Canberra 2012 User manual

اب
AMPLIFIER󰾰
)48 202 )4
COARSE GAIN
в 2
P/Z ADJUST
INPUT POLARITY
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SPECTROSCOPY AMPLIFIER
MODEL 2012
CONTENTS
Page
1 INTRODUCTION
1.1 General Description 14
1.2 Applications s m E 1-1
1.2.1 The NaK(TD) Life Time System КЕ НАВЕ 1-1
2 SPECIFICATIONS
2.1 ВИЕ окт пиша
22 Outputs 2...
2.3 Performance
24 Controls
25 Jumper Plugs 3
2.6 Connectors Types .
27 Power Requirements
2.8 Physical. гора 235%
3 CONTROLS AND CONNECTORS
3.1 Ganera «4 2 a east چم󰾯 ‚3-1
3:2 Front Panel 3-1
3.3 Rear Panel 23-2
4 OPERATING INSTRUCTIONS
General Брен иа heen на ва
Spectroscopy System Operation
System Setup
Performance Adjustments
Resolution Versus Count
Resend Shaping ума Ра AS Baws аф. 46
4.3 Resolution Destroying Interferences ........ 4-6
5 CHECKOUT AND MAINTENANCE/CALIBRATION
Equipment Required я
NIM ۷۵۱۵8۴۰۵۵ а зл موی مر󰾯 ise
Current Measurements .......
DC Level Checks and Adjustments .
Initial Setup) «vc vus
Amplifier DC Levels ........
Restorer Threshold DC Levels а
Amplifier perane Checks
Initial Setup —
Output
Pole Zero Adjustment
Coarse and Fine Gain Controls ........
O E TECHNOLOGIES
Р.О.
BOX
703,
118
RD.
51:
LA
MADERA,
NM
87539
[phone]

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е
ma o o o o o boit
SPECTROSCOPY AMPLIFIER
MODEL 2012
CONTENTS
(Continued)
Shaping Checks
Noise Measurement TET
Linearity Check .............
THEORY OF OPERATION
байа ون مه󰾯 kas aoe هه󰾯
Block Diagram Description ам уез
The Amplifier Section ...........
Circuit Description А
Gain Amplifiers . . . .
Input Amplifier Kl ...
Gain Amplifier K2
Integrator Amplifier AS ............
Amp Output Integrator
апе: DAVEE: Purse V rie Sa RG L
Restorer T

SPECTROSCOPY AMPLIFIER
MODEL 2012
Section 1
INTRODUCTION
1.1 GENERAL DESCRIPTION
The Model 2012 Spectroscopy Amplifier was designed using the latest integrated circuit technology to
insure a long lifetime of reliable and precise operation. The key to the performance of this instrument
is a cleverly designed baseline restorer which, because of its symmetrical characteristics, provides high
resolution for both Ge and HP Ge detectors. The reset pulses of the optical preamplifier of the HP Ge
detector are no problem to the Model 2012.
Although it is a high performance instrument. the Mode] 2012 is also very versatile. [t has al] the
characteristics necessary to make it useful with scintillation photomultipliers. gas proportional
counters, surface barrier detectors, high purity Ge and of course Ge(Li) detectors. High gain. low
noise, selectable time constants. and count rate optimization are several of the more important
features designed into the amplifier.
1.2 APPLICATIONS
This section is not intended as a complete survey of applications. It is intended to highlight the most
important features of the module and to indicate representative areas where they might be applied.
1.2.1 The Ма! СП) LIFE TIME SYSTEM
The Model 2012 amplifier is a versatile spectroscopy grade instrument capable of high count rate
restoration when used with a variety of detectors. Selectable shaping time constants of 0.5 and usec
for use with Nal( TD), Gas Proportional, Silicon Surface Barrier. Ge(Li), and high purity Germanium
detectors, are pushbutton selectable inside the unit.
To obtain excellent count rate performance from this amplifier does not require the adjustment of
variable restorer rates and thresholds. A symmetrical restorer automatically compensates for a wide
range of count rates. The gain range, temperature stability and non-linearity specifications enable the
2012 to be used in many applications requiring long counting times.
One application diagrammed in figure 1-1 shows the 2012 being used with four separate detector
systems. each utilizing the 2012 as the amplifier element, to provide their outputs to a mixer ‘router
which directs each to 1024 channels of MCA memory. The Ge(Li), and Gas Proportional detectors
utilize a 2usec shaping time constant while the Surface Barrier uses 0.5изес. The Nal Life Time System
uses the 20]2 Amplifier Unipolar output to time the occurrence of a gamma event from each detector.
The two timing SCA outputs are then translated by a TAC into a pulse spectrum proportional to the
time difference between the output signals.
© E TECHNOLOGIES
Р.О. BOX 703, 118 RD. 51€
LA MADERA, NM 87539
[phone]

DETECTOR РВЕАМР AMPLIFIER
2012
bec
Mixer/ Router МСА
ај 201
SE 2001 Уеб 3100-4K
7400 | 8220/4 Options - 01
-02
2013
CO bs 2006E вас
Proportional
Counter
2007P
Leading Edge
or
* Constant Fraction
Timing SCAs
es 2037
2007P اوت󰾯 e
Figure 1-1. Хай П) Life Time System

2.1 INPUTS
(SIGNAL) INPUT
2.2 OUTPUTS
UNIPOLAR OUTPUT
2:33 PERFORMANCE
GAIN RANGE
OPERATING TEMPERATURE
RANGE
GAIN DRIFT
DC LEVEL DRIFT
Section 2
SPECIFICATIONS
Accepts positive or negative linear pulses from an
associated preamplifier. Input BNC connectors
located on front and rear panels.
Amplitude: 0 to + 2 Volts for a linear output; + 12
Volt max.
Rise Time: Less than the shaping time constant
selected.
Decay Time Constant: 30useconds to ое
Input Impedance: Approximately 1K Ohms.
Provides positive-only linear pulses. BNC
connectors are located on the front and rear
panels. Short circuit protected.
Amplitude: + 10 Volts maximum.
Timing: Prompt.
Shaping: Active filter near-Gaussian shaped.
Coupling: DC restored.
Factory calibrated for 0 + 5mVDC.
Front Panel Zout: less than 1 ohm ог 93 ohms.
internally selectable.
Rear Panel Zout: 93 ohms
Continuously adjustable from X12 to Х1280.
product of the Coarse and Fine Gain Controls.
Coarse Gain Steps are: X4, X8. X16, X32, X64.
and X128.
Fine Gain Range covers: X3 to X10.
Oto + 50°C.
Less than + 0.0075%/0С of full scale.
Less than z 50۷ ۰

INTEGRAL NONLINEARITY
OVERLOAD RECOVERY
PULSE SHAPING
SHAPING TIME CONSTANTS
NOISE CONTRIBUTION
RESTORER
COUNT RATE PERFORMANCE
ЗРЕСТВОМ BROADENING
PEAK SHIFT
POWER SUPPLY SENSITIVITY
24 CONTROLS
COARSE GAIN
FINE GAIN
Less than + 0.05% of full scale linear output range.
Will recover to within = 2% of the full scale output
in 2 pulse widths for a x 1000 overload with the
pole/zero cancellation properly set.
Semi Gaussian shape: One differentiator, two
active integrators, and only one secondary time
constant (Approximately 50тзес); time to peak is
approximately 1.75 times the shaping time
constant.
O.Susec or 2usec unipolar shaping; internally
switch selectable.
With 2usec shaping time constant, less than 7шу
RMS referred to the input for any gain greater than
100.
Time variant (gated): on continuously.
Unipolar Output, 2usec shaping.
FWHM of a Соб0. 1.33MeV gamma peak for an
incoming count rate of 2kcps to 50ксрѕ and a 9
Volt pulse height will typically change less than
165.
The peak position of a CoO. 1.33MeV gamma
peak for an incoming count rate of 2kcps to
50kcps and а 9 Volt pulse height will shift less than
2 0.024%.
Supply AMP DC LEVEL
+ ۷ 10тУ 'Volt
- 24У 10mV/Volt
+12V 6mV/Volt
2 12V و󰾯
Supply
AMP
GAIN
+2۷ 0.028 ۶
-24V 0.028 ۶
*12V 0.011 %/Volt
42V 0.0022%/Volt
Front panel rotary switch, 32:1 range in six binary
steps.
Front panel ten turn precision potentiometer. X3
to XIO range, allowing maximum accuracy and
resetability.
t b

POLE/ZERO
INPUT POLARITY
TIME CONSTANTS
2.5 JUMPER PLUGS
Zout
2.6 CONNECTORS TYPES
INPUT
UNIPOLAR OUTPUT
TEST POINT
PREAMP POWER
2.7 POWER REQUIREMENTS
2.8 PHYSICAL
SIZE
NET WEIGHT
SHIPPING WEIGHT
Front panel twenty-two turn screwdriver
adjustment potenticmeter to optimize the
Amplifier baseline recovery and overload
performance for the preamplifier time constant
and main amplifier pulse shaping chosen; range
30usec to ге preamp decay time constant
Front pane! toggle switch, * (positive), - (negative)
positions; only affects signal INPUT connector.
Internal push button switch to select shaping time
constant of 0.5 or 2.Орзес
2 position jumper plug that selects the front panel
UNIPOLAR OUTPUT impedance of less than 1
ohm or approximately 93 ohms. Shipped in the
low impedance position.
Front and rear panel. BNC.
Front and rear panel. BNC.
Unipolar Output. front panel, Selectro - SKT-41
Rear panel, Amphenol #17-10090.
+24УрС - 45۳۸
- 24۷17 - 50тА
+12VDC - 40mA
-12VDC - 30mA
Standard single-width NIM module 1.35 x 8.71
inches (3.43 x 22.13 CM) per TID 20893 (rev.).
2.2 Ibs. (1.0 kgs.)
4.0 Ibs. (1.8 kgs.)
y

Section 3
CONTROLS AND CONNFCTORS
3.1 GENERAL
Complete understanding of the purpose of the various controls and connectors is essential for the
proper operation of the Model 2012 and it is recommended that this section be read before proceeding
with the operation of the module.
3.2 FRONT PANEL (See Figure 3-1)
COARSE GAIN
Six position rotary switch selects
gain factors of X4, ХВ, X16, X32,
‘X64 and X128; multiplied by the
FINE GAIN control settings.
FINE GAIN
Ten turn precision potentiometer
selects variable gain factor from
X3 to X10. Resetability within
£0.03%.
POLE ZERO-
22 turn screwdriver adjust
potentiometer to compensate for
the undershoot caused by the
preamplifier fall time constant
Adjustable for preamplifier fall
time range of З0увес. to оо.
INPUT POLARITY
Toggle switch to set the Model
2012 for the polarity of the
incoming preamplifier signal.
UNIPOLAR OUTPUT
Provides a positive semi-gaussian
Output pulse; active filter pulse
shaping, Look under Section 2.2
for signal specifications. Test
point is provided, tes point
‘output impedance is 470 ohms.
INPUT:
Accepts positive or negative linear
pulses from asiociated
preamplifier. Signal requirements
are: Amplitude 0 to +12 volts
^ maximum; Rise time less than
shaping time constant; Decay
time constant 30sec 10 соў
approximately 1K ohms.
Figure 3-1. Front Panel Controls and Connectors
3-1

3.3 REAR PANEL (See Figure 3-2)
INPUT.
Additional input wired in parallel
with the front panel signal INPUT
BNC connector.
UNIPOLAR OUTPUT
Signal specifications are identical
to the front panel output except
for 93 ohm series - connected
PREAMP POWER output impedance. Use this rear
Provides power for any Canberra panei output when driving long
preamplifier; Model 1708 lengths of interconnecting coaxial
Preamplifier requires a special cable to prevent distorting the
cable. linear signal (oscillations).
PIN FUNCTION
1 Ground
2 Clean Ground.
4 +12VDC
6 - MVDC
1 +24VDC
E -12мрс а MODULE POWER
Connector accepts operating
voltages from an AEC Standard
NIM bin/power supply such as the
Canberra Model 2000.
FUNCTION
16 +12VDC
17 -12VDC
28 *24VDC
29 -замос
34 Ground
42 ‘Clean Ground
Figure 3-2. Rear Panel Controls and Connectors.
3-2

—
Zout
90
куз @
—À
ROUEN, NEMINEM EMI
Figure 3-3. Internal Controls, Left Side Cover Removed.

Section 4
OPERATING INSTRUCTIONS
4.1 GENERAL
The purpose of this section is to familiarize the user with the operation of the Model 2012 Amplifier
and to check that the unit is functioning correctly. Since it is difficult to determine the exact system
configuration in which the module will be used, explicit operating instructions cannot be given.
However, if the following procedures are carried out, the user will gain sufficient familiarity with this
instrument to permit its proper use in the system at hand.
4.2 SPECTROSCOPY SYSTEM OPERATION
The following instructions apply to obtaining the maximum performance capabilities of the Model
2012 depending on operating and system needs.
4.2.1 SYSTEM SETUP
A block diagram of a typical Canberra gamma spectroscopy system is shown in Figure 4-1.
سح
60
е 2229 8100󰾰
Ge(Li)󰾰
"m Detector MP󰾰
source󰾰
Figure 4-1. Typical Gamma Spectroscopy System.
1. INTERNAL JUMPER PLUGS
Prior to installation and set up the internal jumper plug should be set to its desired
positions. See Figure 3-3.
For the Spectroscopy Amplifier there is the Zoy jumper plug which controls the output
impedance of the front panel (only) UNIPOLAR OUTPUT. The output impedance can be
changed from 0 ohms to 93 ohms. The rear panel output has a fixed output impedance of.
93 ohms, series connected.
When using the front panel low impedance output. short lengths of interconnecting coaxial
cable need not be terminated. To prevent possible oscillations, longer cable lengths should
be terminated at the receiving end in a resistive load equal to the cable impedance (93 ohms
for type RG-62/U cable).
The rear panel 93 ohms output may be safely used with RG-62/U cable up to a few hundred
feet. However, the 93 ohm impedance is in series with the load impedance, and a decrease in
the total signal range may occur. For example, a 50% loss will result if the load impedance is
93 ohms.
41

ө
Insert the 2012 into а standard ММ BIN. Preamp power is provided by means of a
connector located on the rear panel of the 2012 amplifier. Allow the total system to warm
up and stabilize.
Set the 2012 controls as indicated below:
a. Shaping: 2 microseconds (Internal)
COARSE GAIN: 16
FINE GAIN: 2.2
This
will
give
approximately
а
9
volt
output
when
using
a
preamp
gain
of
100m
V/MeV
and
а
Соб0
radioactive
source.
b. Set the INPUT POLARITY switch to match the output polarity of the preamp
Install a "Tee" Connector on the 2012 Amp Output. Connect one end to the ADC Input on
the analyzer. The ADC must be direct coupled for linear input signals to fully exploit the
count rate capabilities of the Mode! 2012 amplifier. All Canberra ADC's are DC coupled.
Connect the second end of the “Tee” Connector to an oscilloscope and monitor the AMP
OUTPUT.
4.2.2 PERFORMANCE ADJUSTMENTS
а. The Pole/Zero is extremely critical for good high count rate resolution. See note 1 on page
4-4. Adjust the radiation source count rate between 2kcps and 25kcps. While observing the
AMP OUTPUT on the scope, adjust the Роіе/2его so that the trailing edge of the Gaussian
pulse returns to the baseline with no over or under shoots. Figure 4-2a shows the correct
setting of the Pole/Zero control, with Figures 4-2b and 4-2с showing under and over
compensation
for
the
preamplifier
decay
time
constant.
Notice
some
small
amplitude
signals
with long decay times in Figure 4-2a. These are due to charge trapping in the detector and
cannot be corrected by the Pole/Zero control.
Pole Zero adjustment using a square wave and preamp test input. See Note 2 on page 4-4.
Driving the preamp test input with a square wave. will allow a more precise adjustment of
the amplifier P/Z.
1. The Amplifiers controls should be basically set for its intended application: coarse
gain, shaping, input polarity.
Adjust the square wave generator for a frequency of approximately 2kHz.
3. Connect the Function Generator's output to the Preamp's Test Input.
4. Remove all radicactive sources from and near the detector.
5. Set the scope's Chan. 1 vertical sensitivity to 5 Volts/Div., and adjust the main time
base to O.Imsec/Div. Monitor the 20125 UNIPOLAR OUTPUT and adjust the
function Generator's amplitude control (attenuator) for output signals of + 8 volts.
Note: Both positive and negative Gaussian pulses will be observed at the output

Figure 4-2a
Correct P/Z Compensation.
Figure 4-2b
Undercompensated P/Z
Figure 4-2c
Overcompensated P/Z
Oscilloscope
Vert: SOmV/Div
Horz: 10usec/Div
Source Соб0
1.33meV Peak: 7۷ Amplitude
Count Rate: Approx. 3 kcps
Shaping: usec
Figure 4-2. Pole/Zero adjustment with a Live source (Co50)
43

&
6. Reduce the Scope vertical sensitivity to 5ümV/Div. See Note ۱ below
Figure 4-32 shows the correct setting of the P/Z control. Figures 4-3b and 4-3c show
under and over compensation for the preamplifier decay time constant
As illustrated in Figure 4-3a. the UNIPOLAR OUTPUT signal should have a clean
return to the baseline with no bumps. overshoots or undershoots
HPGe detectors and Si Systems with Optical Feedback Preamps.
For normal Si systems the P/Z is usually set at го , fui] counter clockwise. However. on some
systems the P/Z may need to be slightly tweaked for optimum overload recovery to the
preamp's reset pulse.
NOTE 1
At high count rates the P/Z adjustment is extremely critical for maintaining good resolution
and low peak shift. For a precise and optimum setting of the P/Z a scope vertical sensitivity
of 5OmV/Div should be used. Higher scope sensitivities can also be used, but result in a less
precise
P/Z
adjustment.
However.
scopes
such
as
the
Tektronix
Models
453,
454,
475
and
476 will overload for a 10 volt input signal when the vertical sensitivity is set for SOmV/Div
Overloading the scope inpur will distort the signal's recovery to the baseline. Thus the P/Z
will be incorrectly adjusted resuiting in a loss of resolution at high count rates. To prevent
overloading the scope a clamping circuit, such as the one illustrated in Figure 4-4, can be
used at the scope input.
Ik
Атршіег
Sec
m 9 "m 9 т
HP2800-2835 T
Schottky diodes
Figure 4-4. Scope Input Clamp.
МОТЕ 2:
When adjusting the P/Z using the square wave technique, Ше calibration square wave
generated by the oscilloscope can be used. Most scopes generate а 1kHz square wave used to
calibrate the vertical gain and probe compensation. Connect the scope CALIBRATION
Output thru an attenuator to the preamp test Input and repeat 4.2.2b steps 1 thru 6.
AMP DC LEVEL
The AMP OUTPUT dc level is factory calibrated to + 1 millivolt. The adjustment is made
internally Бу ВУЗ and covers a range of + 100 millivolt. See the checkout and maintenance
section for further information.

Figure 4-3a
Correct P/Z Compensation
Figure 436
Undercompensated P/Z
Figure 4c
\ Overcompensated P/Z
Oscilloscope
Vert: 50mV/Div
Horz: 0.2usec/Div
Figure 4-3. Pole/Zero Adjustment using square wave pulse and preamp test input

ё
МСА CONTROLS
To get optimum resolution, the Lower Level Discriminator on the АРС should be se: just
above the noise so that the effects of pile-up are minimized
4.2.3 RESOLUTION VERSUS COUNT RATE AND SHAPING
The 2usec shaping time constant is optimum for Ge(Li) detector systems over a wide range of
incoming count rates. For high resolution larger shaping time constants offer a better signal to noise
(S/N) ratio, resulting in better resolution. However as the count rate increases, the effects of piie up
will degrade the resolution much sooner. The optimum shaping time constant depends on the detector
(such as its size, configuration and collection characteristics), preamplifier and incoming count rate.
Below is a list of optimum shaping time constants for some other common detectors
Detector Optimum Shaping (usec)
Scintillation Photomultiplier 05
Gas Proportional Counters 0.5 or 2
Silicon Surface-Barrier 0.5 or 2
Cooled Silicon 80r12
The Model 2012 is normally factory set for 0.5иѕес or 2usec shaping time constants. However the
shaping time constants can be changed to 8 and l2usec to be compatible with cooled Silicon
detectors. Change the components as follows:
مد ما چم бои󰾰
Change СІ from 560۳1 to 00۲
Change C2 from 1600pf to 560рЕ
Change R1 from 19.1K ohms to 22.6K ohms
Change R2 from 52.3K ohms to 11K ohms
Change C3 from 130pf to 2000pf
Change C4 from 360pf to 1300pf
Change C5 from 200pf to 2400pf
Change Сб from 5۱0۲۲ to 1600рЕ
Change C25 from 47pf го ۲
Change C26 from 200р to 510pf
All resistors are RN60C’s and capacitors are 1% silver mica.
43 RESOLUTION DESTROYING INTERFERENCES
а. Vibration transmitted to the detector and cryostat. This can be through the floor or
mounting, as well as direct audio coupling through the air. Vibration isolators in the
mounting and sound absorbing covers around the detector can reduce this problem.
The close proximity of a radio station can be picked up by the “dipstick” of the cryostat.
Good contact between the dipstick and the cryostat can often help solve this problem
Beware of grounding the cryostat and dipstick as this may increase power line frequency (50
or 60 cycle) ground loops.
Ground Loops. Power line frequency interference can be caused by long cable connections
between the detector, preamplifier and shaping amplifier. There is no general solution for
this problem. As a first step, the preamp should use the power supplied by the main shaping
amplifier. Second, the system should have a single point house ground. For example. on a
general system connect the NIM Bin to house ground via the third prong on the AC Line
Cord. Isolate all other equipment requiring AC Voltage from the house ground. Connect all
the chassis in the system to the grounded NIM Bin using heavy braided wire.

High voltage power supplies. Generally, the H.V.P.S. should float from power line ground
with the only ground being made at the preamplifier through the high voltage connecting
cable.
Analyzer EMI. И the detector is located within 10 to 15 feet of a multichannel analvzer
containing a ferrite core memory. It can receive EMI (electro-magnetic interference). This is
due to high memory core currents during the memory cycle of the analyzer. The only
practical cure for this problem is to operate the analyzer in the “Live” Mode of
accumulation. In this way, the memory cycle only operates while no signal is being
analyzed.
Is the output of the spectroscopy amplifier and the input of the ADC fully compatible? This
may seem an obvious consideration, but it is commonly overlooked. The shaping time
constant as stated on the spectroscopy amplifier is no: the rise time of its output signal. In
the case of a Model 2012 Amplifier, the time-to-peak of the AMP OUTPUT is 1.75X the
shaping time constant. Therefore, а 12рѕес shaped pulse requires 2lusec to reach full
amplitude. Many analyzers will not handle this: instead of analyzing the peak of the signal.
they analyze a percentage of the rise time.
Amplifier parasitic oscillations. If the cable connecting the front panel outputs of the
amplifier to the ADC exceed 10 to 20 feet in length, oscillations can occur. The cure is to
use RG-62/U cable (93 ohm impedance) and terminate the ADC end of the cable with a
93.1 ohm metal film resistor. Alternatively, the 93 ohm output impedance of the amplifier
can be used with no terminator.
47

Section 5
CHECKOUT AND MAINTENANCE/CALIBRATION
5.1 EQUIPMENT REQUIRED
в.
Oscilloscope (Tektronix Models 453, 465, 581 or equivalent)
Digital Voltmeter )> 0.1% Full Scale Accuracy)
Resistive Voltmeter Probe (200 to 1 K ohms in series)
Current Meters
Noise Meter (Model HP-400H or equivalent)
Pulser - Model 1407 (either standard or modified for 20V Out)
NIM Power Supply
5.2 NIM VOLTAGE CHECK
With a DVM, measure the NIM Power Supply voltages and adjust if they are outside of the following
ranges:
+24У:
-24У:
*12V:
-12V:
323.98 to
-23.98 to
*11.99 0
-11.99 to
5.3 CURRENT MEASUREMENTS
a.
b.
Apply power to the Model 2012 and measure the currents. They should be within the
following ranges:
+24V
+12V
-12V
-24V
NOTE:
35 to 55mA
30 to 50mA
20 to 40mA
40 to 60mA
A greater deviation in currents indicates a faulty unit. Gross errors would probably
be due to faulty or reversed capacitors. shorted or open transistors, etc.
Replace the current meters with a power cable.
5.4 DC LEVEL CHECKS AND ADJUSTMENTS
5.4.1 INITIAL SETUP
a.
b.
Set the Model 2012 COARSE GAIN to 4.
Connect a 93 or 100 ohm terminator to the rear panel INPUT.
5.4.2 AMPLIFIER DC LEVELS
a.
Measure the level at TP4: It should measure - 150 to + 150mVDC.

b. Monitor TPI and adjust КУЗ for- 1 to + ImVDC.
5.4.3 RESTORER THRESHOLD DC LEVELS
a. Measure the levels at the following points.
A2 pin 3: -80 ۱۵ - ۷
A2 pin 2: Ото - ۷
b. Measure the level at A2 pin 6 versus COARSE GAIN. The level should be be within the
range indicated below:
COARSE GAIN A2 Pin 6
4,8 - 140 ۱0+ ۷
16,32 -120to* 30mV
64 -100to* ۷
128 -50 to+ ۷
5.5 AMPLIFIER OPERATIONAL CHECKS
5.5.1 INITIAL SETUP
a. Set the controls as follows:
Model 2012 Controls
COARSE GAIN 4
FINE GAIN: 10
SHAPING: 2usec. (internal)
POLE ZERO: Fully CCW
INPUT POLARITY: POS
Model 1407 Controls
PULSE HEIGHT: 5.4 (2.7 if modified 1407)
NORMALIZE 10
POS/NEG: POS
60Hz/OFF/90Hz: 90Hz
RISE TIME: MIN
FALL TIME: 400изес.
ATTENUATION: x10
b. Connect a 93 or 100 ohm terminator to the 201? rear panel INPUT.
c. Connect the Model 1407 ATTEN OUTPUT to the 2012 front panel INPUT with RG-62
coax cable.
d. Connect the Model 1407 NORMAL OUTPUT to the EXT TRIG input of the scope. Set the
scope triggering to EXT, +.
5-2