Pyramid D100 User manual

D100
Digital Pulse Processor
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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1Contents
Safety Information ......................................................................................................................................................5
Models...........................................................................................................................................................................7
Scope of Supply............................................................................................................................................................8
Optional Items .............................................................................................................................................................9
Power supplies..........................................................................................................................................................9
Signal cables and cable accessories.........................................................................................................................9
Data cables...............................................................................................................................................................9
Fiber-optic loop........................................................................................................................................................9
Intended Use and Key Features ...............................................................................................................................10
Intended Use...........................................................................................................................................................10
Key Features...........................................................................................................................................................11
Specification...............................................................................................................................................................12
Installation .................................................................................................................................................................15
Mounting.................................................................................................................................................................15
Grounding and power supply .................................................................................................................................15
Connection to signal source ...................................................................................................................................16
Basic setup .........................................................................................................................................................16
Signal cables ......................................................................................................................................................17
Signal cables ......................................................................................................................................................17
Getting Started with the PSI Diagnostic host software..........................................................................................19
Installing the PSI Diagnostic Program ..................................................................................................................19
Running the PSI Diagnostic Program....................................................................................................................19
Running the PSI Diagnostic program.....................................................................................................................21

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Acquiring spectra with the PSI Diagnostic program..............................................................................................23
Principle of Operation...............................................................................................................................................26
Wideband digital pulse processing.........................................................................................................................26
D100 Circuit Overview...........................................................................................................................................27
Optimizing the Pulse Processing Algorithm...........................................................................................................30
Overview of the FPGA algorithm...........................................................................................................................30
Regions of interest .............................................................................................................................................30
Data processing stages .......................................................................................................................................31
Pulse processing user parameters..........................................................................................................................32
Shaping Time .....................................................................................................................................................32
Peak Width.........................................................................................................................................................32
Shaping Samples................................................................................................................................................32
Derivative Discriminator....................................................................................................................................32
Pulse Discriminator............................................................................................................................................32
Pile Up ...............................................................................................................................................................33
Decay Time........................................................................................................................................................34
Gain, Offset........................................................................................................................................................35
Connectors .................................................................................................................................................................36
Front panel connectors...........................................................................................................................................36
Photomultiplier control ......................................................................................................................................36
Test I/O ..............................................................................................................................................................36
Pulse signal input ...............................................................................................................................................37
Ground lug .........................................................................................................................................................37
Rear panel connectors............................................................................................................................................37
Power input ........................................................................................................................................................37
Fiber-optic direct data stream output .................................................................................................................37
Fiber-optic loop communications ......................................................................................................................37
Controls and Indicators............................................................................................................................................38
Front panel controls...............................................................................................................................................38
Rear panel controls.................................................................................................................................................38
Address switch ...................................................................................................................................................38

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Front panel indicators............................................................................................................................................39
LED block..........................................................................................................................................................39
Rear panel indicators .............................................................................................................................................39
Fault-finding ..............................................................................................................................................................40
Maintenance...............................................................................................................................................................42
Returns procedure.....................................................................................................................................................43
Support.......................................................................................................................................................................44
Declaration of Conformity........................................................................................................................................45
Revision History.........................................................................................................................................................46

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2Safety 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.
CAUTION. The D100 does not generate high voltages, but is designed to control a high voltage
supply for a photomultiplier, which may typically be rated from 1000 to 2000 V DC. The user
must therefore exercise appropriate caution when using the device and when connecting cables.
Power should be turned off before making any connections.
CAUTION. The D100 features a DC-coupled input. It must only be used with photomulipliers
that produce a ground-referenced signal.
The unit must not be operated unless correctly assembled in its case. Protection from high
voltages could be impaired if the unit is operated without 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.
The unit is designed to operate from +24VDC power, with a maximum current requirement of
200 mA. A suitably rated power supply module is available as an option. Users who make their
own power provision should ensure that the supply cannot source more than 1500 mA.
A safety ground must be securely connected to the ground lug on the case.
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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3Models
D100 Digital pulse processor unit.
-CxRy Input amplifier feedback option capacitance x pF, resistance y kohm.
Example:
D100-C100R1.0 D100 with 100 pF and 1.0 kohm parallel feedback.

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4Scope of Supply
D100 model as specified in your order.
USB memory stick containing:
User manual
PSI Diagnostic software guide
Software installation guide
PSI diagnostic software files
USB drivers and utilities
Optional items as specified in your order.

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5Optional Items
5.1 Power supplies
+24 VDC 1.5 A PSU (universal voltage input, plug receptacle for standard IEC C8 socket) with
output lead terminated in 2.1mm threaded jack.
5.2 Signal cables and cable accessories
Cable, coaxial, BNC to BNC, 1 m, for input signal.
Cable, four-pin mini-DIN to unterminated, 3 m, for temperature sensing and pulser LED control.
Cable, six pin mini-DIN to unterminated, 3 m, for HV PSU control.
5.3 Data cables
Fiber-optic cable, 5m, 1 mm plastic, ST terminated.
Fiber-optic cable, 25m, 200 µm silica, ST terminated.
5.4 Fiber-optic loop
A100 serial port to fiber-optic loop adaptor.
A200 USB to fiber-optic loop adaptor.
A300 Ethernet to fiber-optic loop adaptor.
A500 intelligent multi-loop cell controller with Ethernet interface and direct input channels for
up to ten parallel D100 data streams.

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6Intended Use and Key Features
6.1 Intended Use
The D100 is intended for the counting and spectrometry of single event current pulses generated
by sodium iodide scintillator/photomultiplier detectors operated in pulse-counting mode. The
D100 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. The unit may be used stand-alone, or networked with other devices and integrated
into a larger system. 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.

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6.2 Key Features
DC-coupled, wide-band analog signal stages.
Fast ADC for direct digitization of detector signal.
FPGA-based digital signal processing of detector signal.
On-board real-time pulse-height analysis / histogram generation.
On-board real-time pulse shape analysis for pile-up detection and invalid pulse rejection.
Pulse-pair resolution for sodium iodide detectors down to 500 nsec with individual pulse energy
spectrometry, or down to 50 nsec for counting.
Real-time data stream output via dedicated fiber-optic channel for region of interest counts.
Bi-directional fiber-optic communications channel for all control and sensing.
Built-in control for photomultiplier HV supply.
Built-in temperature sensing for detector stabilization.
Built-in control for LED test pulser.
Fast fiber-optic serial interfaces built-in. Selectable baud rates.
Can be operated in a fiber-optic serial communication loop with up to fourteen other devices.
100BaseT Ethernet available through the A300 and A500 interfaces.

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7Specification
Inputs One, DC-coupled
Input impedance < 0.1 ohm in standard configuration.
Input analog channel
risetime
< 50 nsec
Digitization 14 bit, 80 MHz.
Pulse pair resolution <= 500 nsec with pulse height analysis of both pulses
< = 50 nsec with both pulses counted
Deadtime < = 50% of pulses rejected at 500 kHz average input rate
Pulse size analysis 1024 channel on-board histogramming
Pulse shape analysis Pulses accepted for processing based upon width.
Baseline compensation for pulse decay tail
Power input +24 VDC (+/-2 V), 150 mA typical without drain on 5 V output,
200 mA with maximum drain on 5 V output.
Power output +5 VDC (+/- 0.1V), 200 mA maximum
Controls Address: sixteen position rotary switch (01 to 0A valid)
Indicators Four status LEDs: power, activity, network, device
Case Stainless steel folded case.
Case protection rating The case is designed to rating IP43 (protected against solid
objects greater than 1mm in size, protected against spraying
water).
Weight 0.27 kg (0.6 lb).
Operating environment 0 to 35 C (15 to 25 C recommended to reduce drift and offset)
< 70% humidity, non-condensing
vibration < 0.1g all axes (1 to 1000Hz)
Shipping and storage
environment
-10 to 50C
< 80% humidity, non-condensing
vibration < 2 g all axes, 1 to 1000 Hz
Dimensions (see figures 1 and 2).

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Figure 1. D100 chassis end panels. Dimensions mm.
Status LEDs
Signal Input
BNC
M3 Ground Lug
PMT Control
6-Pin Mini DIN TEST
4-Pin Mini DIN
Address
Selector
+24VDC Power In
2.1mm Jack
Fiber-optic Direct
ST Bayonet
Fiber-optic TX
ST Bayonet
Direct Xmit
Power Address
Rcv
Fiber-optic RX
ST Bayonet

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4X
3.66 Mounting Hole
77.5
80.2
3.6
158.1
147.1
28.2
0.74
62.0
140.0
Figure 2. D100 case side and plan views. Dimensions mm.

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8Installation
8.1 Mounting
The D100 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
performance. Four clear holes are provided in the mounting flange on a 140 mm by 62 mm
rectangular pattern (see figure 2) for fixing to surfaces with a corresponding pattern of M3
threaded holes or studs.
We recommend that the signal connection to photomuliplier base should be of minimum possible
length, and not exceeding 2 m to prevent possible pulse shape degradation due to capacitive
load. Good quality 50 ohm coaxial cable should be used.
The mounting position should allow sufficient access to connectors and cable bend radii. 60 mm
minimum clearance is recommended at either end of the device.
Best performance will be achieved if the D100 is in a temperature-controlled environment. No
forced-air cooling is required, but free convection should be allowed around the case.
The D100 must not be mounted in a place with high flux of ionizing radiation, as this could lead
to soft errors and possible incorrect processing of signals. To keep the potential error rate below
one event per day, we recommend a maximum background dose rate of 1 mSv / hr.
8.2 Grounding and power supply
A secure connection should be made using a ring lug, from the M3 ground lug to local chassis
potential.
+24 VDC power should be provided from a suitably-rated power supply with the following
minimum performance:
Output voltage +24 +/- 0.5 VDC
Output current 500 mA minimum, 1500 mA maximum
Ripple and noise < 100 mV pk-pk, 1 Hz to 1 MHz
Line regulation < 240 mV
The D100 includes an internal automatically re-setting PTC fuse rated at 1.1 A. However the
external supply should in no circumstances be rated higher than the D100 connector limit of 5 A,
and a maximum of 1.5 A is recommended.

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8.3 Connection to signal source
8.3.1 Basic setup
Figure 3 shows a typical installation for a single sodium iodide / photomultiplier in schematic
form.
Photomultiplier
NaI Base D100
HV PSU
Pulser LED +24V in
A500
Signal Data stream
Comms
HV control
Temperature sense and pulser
HV
Figure 3. Schematic D100 installation
The fiber-optic communication channel is a looped system. Up to 15 devices, which could all be
D100s, or a mix of various devices) can be connected to a host computer via the A100, A200 or
A300 interfaces.
CAUTION. The D100 has a DC-coupled input, and thus must not be used with
photomultipliers that have the signal sitting on a high-voltage. Connecting the D100 input to a
high voltage will result in serious damage and will void warranty.
The D100 is optimized for DC-coupling direct to the anode. AC-coupled operation, with a
blocking capacitor in the photomultiplier base, is also possible, albeit with some degradation in
spectrometry performance. Contact your supplier or Pyramid Technical Consultants, Inc. for
information about firmware updates to optimize performance in AC-coupled systems. If you are
in any doubt about the suitability of your photomultiplier, please consult your supplier or
Pyramid Technical Consultants, Inc. before attempting to use the D100.
If you are using a photomuliplier, the base must not include a pre-amplifier, because the D100 is
designed to receive the anode current pulses directly. The high voltage supply may be external
or integrated with the base. The dynode voltage division may be resistive or active.

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If the anode is connected to ground with a load resistor in the photomultiplier base (RLin figure
3), then this should have a value of 1 kohm or greater. A 50 ohm load resistor is common in
systems where the signal is intended to be transmitted via 50 ohm coax to the 50 ohm input of a
remote current amplifier. Use of a 50 ohm load resistor with the D100 will degrade the pulse
shapes considerably, however, and is not recommended.
The D100 should be located as close to the source of the signal as possible. If space permits, it
can be connected directly to the photomultiplier base with a suitable through connector. Long
signal cables increase the chances of seeing unwanted signals and noise. A maximum length of
2m is advised. Longer cables may be used, but the energy resolution and ability to discriminate
good pulses from bad may be degraded.
8.3.2 Signal cables
Good quality coaxial cable such as RG174U or RG-58U should be used, terminated in a BNC
connector at the D100 end, and a connector to suit the photomultiplier base at the other. The
cable impedance is not critical, but the length should not exceed 2 metres to avoid degradation of
the pulse shapes. A direct connection of the D100 to the base is possible using a BNC through
connector where space permits.
8.3.3 Multi-channel systems
Combining the D100 with the A500 real-time cell controller allows multi-detector systems to be
configured, with data correlation across all the channels. The A500 provides five
communications loops, each of which can service up to fifteen devices. However, by using the
fast data output on the D100, you can configure a multi-channel system that allows simultaneous
pulse energy analysis and timing. One A500 can service up to ten fast data stream inputs, and so
control and coordinate the data from ten parallel D100s. Each incoming pulse in each detector is
analyzed in real time into one of up to 50 pre-defined energy regions of interest by the D100.
The result is transmitted immediately as a byte of digital data via the fast data channel to the
A500. By grouping the incoming data from all D100s at known spatial locations into time bins,
the A500 is able to build up a time, space and energy-resolved picture.
Very large detector arrays can be configured by linking groups of ten A500s under one master
A500, and then grouping these in another layer if required. Arrays of hundreds of detectors can
be operated in this way. Figure 4 illustrates a configuration for coordinated data acquisition
from 100 scintillation detectors.

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PhotomultiplierNaI Base D100
HV PSU
PhotomultiplierNaI Base D100
HV PSU
PhotomultiplierNaI Base D100
HV PSU
PhotomultiplierNaI Base D100
HV PSU
PhotomultiplierNaI Base D100
HV PSU
PhotomultiplierNaI Base D100
HV PSU
PhotomultiplierNaI Base D100
HV PSU
PhotomultiplierNaI Base D100
HV PSU
PhotomultiplierNaI Base D100
HV PSU
PhotomultiplierNaI Base D100
HV PSU
Comms
loop
Fast data
channels
A500
A500
A500
A500
A500
A500
A500
A500
A500
A500
Ethernet
A500
Figure 4. Example multi-channel system using the A500 real-time cell controller

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9Getting Started with the PSI Diagnostic host software
Before installing the D100 in its final location, and if it is the first time you have used a D100,
we recommend that you familiarize yourself with its operation on the bench. You can check the
unit powers up correctly, establish communications, and operate peripheral devices such as HV
supplies. The Pyramid Technical Consultants, Inc. PSI Diagnostic host software, provided with
your D100, provides a simple means of doing this.
9.1 Installing the PSI Diagnostic Program
The PSI Diagnostic is a stand-alone program which allows you to read, graph and log data from
the D100, and set all the important acquisition control parameters. For some applications it may
be adequate for all of your data acquisition needs.
The D100 is supplied with software programs and drivers on a USB memory stick. We
recommend that you copy the files into a directory on your host PC. Check the Pyramid
Technical Consultants, Inc. web site at www.ptcusa.com for the latest versions.
The program runs under the Microsoft Windows operating system with the 2.0 .NET framework.
This has to be installed before the PSI Diagnostic. Most new PCs have .NET 2.0 already
installed. The installer will warn if it is not already installed, and direct you to Microsoft web
site where it can be downloaded at no charge.
Install the PSI Diagnostic by running the PTCDiagnosticSetup.msi installer, and following the
screen prompts. Once the program has installed, you can run the Diagnostic at once.
9.2 Running the PSI Diagnostic Program
1) Inspect the unit carefully to ensure there is no evidence of shipping damage. If there appears
to be damage, or you are in doubt, contact your supplier before proceeding.
2) Connect +24 V DC power but no other connections. The power LED should illuminate when
the power is applied, and the other three LEDs should flash.
4) Set the address rotary switch to position “1” (address 1).
5) Run the PTCDiagnostic host program on a Windows PC.
6) Connect a fiber optic loop adaptor (A100, A200, A300 or A500) to the PC. Connect to the
loop adaptor to the D100 via fiber-optic cable. There is no need to connect to a detector at this
stage.
Note that it is possible to connect a D100 via a simple RS-232 to fiber-optic through converter
such as the Group 3 Model FTR. However this means that the fiber-optic loop and thus D100
have to work at 115k bps rather than the normal 10M bps. To allow this, you would need to
open the D100 case and fit a link to JPR2 option position 1. We do not recommend this
configuration for general use, due to the much reduced data rate.
7) Start the PSI Diagnostic. It will search the available communication channels on the PC and
present a search list. If you are using an A300 or A500 the list does not already include its IP
address, enter this into the edit box followed by :100 for the network port (for example

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192.168.100.100:100), and click “Add”. The network port is fixed at :100 in A500s. Future
versions may lift this restriction in case there are conflicts on particular networks.
Figure 5. PSI Diagnostic Search Utility
Check the box next to the ports you want included in the search. Click “start” and the program
will search for loops and devices on all checked options.
The LAN Broadcast search uses information from the PC operating system to search for A500s
over the whole of your local network. This will generally take longer than going directly to a
known IP address.
A few seconds after you click the “Start” button, the program should find the D100 (plus any
intelligent loop controllers such as the A500). Expanding the tree in the System window will
reveal the all devices that were discovered. Clicking on any discovered device will open its
specific window.
8) Now you can explore the D100 PTCDiagnostic screens.
9.3 Running the PSI Diagnostic program
Clicking on the D100 entry in the System window search tree brings up the D100 screen with the
data tab showing. This is where energy spectra will display, where you can see readbacks for
temperatures, and set the DAC output that programs a high voltage supply for a multiplier.