
B .W . = the noise bandwidth of the amplifier filter (one MHz for
CR-RC filter time constant of 0.5 psec)
R = the resistor value connected to the input of the
preamp1 if ier .
(For filter time constants other than 0.5 pec , the B .W. can be calculated
from the expression B .W. equals 1/(2~) where T is the filter time constant
in seconds.) The noise current spectral density obtained shall be less
than 15 pA per *. The noise current spectral density obtained for the -
Type B preamplifier and either output of the Type C preamplifier shall
be less than 30 pA per F.

R D T S T A N D A R D
RDT C 15-3T Amendment 1
UNITED STATES ATOMIC ENERGY COMMISSION
DIVISION OF REACTOR DEVELOPMENT AND TECHNOLOGY
Date
Page
June 1973
1 of 2
CURRENT PULSE PREAMPLIFIERS FOR USE WITH FISSION COUNTERS
Page 1, Scope: Add the
Two gain options for
Page 1, 1.1: Add the f
Two gain options
gain (high or lo
Page 4, 3.
This amendment forms a part o
Page 4, Table 1: Change to read:
Table 1
Pulse Polarity and Current Gain Requirements
for Type A, B and C Preamplifiers
Input Terminal Output Terminal
Type Polarity Polarity Current Gain(+ 10%)
Input 1 Input 2 output 1 output 2 output 1 output 2
A h'egative n'egative 500*
B n'egative Eegative 250*
B Positive Negative 250k

Input Terminal Output Terminal
RDT C 15-3T
Amendment 1 -
Page 2
Type Pclarity Polarity Current Gain (+ 10%)
Input 1 Input 2 Output 1 Output 2 output 1 output 2
C Negative Negative Positive 125* 125*
C Positive Negative 125*
* Values shown are for the "low gain" option. ption, double
the values shown.
5. Page 4, 3.2.2: Change first senten
The pulse rise time (time from when measured
with an input pulse of 1.0 nse time and less than 5% overshoot
shall be less than 10.0 nsec.
6. Page 6, 3.3.3: Change 0 ma" in next to last sentence:
7. Page 8, 3.3.7: "3.5.10" in last sentence, 3rd paragraph
8. Page 8, .Ill1 to "3.5.10" in last sentence.
9. Page 16, paragraph, change first sentence to read:
at any convenient pulse rate and a
pulse width of 100 nsec, apply a 0.4 mV pulse to a low gain preamplifier
input (0.2 mV for a high gain preamplifier).
In the second paragraph, change first sentence to read:
Increase the input signal to 0.8 mV for a low gain type B preamplifier
(0.4 mv for a high gain preamplifier) and to 2.0 mV for a low gain type
C preamplfier (1.0 mV for a high gain preamplifier).
10. Page 17, 4.5.3: Change "5.0 nsec" to 10.0 nsec" in third sentence.
11. Page 18, 4.5.9: In the first paragraph, third sentence, change to read:
Adjust the pulse generator for a 100 nsec pulse width, approximately a
10 kHz pulse rate and apply a 0.5 mvpulse to the input of a low gain -
preamplifier (0.25 mV to a high gain preamplifier).
12. Page 22, 4.5.13: In the first sentence after the formula, change
" (Borninally 400) " to 'I (Nominally 500 or 1000) " .
13. Page 24, 6.2.a: Change to read:
a) Preamplifier type and gain (high or low) . (Section 1.1 and 3.2.1) .

R D T S T A N D A R D
UNITED STATES ATOMIC ENERGY COMMISSION
DIVISION OF REACTOR DEVELOPMENT AND TECHNOLOGY
- -
CURRENT PULSE PREAMPLIFIERS FOR USE WITH FISSION COUNTERS
SCOPE
1.1 Classification
1.2 Applicability
1.3 Definitions
APPLICABLE DOCUMENTS
2.1 AEC-RDT Standards
2.2 Military Standards
2.3 Federal
2.4
3.1 Genera
3.5 Mater
TABLE OF CONTENTS
3.7 General Assembly and Layout Design
3.8 Reconunended Circuit Design for an Input Stage
3.9 Identification
3.10 Maintenance Manual
4. QUALITY ASSURANCE REQUIREMENTS
4.1 Quality Assurance Program
4.2 Design Approval
4.3 Material Certification
4.4 Alternate Materials
4.5 Tests
4.6 Test Result Certification
4.7 Test Instrument Certification
5 . PREPARATION FOR DELIVERY
6. NOTES AND ORDERING DATA
6.1 Bid Proposal
6.2 Ordering Data
RDT C 15 - 3T
Date August 1971
Page

APPENDIX A
APPENDIX B
APPENDIX C
RDT C 15-3T
Page
2 5
2 7

R D T S T A N D A R D RDT C 15-3 T
UNITED STATES ATOMIC ENERGY COMMISSION
DIVISION OF REACTOR DEVELOPMENT AND TECHNOLOGY
CURRENT PULSE PREAMPLIFIERS FOR USE WITH FISSION COUNTERS
1. SCOPE
Date August 1971
Page 1 of
This standard covers three types of ended input
and output, differential input and single
and output) for use with fission counters
the current pulse of the counter. It performance and
the tests to determine this
overall construction guides are given to vity of operation and
good shielding against
Various connections of the £is ias potential to the differ-
ent preamplifiers along with a sure the counter dc current are
presented to acconawdate both guarded fission counters.
A filter for the cou r b i w t i a l is an integral part of the pre-
amplifier.
The counter b&\he supplies for preamplifier power ire not
a part of the prea
and output cables are nominally 50 ohms for the
100 ohms for the twin-conductor type. This
other impedances.
1.1 Classification. Preamplifiers will be one of the following types
as specified in the Ordering Data.
Type A (single-ended input and single-ended output) - This pre-
amplifier obtains its signal from a single 50-ohm coaxial
cable and develops an amplified output signal across an
external 50-ohm load.
Type B (differential input and signal-ended output) - This pre-
amplifier obtains two signals of identical size and shape
but of opposite polarity from two 50-ohm coaxial cables
and develops an amplified output signal across an external
50-ohm load. (In some ca'ses the input signal may be ob-
tained from a 100-ohm twin-conductor cable. )
Type C (differential input and differential output) - This pre-
amplifier is similar to Type B except that it develops
two amplified output signals of identical shape but
opposite polarity across two separate 50-ohm loads. (In
some cases it may be required that the output drive a
100-ohm twin-conductor cable.)
3 0

RDT C 15-3 T
Page 2
1.2 A~vlicability. These preamplifiers will be used to amplify narrow
current pulses from fission counters to obtain high efficiency detection of
neutrons in garmna fields in excess of 106 R/hr. The length of the input
cable to the preamplifier is limited only by transmission losses and external
noise pick-up.
Type B and Type C preamplifiers, with more complex and expensive cabling,
exploit the high common-mode rejection capabilities of
it is required that both the cabling
highly balanced condition. Twin-conductor
and output
common shield.
frequency response than coaxial
provised adaptations of coaxial hardware.
The use of input cables with imp than 50 ohms is possible
provided the input impedance of the p s modified accordingly.
The noise density specified a cable impedance of 50 ohms
increasing for values above 50.
ohms. However, with impedances it is theoretically
se ratio provided the time constant
is small compared to
cable losses are com-
parable.
will provide a lighter
However, the 50-ohm
impedance is more compatible with existing high frequency equipment such as
amplifiers, discriminators and attenuators.
These preamplifiers can be used with counters other than the fission type
provided the 1000 volt rating of input coupling capacitor and filter network
for counter bias supply is not exceeded. Use with counters having electron
collection times greater than 200 nsec is not recomended. The signal-to-
noise ratio is degraded and the input coupling time-constant (10 psec minimum)
is not sufficient to reduce the undershoot to a tolerable level. (The limit-
ations of the voltage rating of the input coupling capacitor and input coup-
ling time constant can be eliminated with a guarded type counter since a direct
current connection to the preamplifier is possible.)
1.3 Definitions
1.3.1 Supplier. The individual or company entering into a contract,
subcontract, or purchase order issued by the purchaser.
1.3.2 Purchaser. The agency responsible for issuance and adminis-
tration of a contract, subcontract, or purchase order imposing this standard
or portions thereof.

2 . APPLICABLE DOCUMENTS
RDT C 15-3T
Page 3
The following documents are a part of this standard to the extent indicated
where they are cited in the text. The issue of a document in effect on the date
of the order, including any amendments also in effect on that date, shall apply
unless otherwise specified. Where the standard appears to conflict with the
requirements of a reference document, the supplier shall call it to the attention
of the purchaser for resolution.
2 -1 AEC-RDT Standards
RDT F 2-2T, Quality Assurance
2.2 Military Specifications
Mil-R-55182D, Resistors, Fixed, General
Mil-C-39014B, Capacitors, Dielectric (General Purpose) ,
Mil-C-11015D, Capacit ramic Dielectric (General Purpos'e) ,
Mil-C-25D,
Mil-P-13949C, Plastic Sheet, Laminated, Copper Clad, (For Printed Wiring)
Mil-W- 16878D (Navy) , Wire, Electrical, Insulated, High Temperature
Mil-C-39012B, Connectors, Coaxial, Radio Frequency, General Spec if ications
For
Mil-C-26482E, Connectors, Electric, Circular , Miniature, Quick Disconnect,
Environment Resisting
2.3 Federal Specifications
QQ-P-416b, Plating, Cadmium (Electrodeposited)
QQ-S-571d, Solder; Tin Alloy; Lead-Tin Alloy; and Lead Alloy
2.4 American Society for Testing and Materials Specifications
ASTM A620, Carbon Steel Sheet, Cold-Rolled, Drawing Quality, Special
Killed.

3. TECHNICAL REQUIREMENTS
RDT C 15-3 T
Page 4
3.1 General. The preamplifier shall be an electronic device construc-
ted of silicon transistors and high quality circuit components and assembled
in a double-walled metal enclosure of high conductance to shield it from
external electrical fields and ground currents.
and its input e of the
cable. The input signal to the
across the cable by the current pulse of the fissi
this voltage
degradation caused from
ance time constant and
3.2 Performance
3.2.1 Pulse Current Gain.
a rectangular pulse de and any convenient pulse rate
shall be according to Table 1. f output current shall be indi-
cated by the voltage
put terminal and sure of the input current shall be
deduced from the nput terminal and the assumption that
the input
v TABLE 1
Pulse Polarity and Current Gain Requirements for Type A, B, and C Preamplifiers
Type Input Terminal Output Terminal
and
Polarity Polarity Current Gain (go%)
No. 1 No. 2 No. 1 No. 2 No. 1 No. 2
A Negative Negative 400
B Negative Negative 200
B Positive Negative 200
C Negative Negative Positive 100 100
C Positive Negative Positive 100 100
3.2.2 Pulse Rise Time. The pulse rise time (time from 10% to 90%
of final amplitude) when measured with an input pulse of 1.0 nsec +lo% rise
time and less than 5% overshoot shall be less than 5.0 nsec. The output
pulse shall be measured across a 50-ohm resistor connected between the output
terminal and signal ground. The overshoot shall not exceed 10%. The measurement
shall be made on an output signal of 200 mV ~25% with polarities as given
in Table 1.

RDT C15-3T
Page 5
3.2.3 Integral Nonlinearity. The preamplifier shall be capable of
driving a 50-ohm resistor connected between the output terminal and signal
ground to 400 mV with less than 1.09. integral nonlinearity. The pulse polar-
ity shall be as given in Table 1.
3.2.4 Output Saturation Level. The preamplifier saturation level
shall be a minimum of 600 mV when driving a 50-ohm resistor connected be-
tween the output terminal and signal ground. The shall be
as given in Table 1.
3.2.5 Output Pulse
shall be measured with a
-
+5% and at a pulse rate
pulse as observed across
pulse.
lifier shall be such
up to 10 MHz. The measurement s
having a width of 50 nsec
+lo% output pulse across a
-
output terminal) when referred to either input shall be less than 30 pA rms
per ,/HZ.
3.2.8 Gain Stability. The gain change with temperature when measured
between 25OC to 66%. shall be less than 0.05%/OC with the gain at 25OC as a
reference.
3.2.9 Input Impedance. The input impedance shall be such that the
reflections from the input as observed at the pulse generator terminals shall
be less than +lo% of the applied input signal. The test pulse waveform shall
have a rise time of 1.0 nsec 50% with less than 5% overshoot and shall be
applied to the preamplifier input with a coaxial cable having a characteristic
impedance of 50 ohms.
3.2.10 Noise Imnunitv. The shielding shall be such that a current
pulse of 100 rnA through the outside enclosure of the preamplifier shall not
result in an output pulse above the noise level when measured with a O.lO-psec
CR-RC filter. The current test pulse shall be 100 nsec wide +10% and have a
rise time of 1.0 nsec +10% and less than 5% overshoot.
3.2.11 Input Protection. The input shall be capable of discharging
a 0.01 pF capacitor which is charged to either positive or negative 1000 volts
without damage to the preamplifier.

RDT C 15-3 T
Page 6
3.2.12 Common-Mode Rejection. The commonmode rejection for the
Type B and Type C preamplifiers shall be in excess of 40 dB from 50 kHz to
20 MHz.
3.2.13 Environmental Conditions. The performance of the preampli-
fier as specified in Sections 3.2.1 and 3.2.2 shall be retained for the fol-
lowing conditions :
3.3 Electrical
(50.05 V), +12 V (20.
1. After 24 hours of operation at 40' a relative
humidity of 90 to 95%.
humidty .
coupling time constant
age rating of the input coupling
counter bias potential) and shall be as
0.005 V peak to peak on each supply. The current from each supply shall not
exceed 100 mA. Thes'e voltages shall be obtained from power supplies external
to the preamplifier and the regulation applies to the voltage at the terminals
of the power supplies.
3.3.4 Fission Counter Bias Filter Network. The preamplifier shall
contain a filter network for the fission counter bias potential with a minimum
voltage rating of 1000 volts dc. It shall consist of a minimum of three equal
RC (low pass) sections with a total series resistance of not less than 15 x 103
ohms. The capacitor values shall not be less than 0.01 pF and shall be as speci-
fied in Section 3.5.4. All resistors shall be as specified in Section 3.5.1.
3.3.5 Bias Supply and Fission Counter Connection. The bias supply and
fission counter connection shall be one of the following types as specified in
the Ordering Data. Refer to Fig. 1 for description of the various types.
Type AUG - Type A preamplifier with unguarded counter
Type AG - Type A re amplifier with guarded counter
Type BUG or Type CUG - Type B or Type C preamplifier with unguarded
counter
Type BG or Type CG - Type B or Type C preamplifier with guarded counter.

RDT C 15-3 T
Page 8
3.3.6 Test Point for Bias Voltage. A test point shall be available
to monitor the bias voltage. The test voltage shall be obtained from a volt-
age divider network as shown in Fig. 1. All resistors in this network shall
be as specified in Section 3.5.2. The connector for this test point shall be
as specified in Section 3.5.10.
3.3.7 Test Points for Fission Counter DC Current. Test points shall
be available to monitor the fission chamber dc current
with the normal operation of the counter.
For the unguarded counter, the test points of two jacks
(with voltage ratings in excess of 1000 volts dc
output of the bias filter network along with a or a convenient
ground point as shown in Figs. 1A and 1C.
R
For the guarded counter, the consist of a coaxial
connector connected to a diode clamp 1B and ID. This
conn'ector shall be as specified in S
.
available to apply a test signal
such inputs shall be
required for the impedance of this input
ac coupled, the time
a source impedance
of 50 ohms.) This capable of withstanding voltages of 250 volts.
3.3.9 Input ~ihA Connector. A coaxial connector as specified in
Section 3.5.11 shall be supplied for the input signal.
preamplifier shall require two such connectors.
The Type B and Type C
3.3.10 Output Signal Connector. A coaxial connector as specified in
Section 3.5.10 shall be supplied for the output signal. The Type C preamplifier
shall require two such connectors.
3.3.11 Power Supply Connector. A connector shall be provided to apply
power to the preamplifier. A type as described in Section 3.5.12 is recommended.
This connector shall be as specified in the Ordering Data.
3.3.12 Counter Bias Connector. A connector as specified in Section
3.5.11 shall be supplied to apply a counter bias potential.
3.3.13 Termination Resistor For Counter Bias Cable. This resistor is,
shown in Fig. 1B as resistor R and shall be as specified in the Ordering Data.
3.4 Enclosure. The enclosure for the preamplifier shall be double-
walled box with inner and outer boxes electrically insulated. (See Fig. 2 for
illustration.)

BU1LD;NC
GROUND A
REMOVABLE COVERS
?. 3
it--- l
1
ID3 NOT S'iOWNl
FIGURE 2
REMOVABLE :OVERS
ENCLOSURE AND GENERA1
RDT C 15-3T
Page 9
INSULATOR
INPUT CONNECTOR
@ our~ur COKNE~TOR
@ POWER CONNECTOR
@ COUhTER BIAS CONNECTOR
@BIAS FILTER CGKFLPTMENT
@COL\TEQ aiis CO~IYECTOR
0 IhPCIT TLST COhNECTOR

RDT C 15-3 T
Page 10
3.4.1 Hole for Invut Signal Cable in Outer Box. A hole Dl shall be
located on the outer box to permit the mounting of a. fitting for an integral
connection to the external shield of the input cable. (This shield may be
the outer shield of a triaxial cable, the outer shield of a multiple shielded
cable, or the outer surface of a solid shield.) This hole shall be specified
in the Ordering Data as,
I$&%
Dl - (Number Required) - (Inches Dia
3.4.2 Hole for Input Signal Cable in Inner D2 shall be
located on the inner box to permit the optional nput connector
(other than that specified in Section fo an.integra1
connection to the rying shield may be
a multiple shielded
shall be specified
in the Ordering Data as,
es Diameter)
3.4.3 Hole for Output&alB,VJin Inner Box. A hole D3 shall be
located on the inner b ng of an output signal connector other
than that specified in
Ordering Data as,
This hole shall be specified in the
3.4.4 KW equired) - (Inches Diameter)
Hole fhbwer, Output Signal, and Counter Bias Cables in
Outer BOW A hole D4 shall be located on the outer box to
permit the mounting of a fitting for an integral connection to the external
shield of the cable group consisting of the output signal, power and counter
bias cables. This hole shall be specified in the Ordering Data as,
D4 - (Inches Diameter)
3.4.5 Covers for the Inner and Outer Boxes. The top and bottom sides
of the inner and outer boxes shall have removable covers to permit access to
both sides of the printed circuit boards.
3.4.6 Physical Dimensions of Inner Enclosure. The height of the
inner enclosure shall not exceed 2-112 inches and the total volume shall not
exceed 120 cubic inches.
3.4.7 Physical Dimensions of Outer Enclosure. The outer enclosure .
shall have a size which will permit easy connection and disconnection of
cables to the preamplifier.
3.5 Materials
3.5.1 Resistors. All resistors except as noted in Section 3.5.2 shall
be of the film, (high stability) type as specified in Mil-R-55182D. All resis-
tors shall conform to the 21.0% resistance tolerance and the 2100 parts/milli~n/~C
temperature characteristic and have solderable terminals. The outer impregnation
shall be of the conformal type with one or two coats of high temperature epoxy

RDT C 15-3 T
Page 11
enamel. The failure rate level shall not exceed 1.0%/1000 hour of operation.
3.5.2 Resistors (for Counter Bias Test)'. These resistors will have
a minimum of a 114 watt rating for an ambient temperature of 60°C. They will
have a tolerance of 21.0% and a 2200 parts/million/"C temperature characteristic
and solderable terminals. The voltage rating will not be less than 1000 volts
dc with a voltage coefficient not to exceed 25 parts/million/volt.
h
3.5.3 Capacitors (~e~amic). A l l ceramic c@ ors except as noted
in Section 3.5.4 shall be of a type as specified 014B. The capacitor
tolerance shall be 210%. The rated temperatu ration shall be -15
to +85'C. The maximum change in capacitance fer ce) over this range
shall be within 95% with no voltage appli n +15% and -25% with
maximum rated voltage applied.
1000 hours of operation.
The fa shall not exceed 1.0%/
3.5.4 Capacitors (for m o n c&n\er bias filterl. The capacitors
for the fission counter bias fi~t(e~shall%dof a type as specified in Mi1-C-
11015D. The capacitor shall rance of 220% and a voltage rating of
1000 volts dc. The rated nge of operation shall be -55.to +85OC.
The maximum change in capa reference) over this range shall be
within +30% and -70%
maximum rated volt
e applied and within +30% and -%OX with
input coupling). The capacitor for the input
s specified in Mil-C-25D with axial wire leads.
lerance of ~10% and a voltage rating of 1000 volts
nge of operation shall be 3 5 to +85'C. The
maximum change in capacitance (25'C reference) over the rated temperature
range and with maximum rated voltage applied shall oe within +7.5% and -10%.
3.5.6 Capacitors (electrolytic). All electrolytic capacitors shall
be tantalum with the solid electrolyte as specified in Mil-C-39003A. The
capacitor tolerance shall be 220%. The failure rate level shall not exceed
1.0%/1000 hours of operation.
3.5.7 Transistors. All transistors shall be of the silicon planar
expitaxial type.
3.5.8 Diodes (conventional). All conventional diodes shall be of
the silicon type.
3.5.9 Printed Circuit Board. The printed circuit board shall he of
the plastic sheet, laminated, copper clad type as specified in ~il-P-13949~,
using Type GH base material with cladding on both sides. The copper-foil
thickness of each side shall be 2 ounces per square foot (0.0028 inch nominal
thickness). The nominal overall thickness of the sheet shall be 1/16 (0.062)
inch.
3.5.10 Coaxial Connector (Type TNC). This connector shall be as
specified in Mil-C-35012B with a tarnish-free, silver-plated, brass shell.

RDT C 15-3T
Page 12
3.5.11 Coaxial connector (Type N). This connector shall be as
specified in Mil-C-35012B with a tarnish-free, silver-plated, brass shell.
3.5.12 Connector (power supply). This connector shall be a miniature,
circular type conforming to Mil-C-26482E with gold-plated contacts and a shell
made of a ferrous alloy material.
3.5.13 Hook-Up Wire. The to Mil-W-16878D
(Navy). The conductor shall be made up of round cross- individually
silver-plated, soft-annealed copper wires. The
temperature rating and a voltage rating of 600 volt
3.5.14 Solder. All solder
QQ-S-571d with an alloy of 60% tin,
Type R, rosin. No other soldering fluxes
be made of 20 gauge
(0.0359 inch), carbon steel sheet, c quality, special killed
as specified in ASTM A 620-68.
3.6 Construction. The obtain approval of the fabrication
tion (see Section 4.2).
recessed contacts.
Each transistor shall be mounted in a
closed entry and
3.6.2 integrahdbircuit Mounting. Each integrated circuit shall be
mounted in a Teflon insugted socket with gold-plated, beryllium copper, re-
cessed contacts.
3.6.3 Printed Circuit Board Plating. The printed circuit board shall
be gold-plated with a plating thickness of 0.0002 inch minimum and 0.0003 inch
maximum. The gold shall be 23 carat hard plate and 99.5% pure.
3.6.4 Enclosure Plating. After all drilling, bending, and welding or
silver soldering, the enclosure shall be plated with 0.0005 inch thick cadmium
as per Federal Specification QQ-416b with Type I plating. The final finish
shall be a post-plating bright dip followed by a lacquer dip.
3.6.5 Input Cable Terminating Resistor. This resistor or resistors
shall be located to permit easy removal and installation,
3.6.6 Input Cable Connection. A gold-plated, split-lug terminal shall
be available to make a connection to the input cable center conductor.
3.6.7 Removable Covers for the Enclosure. Removable covers shall not
create long slits or cracks. Covers shall either be the overlapping type with
anti-rattle clips or a flat plate fastened down with screws at a maximum
spacing of 2.0 inches.
3.7 General Assembly and Layout Design. The general assembly and layout
shall have the following features. (See Fig. 2 for illustration.)

1. The input connectors shall be mounted on the inner box.
2. Connectors for the output signal, preamplifier power and
counter bias potential shall be mounted on the inner box.
3. The ground planes of all printed circuit boards shall be
firmly soldered to the walls of the inner box.
4. Each amplifier section (three shown in Fig. 2) and the counter
bias filter shall be partitioned off
soldered to the ground plane and
of the inner box.
5. Each amplifier section shall be s
filters on the power lead.
6. Each amplifier section shall b
return lead.
3.9 Identification.
OUT SIG (for output signal)
PWR (for preamplifier power)
HV OUT (for bias connection to counter)
HV IN (for counter bias supply input)
HV TEST (for counter bias test)
DC OUT (for dc current output)
IN TEST (for test input)
DC (+) (for high side dc current test point)
DC (-) (for low side dc current test point)
GND (for ground test point)
a separate power
er stamped or printed with oil, grease
identified on the printed circuit board with
3.10 Maintenance Manual. The supplier shall supply three copies of a
maintenance manual for each preamplifier type purchased. This manual shall
include :
1. Complete drawing of the circuit,
2. Complete drawing of all metal work,
3. Complete drawing of the printed circuit board layout,
4. Voltage and waveform chart for the circuit. (This may be part
of Item I.),
5. Details for all tests and adjustments,
6. Complete parts list.

4. QUALITY ASSURANCE REQUIREMENTS
RDT C 15-3 T
Page 14
4.1 Quality Assurance Program. The supplier's quality assurance prog-
ram shall conform to Sections 1, 2, 3, 4, 5, and 8 of RDT F2-2.
4.1.1 Program Plan. A quality assurance program plan shall be pre-
pared by the supplier and submitted to the
specified in Section 6.1. The requirements
dance with Section 2.2 of RDT F2-2.
4.2 Design Approval. The supplier
purchaser the following designs for approval,
1. Preliminary design of
bid proposal as specified
2. Fabrication design of
cation shall not be st
design has been extend
unapp d resubmitted for approval.
material substitution.
ot covered by this standard, the certifi-
approval by the purchaser.
The supplier may recommend alternate materials
e considers a substitute material will produce an
4.5 Tests. The following tests shall be performed by the supplier unless
otherwise specified in the Ordering Data. Each preamplifier shall pass the
specified tests for acceptance. If the preamplifier has been constructed for
an integral connection to the input cable, a connector of the type specified
in Section 3.5.10 shall be temporarily mounted to perform all tests requiring
connections to the preamplifier input.
4.5.1 Test Equipment. The supplier shall utilize test equipment
sufficient to determine conformance of the preamplifier to applicable require-
ments. The test instruments shall be adjusted and calibrated against standards
having known valid relationship to nationally recognized standards, when such
exist. If no national standards exist, the supplier shall document the basis
for his calibration. Refer to Section 5.8 of F2-2. Suggested test instruments
are listed.
4.5.1,l Oscillosco~e (sampling). Used to measure gain, rise time,
and input impedance. (Tektronix 661 Sampling Oscilloscope or equal).
1. Vertical sensitivity - 10 mV/cm
2. Horizontal deflection - 5 nsec/cm
3. Rise time - less than 0.35 nsec
4. Input impedance - 50 ohms and high impedance probe (XI0 at
3.5 pF in parallel with 10 megohms) .

RDT C15-3 T
Page 15
4.5 .l. 2 Oscilloscope. Used to measure gain stability, integral
nonlinearity, output saturation level, and common-mode rejection. (Tektronix
541A with Type L plug-in or equal.)
1. Vertical sensitivity - 5 mV/cm
2. Horizontal deflection - 20 nsec/cm
3. Rise time - less than 10 nsec.
easure gain, rise
ode1 215A or
3. Output - positive
load
4. Output impedance
7. Pulse r
attenuator with 12 calibrated dB steps.
from 10 nsec to 100 nsec
le from 1.0 kHz to 1.0 MHz.
4. Output - positive or negative 1.0 volt into 50-ohm external load
5. Output impedance - 50 ohms.
4.5.1.5 Pulse Generator (tail pulse). Used to measure noise,
integral nonlinearity and output saturation level. (Tennelec TC800 or equal.)
1. Rise time - less than 20 nsec
2. Fall time - greater than 100 psec, RC tail
3. Pulse rate - 60 Hz.
4.5.1.6 Pulse Amplifier (CR-RC filtered). Used to measure noise
and noise immunity (ORTEC Model 410 or equal).
1. CR-RC filter - 0.10 psec and 0.5 psec 223% time constant
2. Gain - adjustable from 10 to 1000
3. Rise time (with no filter) - less than 60 nsec.

RDT C 15-3 T
Page 16
4.5.1.7 AC Voltmeter (true RMS). Used to measure noise.
(Ballentine Model 321 or equal.)
1. Range - 1.0 mV to 30 volts
2. Bandwidth - 5 Hz to 4 MHz with ~ 4 % accuracy.
4.5.1.8 Temperature Test Chamber. Used to gain stability
(Delta Design, Inc. Model 6545A oi equal.)
1. Range - 25°C to 70°C
2. Accuracy - 22°C.
4.5.1.9 Pulse Discriminator (intgg
stability. (ORTEC Model 406 or equal.)
rejection.
protection.
1. Threshold level- adj
turn precision poten
1. Output -)dsitive or negative 1000 volts.
Used to measure common-mode
to 1.0 volt rms across a 50-ohm load.
. Used to measure input
4.5.1.12 Power Supply, Low Voltage (two required). Used in all
tests to power preamplifier.
1. Output - positive or negative and adjustable from 12 volts
to 24 volts.
4.5.1.13 Attenuator. 20 dB. 50 ohm (four required). Used as
required. (Tektronix 011-059 or equal.)
1. Rise time - less than 0.5 nsec with less than 5% overshoot.
2. Power rating - 1/2 watt
4.5.1.14 Termination. 50 ohm (four requiredl. Used as required.
(Tektronix 011-049 or equal .)
4.5.2 Pulse Current Gain Test. Using the rectangular pulse gener-
ator at any convenient pulse rate and a pulse width of 100 nsec, apply a 0.5
mV pulse to the preamplifier input. For the 215A pulse generator, this will
require the 6 dB position of its attenuator switch and four external 20 dB
attenuators. Use RG 58/U to make the connection to the preamplifier input.
Connect the output of the preamplifier to the input terminal of the oscillo-
scope using RG 58/U cable and a 50-ohm termination at the oscilloscope. The
amplitude of the pulse observed out of the Type A preamplifier shall be 200 mV

RDT C 15-3T
Page 17
- +lo%. The current gain and polarities of input and output pulses are given
in Table 1.
Increase the input signal to 1.0 mV for the Type B preamplifier and
to 2.5 mV for the Type C preamplifier. The output of the Type B preamplifier
shall be 200 mV 50%. Each of the two outputs of the Type C preamplifier
shall be 250 mV 210% but of opposite polarity. The complete tests of the
Type B and Type C preamplifiers shall require gain measurements from each
input. Current gains and pulse polarities are also
3.2.13.
Repeat this test for the environmental c en in Section
4.5.3 Pulse ~ise'~ime Test. etup of 4.5.2. Adjust
and fall time of the output pulse. en the 10% and 90% points
rshoot on either edge
3.2.13.
ental conditions given in Section
amplifier input.) Connect
the output of t o the input terminal of the oscilloscope using
RG 58/U cable a nation at the oscilloscope.
e generator to give an output of 200 mV with the pulse
height potentiometer dial reading of 500 divisions (1000 divisions represent-
ing the full ten turns of this potentiometer). The undershoot following the
main pulse shall be ignored. The polarity of the main pulse shall be as given
in Table 1. Increase the input signal a precise factor of two by adjusting
the pulse height potentiometer to 1000 divisions. The output pulse shall in-
crease by a factor of two +lye based on a 400 mV reference. This measurement
requires a careful reading of the oscilloscope and using as much vertical de-
flection as is possible. (A more precise reading can be obtained by replacing
the oscilloscope with an amplifier and discriminator as per Sections 4.5.1.6
and 4.5.1.9 and using the oscilloscope to monitor the output of the discrim-
inator to ascertain the trigger levels.)
For a Type B preamplifier, two readings shall be required, one for
each input. For a Type C preamplifier, four readings shall be required, two
readings for each of two input signals.
4.5.5 Output Saturation Level. Repeat the test setup of Section
4.5.4. Adjust the pulse generator until there is strong evidence of satura-
tion in the preamplifier output signal. This output level shall not be less
than 600 mV.

Page 18
4.5.1 Output Pulse Undershoot. Repeat the test setup of Section
4.5.2 but at pulse rate not to exceed 10 kHz. Adjust the input pulse arrtpli-
tude until a 400 mV 210% is obtained. Using as much vertical gain on the
oscilloscope as possible, measure the undershoot following the main pulse.
This undershoot shall be less than 1% of the main pulse. All main pulse
polarities shall be as given in Table 1.
4.5.7 Pulse Rate Response. Repeat the
using the rectangular pulse generator with the
Adjust the pulse width to 50 nsec and the pulse
ators if needed) to give a 400 mV +lo% output pulse
from 10 kHz to 10
the output pulse.
4.5.8 Noise Test. Connect a 50-0%
preamplifier (both inputs for Type B and T
preamplifier to the input of the puls sing RG 58/U cable and a
50-ohm termination at the amplifier i the shaping time constants
of amplifier (CR-RC filter) to give a
time constant and an
voltmeter to the
(2 feet or less).
reading on the voltmeter.
Measure the he amplifier using the tail-type pulse
generator with at lea
c RC tail. The sinusoidal gain (AS) is 1.36
times the pulse gain. e sinusoidal gain may also be obtained with the sinewave
oscillator (Section .1.11) and the ac voltmeter by a measurement at
the center frequency of the CR-RC filter.
The noise current spectral density referred to the input can then be
obtained by
(AS) (RS) ~(B-w.)
where Eo is the ac voltmeter output (100 mV in this case) and ApA is the pre-
amplifier voltage gain (also equal to preamplifier current gain), B. W. is
the noise bandwidth of the amplifier filter (one MHz for CR-RC filter time
constant of 0.5 psec) and RS is the resistor value connected to the input.
(For filter time constants other than 0.5 psec, the B.W. can be calculated
from the expression B.W. = 1/27 where 7 is the filter time constant in
seconds.) The value obtained shall be less than 15 pA per Bz. The value
obtained for the Type B preamplifier and either output of e Type C preamp-
lifier shall be less than 30 pA per .
I,' Hz
4.5.9 Gain Stability Test. Place the preamplifier in the temperature
test chamber and apply suitable power supply voltages. Connect the pulse
generator to the input with RG 58/U cable. Adjust the pulse generator for
a LOO nsec pulse width, approximately a 10 kHz pulse rate and apply a 0.5 mV
pulse to the input. Connect the output to a pulse amplifier with 0.1 psec
CR-RC filtering. Use a 50-ohm termination at amplifier input.

RDT C 15-3 T
Page 19
Connect the output of the amplifier to the discriminator input with a short
length of RG 58/U cable.
Adjust the temperature control of the environmental chamber for 25°C
- +2OC and when stable adjust the gain of the amplifier until approximately a
5.0 volt pulse is obtained at its output. Adjust the discriminator level
scriminator.
nnected to the
ot spec if ied in
he half-trigger
point.) For a Type B preamplifier, two readi uired, one for
each input. For a Type C preamplifier, fo e required, two
readings for each of two input signals.
Raise the temperature to 60' abilize. Note
sing the dis-
, criminator readings at 25OC as alculate the percentage change
per OC. It shall be less than
o 25OC and allow the temperature to
stabilize. Adjust shold to obtain the half triggering
point. If this rea e than 20 mV(2.0 division of the discrimi-
nator dial) from th , the test should be repeated.
. Using the pulse generator at any con-
venient pulse r of 15 nsec, apply a negative 25 mV pulse
at the input to t escribed below. For the 215A pulse gen-
erator this wi ts attenuator switch and two, 20 dB fixed
attenuators. Mount both attenuators at the pulse generator and place a tee
connector on the output of the second attenuator. Use at least a 20-foot
section of RG 58/U cable to connect one port of the tee connector to the input
preamplifier. Connect a high impedance oscilloscope probe (XI0 attenuation)
to the other port of the tee connector. Any reflection from the preamplifier
can be observed trailing the main pulse approximately 20 to 30 nsec. These
reflections shall be less than +10% of the main pulse.
To obtain more signal for the oscilloscope, a resistive network as
shown in Fig. 3 can be used at the output of the second 20 dB attenuator.
A 50-ohm termination shall be substituted for the preamplifier input
impedance to confirm that there is no significant mismatch in the test set-
up*
4.5.11 Noise Immunity Test. Clamp the test fixture shown in Fig. 4
to the preamplifier housing. Connect the pulse generator to the fixture with
a RG 58/U cable. Apply a 100-nsec wide pulse, 5.0 volts in amplitude to the
test fixture. Use any convenient pulse rate. Connect the output of the pre-
amplifier to the input of a pulse amplifier which has a 50-ohm impedance and
a CR-RC filter with a 0.1 psec time constant. No output pulse from the main
amplifier should be observed above the normal level of output noise.

INC OR BN
TO PULSE GENERATOR
(THROUGH TWO, 50-OHM,
20 DB ATTENUATORS)
1
I
I
I
SMALL METAL ENCLOSURE
/
FIGURE 3
RESISTORS : 1% METAL
RESISTIVE NCTWO-RK FOR IKPUT IMPEDANCE TEST
1
TNC: OR BNC
TO OSCILLOSCOPE
TNC OR BNC
TO PREAMPLIFIER INPUT
50.OHM INPUT

FIGURE 4
50.OHM STRIP.LINE TEST FIXTURE FOR NOISE IMMUNITY TEST
RDT C 15-3T
Page 21
118 INCH EPCXY GLASS SHEET
7 REINFORCEMENT

RDT C 15-3T
Page 22
The test shall be repeated with the power supplies for the preampli-
fier turned off, but with all power leads connected, to confirm that there
is a negligible signal from other sources.
4.5.12 Input Protection Test. Connect the high voltage supply to
an RC circuit as shown in Fig. 5. The circuit should be mounted in a small
metal box with a connector as shown for connection to the preamplifier input.
Adjust the high voltage supply output to a
connect the circuit to the preampl'fier input with a sh
cable. Remove the connection to the reamplifier
input connector to ground. Repeat
tive 1000 volts. Test the preamplifier for curren Both
tests shall be normal.
of RG 58/U cables. In order to crea
cable, connect a 25-ohm resistor in
Use a small metal enclosure wit
onnectors together
ary to use one or two 50-ohm attenuators
give the required input to the preampli-
fier. Use an oscil a 5 mV/cm vertical deflection sensitivity to
because of the normal noise of the preamplifier. Estimate the peak-to-peak'
value of any sine-wave component by using the midpoint of the modulated "grass"
and convert this to an rms value. (Greater accuracy can be obtained if a
larger value for Ein can be used. This value can be increased until there is
evidence of limiting in the preamplifier .)
Calculate the commonmode rejection ratio (CMR) in decibels (dB) from
the following formula
CMR in dB = 20 loglO
E ~
in
E /A
out v
Av is the voltage gain and will be numerically equal to the differential current
gain as measured in Section 4.5.2 (nominally 400). The CMR shall be greater
than 40 dB for all frequencies.
4.6 Test Result Certification. A certified test report shall be made
for all tests and three copies submitted to the purchaser. A sample test
report form is shown in Appendix B.

TYPE N OR MHV
T 0
HIGH VOLTAGE
SUPPLY
/ SMALL METAL %w
L------------------------_]
----- - - A 7
RESISTORS !/2 W, 5R, ALLEN BRADLEY
FIGURE 5
R.C NETWORK FOR INPUT PROTECTION TEST.
RDT C 15-3T
TYPE N OR MHV

RDT C 15-3T
Page 24
4.7 Test Instrument Certification. A certified test instrument report
shall be made for all test instruments used in the testing of the preamplifiers
and three copes submitted to the purchaser. A sample test instrument form is
shown in Appendix C.
5. PREPARATION FOR DELIVERY
Supplier's name
Name and address of purchaser
Name of the preamplifier
Purchase order number.
6. NmES AM) ORDERING DATA
to the following:
tamination during
11 include, but not be limited
a) A quality assu n (Section 4.1.1)
b) Preliminar e preamplifier circuit (Section 4.2)
c) Preliminar mplifier enclosure and general
6.2 Ordering Data. The following technical and procurement data will
be furnished by the purchaser. If not furnished with the purchase document,
the supplier shall request any necessary data before submitting his bid.
Preamplifier Type. (Section 1.1)
Power Supply Voltages. (Section 3.3.3)
Filter Network Total Series Resistance.(Section 3.3.4)
Bias Supply and Fission Counter Connection. (Section 3.3.5)
Power Supply Connector. (Section 3.3.11)
Termination Resistor for Counter Bias Cable. (Section 3.3.13)
Hole for Input Signal Cable in Outer Box. (Section 3.4.1)
Hole for Input Signal Cable in Inner Box. (Section 3.4.2)
Hole for Output Signal Cable in Inner Box. (Section 3.4.3)
Hole for Power. Output Signal. and Counter Bias Cables in Outer Box.
(Section 3.4.4)'
Tests. (Section 4.5).

APPENDIX A
A. 1 RECOMMENDED CIRCUIT DESIGN FOR TH.E INPUT STAGE
RDT C 15-3 T
Page 25
A.l.l Circuit Description. A in Fig. Al.
It is shown with input circujt for the
input stage of the current pulse preamplifiers
same circuit could be used in ype C preamplifier.
This stage will give a current
of approximately 0.026Z/OC. e rise time of the output
pulse will be approximately 3

n~7--
oowo
-
0
RDT C 15-3T
Page 26

APPENDIX B
B.l TEST REPORT FORM FOR CURRENT PULSE PREAMPLIFIER
RDT C 15-3T
Page 27
Supplier Type No. Serial No.
Date Test Performed
RESULTS OF GAIN, RISE TURATION
LEVEL, UNDERSHOOT, PULSE RATE, AND
Type Input Output Gain Rise
Term- Term- Time Effect Non-lin- Stabili-
inal inal Normal earity t Y
A
B 1
B 2
C 1
C 1
C 2
(Yes o r No) % %I0C
RESULTS OF NOISE AND NOISE IMMUNITY TESTS
Type Output
Terminal
Noise
p~/d Hz
Induced Noise Less
Than Normal Noise Level
(Yes or No)

APPENDIX B (Continued)
RESULTS OF INPUT IMPEDANCE AND
INPUT PROTECTION TESTS
Type Input Reflect ion
Termina 1
A
Certified By: Date:
RDT C 15-3T
Page 28

C .1 TEST INSTRUMENT FORM
APPENDIX C
A. Oscilloscope (sampling): Manufacturer
Model No.
Date Last Calibration
Calibration Standards
B. Oscilloscope:
C.
Calibration Sta
RDT C 15-3 T
Page 29
D. : Manufacturer
E. : Manufacturer
Serial No.
Calibration Standards
F. Pulse Amplifier (CR-RC filtered): Manufacturer
Model No. Serial No.
Date Last Calibration -
Calibration Standards
G. AC Voltmeter (true RMS): Manufacturer
Model No. Serial No.
Date Last Calibration
Calibration Standards
H. Temperature Test Chamber: Manufacturer
Model No. Serial No.
Date Last Calibration
Calibration Standards

APPENDIX C (continued)
Pulse Discriminator (integral) : ?hnufac turer
Model No. Serial No.
Date Last Calibration
Calibration Standards
J. Oscillator (sine wavel: Manufacturer
Model No. Serial No.
Date Last Calibration
Calibration Standards
K. Others:
Model No.
Date Last Calibration
Calibration Standards
Date
RDT C 15-3 T
Page 30