Pyramid CR10 User manual

CR10
Combined Charge-sensitive Pre-amplifier
and Shaping Amplifier
User Manual
Pyramid Technical Consultants, Inc.
1050 Waltham Street Suite 200, Lexington MA 02421 USA
US: TEL: [phone]  FAX: [phone]  EMAIL:
[email protected]
Europe: TEL: [phone]

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1 Contents
1 Contents .............................................................................................................................................................. 2
2 Table of Figures .................................................................................................................................................. 5
3 Safety Information ............................................................................................................................................. 6
4 Models ................................................................................................................................................................. 8
5 Scope of Supply .................................................................................................................................................. 9
6 Optional Items .................................................................................................................................................. 10
6.1 Power supplies .............................................................................................................................................. 10
6.2 Cables and adaptors...................................................................................................................................... 10
6.3 DIN rail mount .............................................................................................................................................. 10
7 Intended Use and Key Features ...................................................................................................................... 11
7.1 Intended Use .................................................................................................................................................. 11
7.2 Key Features ................................................................................................................................................. 11
8 Specification ...................................................................................................................................................... 12
9 Installation ........................................................................................................................................................ 17
9.1 Mounting ....................................................................................................................................................... 17
9.2 Grounding and power supply ........................................................................................................................ 18
9.3 Connection to equipment ............................................................................................................................... 18
9.3.1 Making connections ............................................................................................................................. 18
9.3.2 Typical setup ........................................................................................................................................ 18
9.3.3 Cables .................................................................................................................................................. 19
10 Circuit overview ............................................................................................................................................... 21
11 Setup and Calibration ...................................................................................................................................... 23

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11.1 Gain setting .............................................................................................................................................. 23
11.2 Pole-zero setting ....................................................................................................................................... 23
11.3 Offset correction ....................................................................................................................................... 24
11.4 Charge and energy calibration................................................................................................................. 24
12 Using the Test Input ......................................................................................................................................... 26
13 Connectors ........................................................................................................................................................ 27
13.1 Front panel connectors ............................................................................................................................. 27
13.1.1 Bias in ............................................................................................................................................. 27
13.1.2 Detector ........................................................................................................................................... 27
13.1.3 Test.................................................................................................................................................. 27
13.2 Rear panel connectors .............................................................................................................................. 27
13.2.1 Output ............................................................................................................................................. 28
13.2.2 Power .............................................................................................................................................. 28
14 Controls and Indicators ................................................................................................................................... 29
14.1 Front panel controls ................................................................................................................................. 29
14.2 Rear panel controls and indicators .......................................................................................................... 29
14.2.1 Offset ............................................................................................................................................... 29
14.2.2 Pole-zero ......................................................................................................................................... 29
14.2.3 Fine gain .......................................................................................................................................... 29
14.3 Front panel indicators .............................................................................................................................. 29
14.4 Rear panel indicators ............................................................................................................................... 29
14.5 Internal settings ........................................................................................................................................ 30
14.5.1 Handling precautions ...................................................................................................................... 30
14.5.2 Accessing internal components ....................................................................................................... 30
14.5.3 Cremat modules .............................................................................................................................. 31
14.5.4 Jumpers ........................................................................................................................................... 31
15 Fault-finding ..................................................................................................................................................... 33
16 Maintenance ..................................................................................................................................................... 35
17 Returns procedure ........................................................................................................................................... 36

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18 Support .............................................................................................................................................................. 37
19 Disposal ............................................................................................................................................................. 38
20 Declaration of Conformity .............................................................................................................................. 39
21 Revision History ............................................................................................................................................... 40

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2 Table of Figures
Figure 1. CR10 chassis end panels (SHV connectors). Dimensions mm. ................................................................. 14
Figure 2. CR10 case plan and side views (SHV connectors). Dimensions mm. ........................................................ 15
Figure 3. CR10 case (BNC signal connector option) end panel and plan view. Dimensions mm.............................. 16
Figure 4. DIN rail mounting. ...................................................................................................................................... 17
Figure 5. Schematic CR10 installation for readout of a proportional chamber ........................................................... 19
Figure 6. Effect of cable capacitive load on noise ...................................................................................................... 20
Figure 7. CR10 block schematic. ................................................................................................................................ 21
Figure 8. Signals at A (2 mV, 200 nsec / div), B (100 mV, 50 µsec / div), C (1 V, 5 µsec / div) .............................. 21
Figure 9. Incorrect pole-zero setting (top), correct pole-zero setting (bottom) ........................................................... 24
Figure 10. Measured pulse height spectrum for Am-241 gamma line, CR-110 and 1 µsec shaping ........................... 25
Figure 11. Determination of gamma energy by scaling .............................................................................................. 25
Figure 12. Effect of voltage square wave (red) injected into test input....................................................................... 26
Figure 13. Injecting tail pulses to achieve a unipolar response to the test input ......................................................... 26
Figure 14. Front panel connectors .............................................................................................................................. 27
Figure 15. Rear panel connectors ............................................................................................................................... 27
Figure 16. Rear panel controls and indicators............................................................................................................. 29
Figure 17. Location of internal switches and jumpers. ............................................................................................... 31

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3 Safety Information
This unit is designed for compliance with harmonized electrical safety standard EN61010-
1:2000. It must be used in accordance with its specifications and operating instructions.
Operators of the unit are expected to be qualified personnel who are aware of electrical safety
issues. The customer’s Responsible Body, as defined in the standard, must ensure that operators
are provided with the appropriate equipment and training.
The unit is designed to make measurements in Measurement Category I as defined in the
standard.
Although the CR10 does not generate dangerous voltages, nor is it designed to measure directly
such voltages, it may be supplied with high voltage bias up to +/- 3kV from an external supply.
This voltage is then present inside the case. Appropriate precautions must be taken.
The unit must not be operated unless correctly assembled in its case. Only Service Personnel, as
defined in EN61010-1, should attempt to work on the disassembled unit, and then only under
specific instruction from Pyramid Technical Consultants, Inc. or their authorized distributors.
The unit is designed to operate from +/- 12 VDC power rails, with a maximum current
requirement of 50mA on each rail. Up to four CR10s can be powered and provided with high
voltage bias by one C400 pulse counting detector controller.
The unit must be grounded by secure connection to a grounded conducting surface. If the unit is
mounted on an insulating surface, then one of the four mounting screws must be re-assigned as a
grounding connection.
Some of the following symbols may be displayed on the unit, and have the indicated meanings.

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Direct current
Earth (ground) terminal
Protective conductor terminal
Frame or chassis terminal
Equipotentiality
Supply ON
Supply OFF
CAUTION – RISK OF ELECTRIC SHOCK
CAUTION – RISK OF DANGER – REFER TO MANUAL

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4 Models
CR10 Combined charge-sensitive pre-amplifier and shaping amplifier.
Configuration selections
-GN Input stage conversion gain selection:
N=0 1400 mV pC-1 (CR-110)
N=1 130 mV pC-1 (CR-111)
N=2 13 mV pC-1 (CR-112)
-TN Shaping amplifier stage time constant selection:
N=1 100 ns (CR-200-100ns)
N=2 250 ns (CR-200-250ns)
N=3 500 ns (CR-200-500ns)
N=4 1000 ns (CR-200-1µs)
N=5 2000 ns (CR-200-2µs)
N=6 4000 ns (CR-200-4µs)
-BR Baseline restorer option (recommended for high count rate applications)
-BNC BNC signal input and bias input connectors option (default is SHV)
The following options are adjustable in the field by trained service personnel by internal jumper
settings.
-N/P Negative or positive input signal polarity selection (default is positive)
-IG1/10/100 Intermediate stage gain selection x1, x10, x100 (default is x10)
Example
CR10-G1-T2-BR-N-IG1 CR10 configured with 130 mV pC-1 pre-amp conversion gain, 250
nsec shaping time constant, baseline restorer module, negative input pulse polarity and x1
intermediate stage gain. No connector type option was stated, so the unit will have SHV
connectors as the default.

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5 Scope of Supply
CR10 model as specified in your order.
USB memory stick containing:
Data sheet
User manual
Test results
Optional items as specified in your order.
OEM customers may not receive all the items listed.

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6 Optional Items
6.1 Power supplies
PSU-B12. +24 VDC to +/-12 VDC power supply, input for 2.1mm threaded jack, output 9 pin
DSub female.
Note: If the CR10 is used with a C400, +/-12V power is provided by the C400.
6.2 Cables and adaptors
CAB-SHV-2-SHV HV cable assembly, 2’ (0.6 m). For signal input and HV bias input.
CAB-SHV-3-SHV HV cable assembly, 3’ (0.9 m). For signal input and HV bias input.
CAB-BNC-COLN2-NC Coax cable assembly low noise, 2’ (0.6 m). For signal input (BNC
connector option).
CAB-BNC-COLN3-NC Coax cable assembly low noise, 3’ (0.9 m). For signal input (BNC
connector option).
CAB-SHV-10-SHV HV cable assembly, 10’ (3 m). For bias voltage input.
CAB-L00-10-L00 Lemo 00 coax cable assembly, 10’ (3 m). For test pulse input and signal
output.
CAB-L00-30-L00 Lemo 00 coax cable assembly, 30’ (9 m). For test pulse input and signal
output.
CAB-L304M-10-D9M Power cable assembly, 10’ (3 m). To power CR10 from PSU-B12 or
C400.
CAB-L304M-30-D9M Power cable assembly, 30’ (9 m). To power CR10 from PSU-B12 or
C400.
ADAP-LEMO-BNC Adaptor, Lemo 00 coax plug to BNC jack. For test pulse input and signal
output if using BNC-terminated cables.
Other lengths available on request.
6.3 DIN rail mount
MTG-DIN35-11462. Mounting adaptor for 35mm standard DIN rail. CR10 can be mounted
along or across the rail.

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7 Intended Use and Key Features
7.1 Intended Use
The CR10 is intended to amplify and condition small charge pulses generated in radiation
detectors such as diodes and proportional counters. With suitable gain configuration it can also
handle larger pulses from detectors such as Geiger counters, photomultipliers and channel
electron multipliers. It is intended for use in moderate count rate applications where the amount
of charge in each pulse must be measured, for example by an multi-channel analyser, or where
the pulse must be counted by a discriminator/counter such as the C400.
The CR10 may be used to readout detectors that require bias voltage, either applied to the signal
readout electrode or another electrode. Bias to the signal readout electrode is connected from the
bias input internally in the CR10, and must be limited to +/- 3 kV which is the rating of the
decoupling capacitors.
The -BR option adds a baseline restorer module which is recommended for applications where
the average count rate can exceed about 10 kHz, especially if accurate pulse height analysis is the
objective.
The CR10 has design features which make it tolerant of electrically noisy environments, but the
place of use is otherwise assumed to be clean and sheltered, for example a laboratory or light
industrial environment. Users are assumed to be experienced in the general use of precision
electronic circuits for sensitive measurements, and to be aware of the dangers that can arise in
high-voltage circuits.
7.2 Key Features
Single compact unit containing AC-coupling and bias network, charge-sensitive pre-amplifier,
intermediate gain stages, shaping amplifier, optional baseline restorer and line driver output.
Gaussian output pulse shape for optimum pulse height measurement.
Uses proven amplifier modules from Cremat, Inc..
Multiple build configurations available to suit many radiation detector types.
Built-in high voltage bias network rated up to +/- 3 kV.
Configurable for positive or negative input charge pulses.
SHV or BNC detector and bias input connections.
Test pulse input.
Adjustable gain.
Optional baseline restoration module for higher rate applications.
Compatible with Pyramid C400 pulse counting detector controller.

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8 Specification
Overall
Cremat modules fitted One of CR110, CR111 or CR112 preamplifier
One CR200 shaping amplifier with either 100 nsec, 250 nsec, 500
nsec, 1 µsec, 2 µsec, or 4 µsec shaping time constant
One CR210 baseline restorer (optional)
Example overall gain 2.5 V pC
-1
into 50 ohms (-G1-T2-IG10 configuration, fine gain
50% setting).
Example noise Unloaded: < 0.5 mV RMS, < 3.5 mV peak to peak into 50 ohms
DC (-G1-T2-IG10 configuration fine gain 50% setting) to 5 MHz.
Noise increases with capacitive load on input.
Equivalent noise charge < 0.3 fC RMS
Charge-sensitive input stage
Conversion gain (nominal) -G0 (CR-110) 1.4 V pC
-1
-G1 (CR-111) 0.13 V pC
-1
-G2 (CR-112) 0.013 V pC
-1
Rise and decay time (zero
input capacitance load)
-G0 (CR-110) 3 nsec / 140 µsec
-G1 (CR-111) 2 nsec / 150 µsec
-G2 (CR-112) 3 nsec / 50 µsec
AC coupling 10 nF 3 Kv series capacitor
Bias input
Input circuit 5 Mohm / 10 nF RC filter
67 Mohm series resistor to prevent signal loss
Test input
Input circuit 47 ohm terminated, charge injection via a 1 pF (nominal)
capacitor. One volt step across 47 ohm gives 1 pC charge
injection (nominal).
Intermediate gain stage
Polarity Jumper setting (order configuration option).
-N non-inverting (for negative charge pulses at CR10 input)
-P inverting (for positive charge pulses at CR10 input)
Gain Jumper settings (order configuration option)
-IG1 0 to x1 adjustment
-IG10 0 to x10 adjustment
-IG100 0 to x100 adjustment

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Shaping amplifier
Output pulse Gaussian unipolar
Shaping time constant Build time configuration selection for CR-200 module:
-T1 100 nsec (240 nsec FWHM)
-T2 250 nsec (590 nsec FWHM)
-T3 500 nsec (1.2 µsec FWHM)
-T4 1 µsec (2.4 µsec FWHM)
-T5 2 µsec (4.7 µsec FWHM)
-T6 4 µsec (9.4 µsec FWHM)
Baseline restorer
Function Build time configuration option (CR-210).
Removes negative DC offset on the output resulting from AC-
coupled signals at high rates. Output signal pulses must be
positive polarity.
Output line driver
Compliance Up to ## V into 50 ohms, ## V into high impedance
Maximum line length Able to drive at least 10 m of RG-58, RG-174 or RG-318 coaxial
cable.
Controls and displays
Controls 21-turn trimpot (DC offset)
21-turn trimpot (pole-zero compensation)
21-turn trimpot (fine gain control)
Internal jumpers for polarity and coarse gain setting.
Displays One LED (power on).
Power
Power input +12 (+2/-4) VDC, -12 (+4/-2) VDC 50 mA typical, each rail.
Physical
Case Stainless steel with mounting flange.
Case protection rating The case is designed to rating IP43 (protected against solid
objects greater than 1 mm in size, protected against spraying
water).
Weight 0.29 kg (0.63 lb).
Operating environment 0 to 35 C (15 to 25 C recommended to reduce drift and offset)
< 80% humidity, non-condensing

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vibration < 0.2 g all axes (1 to 100 Hz)
Shipping and storage
environment
-10 to 50C
< 80% humidity, non-condensing
vibration < 2 g all axes, 1 to 100 Hz
Dimensions (see figures 1 - 3).
Figure 1. CR10 chassis end panels (SHV connectors). Dimensions mm.
DETECTOR
SHV BIAS IN
SHV
TEST IN
LEMO COAX
EPS.00.250.NTN
+/-12V POWER IN
LEMO
EXG.0B.304.HLN
OUTPUT
LEMO COAX
EPS.00.250.NTN
OFFSET ADJUST
POLE/ZERO ADJUST
FINE GAIN ADJUST
POWER LED

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Figure 2. CR10 case plan and side views (SHV connectors). Dimensions mm.
4.1
80.5
2.0114.0
3.66 SLOT
122.3
105.1
131.8
28.4
0.9
62.0

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Figure 3. CR10 case (BNC signal connector option) end panel and plan view. Dimensions mm.
4.1
80.5
2.0114.0
3.66 SLOT
62.0

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9 Installation
9.1 Mounting
The CR10 must be located close to the radiation detector to minimize the effect of cable
capacitance on noise levels. This is most important for detectors that create very small charge
pulses (a 20,000 electrons or less), where the -G0 conversion gain configuration is used. If the
charge pulse is larger, and/or where pulses are being simply counted rather than pulse height
analysed, then around three feet (one meter) of coaxial cable can be used to connect the detector.
This can be done to remove the CR10 from an area of high radiation for example, or to simplify
mounting and cable connections.
The CR10 may be mounted in any orientation, or may be simply placed on a level surface. A
fixed mounting to a secure frame is recommended in a permanent installation for best low
current performance, as this can be degraded by movement and vibration. Four M3 clear holes
are provided in the base flange on a 62 mm by 114 mm rectangular pattern. An adaptor for 35
mm EN 50022 DIN rail is available.
Figure 4. DIN rail mounting.
The mounting position should allow sufficient access to connectors and cable bend radii. Leave
60mm clearance at either end for mating connectors and cable radii.

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Best performance will be achieved if the CR10 is in a temperature-controlled environment. No
forced-air cooling is required, but free convection should be allowed around the case.
9.2 Grounding and power supply
A secure connection should be made via the mounting flange to local ground potential. If the
unit is mounted on an insulating surface, then one of the four mounting screws must be re-
assigned as a grounding connection.
+12 VDC and -12 VDC power should be provided from a suitably-rated power supply with the
following minimum performance:
Output voltage +12 (+4/-2) VDC
-12 (-2/+4) VDC
Output current 50 mA typical, 100 mA maximum each rail
Ripple and noise < 100 mV pk-pk, 1 Hz to 1 MHz
Line regulation Better than 240 mV
9.3 Connection to equipment
9.3.1 Making connections
CAUTION
The CR-10 circuits are sensitive and may be damaged if connections are made while high voltage
is present. Observe the following precautions when connecting cables:
- Ensure HV supplies are turned off and any charge has drained away
- Ensure the CR-10 case is grounded
- Connect the power supply cable
- Connect the signal output and test input cable (if used)
- Connect the detector cable
- Connect the bias in cable (if used)
9.3.2 Typical setup
Figure 5 shows a typical installation to read out a proportional counter in schematic form. The
central wire of the chamber is where the signal is created, and it must be biased to positive high
voltage to produce the electron avalanche. The signal has negative polarity (electrons are

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collected). Since the final shaped pulse output is generally required to be positive polarity to suit
multichannel analysers or pulse counting circuits, and must be positive if the -BR baseline
restoration option is fitted, the CR10 should have the -N polarity configuration. Inside the CR10
the pre-amplifier stage is inverting, so the -N configuration means that no further inverting stages
are used, and the output pulses will be positive.
CR10
Test pulse
generator
+/- 12 VDC
PSU
MCA or
counter
HV bias
PSU
Proportional counter tube
Figure 5. Schematic CR10 installation for readout of a proportional chamber
9.3.3 Cables
Try to locate the CR10 as close to the detector as possible, as far as space and radiation levels
permit. Screened cable between the CR10 and the detector loads the input with capacitance,
which affects both the noise level and the risetime of the input stage. Using a lower capacitance
coaxial cable such as RG-59 or RG-62 will allow longer cable to be used. Anti-triboelectric
cable is recommended to avoid interference from cable movement.
The following figure shows the measured wideband noise as a function of input capacitance for
two input conversion gain options (-G0 1400 mV C-1, -G1 130 mV C-1), and two shaping time
constants (-T2 250 nsec, -T4 1 µsec). The capacitive load was applied by connecting increasing
lengths of RG-58 coaxial cable, with nominal capacitance 0.95 pF cm-1. The measured voltage
noise at the output was converted to input charge based on measured pulse height of a known
detector charge signal.
The plots show that increased shaping time constant gives lower noise across the load curve, and
that the most sensitive input amplifier configuration is the least tolerant of capacitive loading.

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0.0
0.1
0.2
0.3
0.4
0.5
0.6
0 20 40 60 80 100 120 140 160 180 200
RMS noise (fC)
Length of RG-58 cable (cm)
Effect of cable capacitance
CR10-G0-T2 CR10-G0-T4 CR10-G1-T2 CR10-G1-T4
Figure 6. Effect of cable capacitive load on noise