ORTEC 113 Service manual

Model 113
Scintillation Preamplifier
Operating and Service Manual
Printed in U.S.A. ORTEC®Part No. 717560 1202
Manual Revision B

Advanced Measurement Technology, Inc.
a/k/a/ ORTEC®, a subsidiary of AMETEK®, Inc.
WARRANTY
ORTEC* warrants that the items will be delivered free from defects in material or workmanship. ORTEC makes
no other warranties, express or implied, and specifically NO WARRANTY OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR PURPOSE.
ORTEC’s exclusive liability is limited to repairing or replacing at ORTEC’s option, items found by ORTEC to
be defective in workmanship or materials within one year from the date of delivery. ORTEC’s liability on any
claim of any kind, including negligence, loss, or damages arising out of, connected with, or from the performance
or breach thereof, or from the manufacture, sale, delivery, resale, repair, or use of any item or services covered
by this agreement or purchase order, shall in no case exceed the price allocable to the item or service furnished
or any part thereof that gives rise to the claim. In the event ORTEC fails to manufacture or deliver items called
for in this agreement or purchaseorder, ORTEC’s exclusiveliabilityandbuyer’s exclusiveremedy shallbe release
of the buyer from the obligation to pay the purchase price. In no event shall ORTEC be liable for special or
consequential damages. Quality Control
Before being approved for shipment, each ORTEC instrument must pass a stringent set of quality control tests
designed to expose any flaws in materials or workmanship. Permanent records of these tests are maintained for
use in warranty repair and as a source of statistical information for design improvements.
Repair Service
If it becomes necessary to return this instrument for repair, it is essential that Customer Services be contacted in
advance of its return so that a Return Authorization Number can be assigned to the unit. Also, ORTEC must be
informed, either in writing, by telephone [[phone]] or by facsimile transmission [[phone]], of the
nature of the fault of the instrument being returned and of the model, serial, and revision ("Rev" on rear panel)
numbers. Failure to do so may cause unnecessary delays in getting the unit repaired. The ORTEC standard
procedure requires that instruments returned for repair pass the same quality control tests that are used for
new-production instruments. Instruments that are returned should be packed so that they will withstand normal
transit handling and must be shipped PREPAID via Air Parcel Post or United Parcel Service to the designated
ORTEC repair center. The address label and the package should include the Return Authorization Number
assigned. Instruments being returned that are damaged in transit due to inadequate packing will berepaired at the
sender's expense, and it will be the sender's responsibility to make claim with the shipper. Instruments not in
warranty should follow the same procedure and ORTEC will provide a quotation.
Damage in Transit
Shipments should be examined immediately upon receipt for evidenceof externalor concealeddamage. Thecarrier
making deliveryshouldbenotifiedimmediatelyofanysuchdamage, sincethecarrier is normallyliable for damage
in shipment. Packing materials, waybills, and other such documentation should be preserved in order to establish
claims. After such notification to the carrier, please notify ORTEC of the circumstances so that assistancecan be
provided in making damage claims and in providing replacement equipment, if necessary.
Copyright © 2002, Advanced Measurement Technology, Inc. All rights reserved.
*ORTEC®is a registered trademark of Advanced Measurement Technology, Inc. All other trademarks used
herein are the property of their respective owners.

iii
CONTENTS
WARRANTY ....................................................................... ii
SAFETY INSTRUCTIONS AND SYMBOLS ............................................... iv
SAFETY WARNINGS AND CLEANING INSTRUCTIONS ..................................... v
1. DESCRIPTION................................................................... 1
1.1. GENERAL ................................................................ 1
1.2. BASIC FUNCTION .......................................................... 1
2. SPECIFICATIONS ................................................................ 2
2.1. PERFORMANCE ........................................................... 2
2.2. CONTROLS ............................................................... 2
2.3. OUTPUTS ................................................................ 2
3. INSTALLATION .................................................................. 2
3.1. GENERAL ................................................................ 2
3.2. CONNECTIONTOPOWER................................................... 2
4. OPERATION .................................................................... 3
4.1. PANELCONTROLS......................................................... 3
4.2. INITIAL TESTING AND OBSERVATION OF PULSE WAVEFORMS .................... 3
4.3. CONNECTORDATA ........................................................ 3
4.4. TYPICALOPERATINGCONSIDERATIONS ...................................... 3
5. CIRCUIT DESCRIPTION ........................................................... 7
6. MAINTENANCE.................................................................. 7
6.1. TESTINGPERFORMANCEOFTHEPULSER..................................... 7
6.2. ADJUSTMENTOFDECAYTIMEOFOUTPUTPULSE .............................. 8
6.3. TABULATEDTESTPOINTVOLTAGES.......................................... 9
6.4. SUGGESTIONSFORTROUBLESHOOTING...................................... 9

iv
SAFETY INSTRUCTIONS AND SYMBOLS
This manual contains up to three levels of safety instructions that must be observed in order to avoid
personal injury and/or damage to equipment or other property. These are:
DANGER Indicates a hazard that could result in death or serious bodily harm if the safety instruction
is not observed.
WARNING Indicates a hazard that could result in bodily harm if the safety instruction is not observed.
CAUTION Indicates a hazard that could result in property damage if the safety instruction is not
observed.
Please read all safety instructions carefully and make sure you understand them fully before attempting to
use this product.
In addition, the following symbol may appear on the product:
ATTENTION–Refer to Manual
DANGER–High Voltage
Please read all safety instructions carefully and make sure you understand them fully before attempting to
use this product.

v
DANGER Opening the cover of this instrument is likely to expose dangerous voltages. Disconnect the
instrument from all voltage sources while it is being opened.
WARNING Using this instrument in a manner not specified by the manufacturer may impair the
protection provided by the instrument.
CAUTION To prevent moisture inside of the instrument during external cleaning, use only enough liquid
to dampen the cloth or applicator.
SAFETY WARNINGS AND CLEANING INSTRUCTIONS
Cleaning Instructions
To clean the instrument exterior:
! Unplug the instrument from the ac power supply.
! Remove loose dust on the outside of the instrument with a lint-free cloth.
! Remove remaining dirt with a lint-free cloth dampened in a general-purpose detergent and water
solution. Do not use abrasive cleaners.
! Allow the instrument to dry completely before reconnecting it to the power source.

vi

1
ORTEC MODEL 113
SCINTILLATION PREAMPLIFIER
1. DESCRIPTION
1.1. GENERAL
The ORTEC 113 Scintillation Preamplifier isanall-
transistor preamplifier designed for use with
photomultiplier tubes. It is a noninverting
preamplifier with no provisions for pulse shaping
except the variation of fall time. The 113 is
intended to operate into a shaping-type amplifier
suchas the ORTEC 410. A diode network prevents
destruction of the input transistor if a sudden
positive or negative high voltage is applied to the
input.
2. SPECIFICATIONS
PERFORMANCE
RISE TIME <60 nsec.
PREAMPLIFIER FALL TIME Fall time constant is
designed for 50
: sec, assuming a signal source
impedance of 1 M
S .
INTEGRAL NONLINEARITY
# 0.02%.
TEMPERATURECOEFFICIENT ±0.01%/°C,10to
50°C.
COUNTING RATE The gain shift of a 250-mV
referencepulse is<0.25% with the application of an
additional count rate of 65,000 counts/sec of 200-
mV random pulses.
CONTROL
INPUT CAP pF Switch selects desired input
capacity: 0, 100, 200, 500, 1000 pF.
INPUT
BNC connector; isolated for 1000 V; positive or
negative polarity, 1 M
S impedance shunted by 45
pF plus the capacity selected by switch S1 (0, 100,
200, 500, or 1000 pF).
OUTPUT
BNC connector; output impedance adjustablefrom
40 to 140
S . Output saturation level±10Vintoopen
circuit; ±5.1 V into 100
S load. Linear output ±7 V
into open circuit; ±3.5 V into 100
S load.
TEST PULSE
BNC connector; accepts a pulse generator output
with fast rise and slow decay to check operation of
the electronics; input impedance 100
S .
ELECTRICAL AND MECHANICAL
POWER REQUIRED +24 V dc, 17 mA;
! 24 V dc,
17 mA; supplied from any ORTEC transistor main
amplifier or an ORTEC Preamplifier Power Supply
through 10-ft captive cable.
WEIGHT (Shipping) 2.3 lb (1.05 kg).
WEIGHT (Net) 1.5 lb (0.68 kg).
DIMENSIONS 1.75 x 4 x 6 in. (4.5 x 10.2
x 15.3 cm).
RELATED EQUIPMENT
The 113 can be operated with anyORTEC Shaping
Main Amplifier. Test input pulses can be furnished
from any ORTEC Pulse Generator.

2
,
C
Q
V=
,
)(
sin
sin RRR RRR
R++ + =∠
∠
τ
3. INSTALLATION INSTRUCTIONS
3.1. CONNECTION TO
PHOTOMULTIPLIER TUBE
Connect the output of the photomultiplier to the
input of the 113 with a coaxial cable. This cable
should be kept as short as practicable. The
photomultiplier outputcanbetakenfrom the anode,
cathode, or any dynode and will generally be ac-
coupled. The input connector of the 113 is isolated
for 1000 V dc; however, it can be modified for
3000-V dc isolation by being replaced with a type
SHV connector.
3.2. CONNECTION TO A SHAPING MAIN
AMPLIFIER
The 113 can be used to drive long lengths of 93 S
cable to a shaping amplifier and is designed to be
directly compatible with ORTEC transistor main
amplifiers. The output impedance of the 113 is
93
S ; therefore if the 93 S cable is used, it is not
necessary to terminate it at the receiving end. If
unterminated cable is used on the output, with
impedance other than 93
S , resistor R24 should be
adjusted for an output impedance equal to the
value of the cable impedance to prevent pulse
reflections.
3.3. INPUT POWER
Power for the 113 is supplied through an Amphenol
connector (17-20090) on the rear of the chassis.
Power may be supplied by a single 45-V battery
with a tap at 22.5 V (use the tap as ground,
providing +22.5 V and
! 22.5 V; current drain is 17
mA)orbyanywell-filtered±24-Vpowersupplysuch
as the ORTEC 114 Preamplifier Power Supply.
If the 113 is used with ORTEC transistor main
amplifiers, power for the preamplifier can be
supplied from the main amplifier through the
interconnecting cable supplied with the 113.
3.4. TEST PULSE
A voltage pulse can be inserted at the Test Pulse
connector on the rear of the 113. The 113 has a
built-in charge terminator that converts the input
voltage to an input charge to simulate a charge
pulse from the photomultiplier tube. The shape of
the voltage test pulse should have a fast rise time
(less than 10-8 sec) followed by a slow expoential
decay back to the baseline (2 to 4 X 10-4 sec). A 1-V
input signal at the Test Pulse connector produces a
pulse of approximately 135 mV when an input
capacity of 100 pF is selected by S1.
4. OPERATING INSTRUCTIONS
The shape of the output pulse from the
photomultiplier tubeisdependent onthe form of the
light pulse, the transit-time spread in the
photomultiplier, and the anode resistance and
capacitance. Since the form of the light pulse and
the transit time of the tube cannot be altered, our
concern is with the anode and associated circuitry.
The signal at the anode appears as a current pulse
or a quantity of charge, and the voltage produced
by this quantity of charge is given by
where C = Cs+ Cin (see Fig. 4.1). (C1and C2are
coupling capacitors that are large in value
compared to C, and therefore accumulate a
negligible amount of voltage from the charge
transferred.) The voltage developed acrossCs+ Cin
will decay with a time constant of J
f= R J
C, where
and Rs= high-voltage supply output resistance.

3
Fig. 4.1. Functional Diagram of the 113 Preamplifier.
From the above equations it can be seen that the
pulse amplitude can be varied by varyingCin,which
can be varied by steps with switch S1 on the front
panel. The input capacity of the 113 is
approximately 45 pF plus the capacity selected by
S1. Rin was selected to produce afall time constant
of 50
: sec, assuming a driving source impedance
of 1 X 106
S . If a pole-zero-cancelled amplifier is
used followingthe 113, it will benecessary toadjust
the pole-zero trim on the amplifier each time a
different input capacitance is selected for the 113.
5. MAINTENANCE INSTRUCTIONS
5.1. TESTING PERFORMANCE
Insert a voltage pulse in the Input connector and
monitor the output withan oscilloscope. The output
pulse should be equal to the input pulse when the
output is not loaded and equal to one-half the input
pulse when it is loaded with 93
S and R16 plus R24
is equal to 93
S . Perform this test with both positive
and negative input pulses.
Insert a voltage pulse into the Test Pulse input
connector and monitor the output pulse with an
oscilloscope. For each volt input an output voltage
of approximately 135 mV should be obtained when
an input capacity of 100 pF is selected by S1. The
output pulse should decrease in amplitude as the
input capacity is increased.
5.2. SUGGESTIONS FOR
TROUBLESHOOTING
Perform the tests outlined in Section 5.1. If an
output pulse of the proper magnitude is not
obtained, check all dc voltages and compare them
with the values tabulated below.
5.3. DC VOLTAGES
The voltages listed below will help to locate
defective components. All voltages are measured
with respect to ground.
Typical dc Voltages
LOCATION DC VOLTAGES
+24 V Supply +24
- 24 V Supply - 24
Q1e - 1.0
Q1b - 0.5
Q1c +13.3
Q2e +13.8
Q2c - 1.65
Q3e - 13.2
Q3b - 12.6
5.4. 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 areused for a new
instrument. Always contact Customer Services at
ORTEC, [phone], 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 it reaches the
ORTEC factory.