Advance Product Information

Digital Pulse Processor
for Scintillation Detectors

DP5GFeatures• Integrated preamplifier, shaping amplifier, and MCA
optimized for scintillation systems• Processes PMT anode signal, giving completespectrum• Available as processor alone or with power supply
and interface board• For OEMs or custom laboratory users• Highly configurable• Low Power: 600 mW typical• Small Size: 2.0 in x 1.75 inPulse Processing & MCA• Includes charge sensitive preamplifier• Peaking time commandable from 0.1 to 102.4 µs• Commandable flat top duration from 0.05 to 51.2 µs• Pile-up rejection & risetime discrimination• Up to 8k output MCA channels

Communications• Interfaces: RS-232, USB, Ethernet, I2C, auxiliary• Oscilloscope mode - DAC output for pulse
monitoring and adjustment• Onboard µcontroller with 8051-compatible core
• Software for PC data acquisition and control(includes SDK)• Many configurable auxiliary inputs and outputs

Shown in Actual Size: 2.0 in. x 1.75 inApplications• X-ray and gamma ray detectors• Nuclear Instrumentation• Portable, battery operated systems• OEM & Special Applications• Process Control• Research and Teaching

Overview
The Amptek DP5G is a state-of-the-art, high performance, low power digital pulse processor designed
for use in scintillation spectroscopy systems. Connected to the anode of a PMT, it includes a charge sensitive preamplifier and a digital pulse processor, which replaces both the shaping amplifier and the MCA ina traditional nuclear spectroscopy system. The DP5G offers several advantages over traditional systems,
including higher performance, enhanced flexibility, small size, and low cost.
The DP5G is one component in a complete gamma-ray spectrometer, shown in the diagram below. TheDP5G includes only the core signal processing functions. A complete system must also include a detector
module (scintillator, PMT, HV supply, tube base) and interface circuitry with power supplies and connectors
for the serial connection. Amptek can provide an OEM user with the DP5G alone, or can provide it witha PCG interface module, or can provide a complete system, including the detector module. The completesystem is a separate Amptek product, the GammaRad5.
The DP5G represents the latest generation in digital pulse processing. The DP5 family is an enhanced
replacement for Amptek’s older DP4 family. The DP5G is a variant of the DP5, optimized for scintillation
readout. The DP5 technology includes faster peaking times, improve pile-up rejection and pulse shape discrmination, better dead time correction, additional features such as a “List Mode”, and enhanced interfaces.

Amptek, Inc.

Tele: +1 781-275-2242

14 DeAngelo Drive, Bedford MA 01730

Fax: +1 781-275-3470 sales@amptek.com

www.amptek.com

Specifications
Pulse Processing Performance

Conversion TimeNoneGainCombination of coarse and fine gain
yields overall gain continuously
adjustable from x1.2 to x8.1.

Presets

Time, total counts, counts in an ROI,counts in a channel.

Coarse Gain

1.6, 2.6, 4.1, 6.5

MCS Timebase

10 ms/channel to 300 s/channel

Fine Gain

Adjustable between 0.75 and 1.25.

ADC Clock Rate

20 or 80 MHz, 12 bit ADC

External MCA
Controls - Gate
Input

Pulses accepted only when gated on
by external logic. Input can be active
high or active low.

Pulse Shape Trapezoidal

Semi-Gaussian amplifier with shaping
time τ has a peaking time of 2.2 τ andis comparable in performance with thetrapezoidal shape of the same peakingtime.

Counters

Slow channel events accepted by MCA.
Incoming counts (fast channel counts
above threshold), event rejected by
selection logic, and external event
counter.

Peaking Times

Software selectable peaking times
between 0.05 and 102 µs, corresponding
to semi-Gaussian shaping times of 0.8
to 45 µs.

HardwareFlat Top Times

63 software selectable values for eachpeaking time (depends on the peakingtime), >0.05 µs.

Max Count Rate

With a peaking time of 0.2 µs, 4 MHz
periodic signal can be acquired.

Microprocessor

Silicon Labs 8051F340 8051-compatible
core.

External Memory

512 kb low-power SRAM

FirmwareSignal processing is programmed
via firmware, can be upgraded in thefield.

Communications
RS-232Standard serial interface @ 115 Kbaud.

USB

Standard 2.0 full speed (12 Mbps).

Fast Channel Pulse 60, 120 ns @ 80 MHZ
Pair Resolving Time 240, 480 ns @ 20 MHZ

Ethernet

Standard 10base-T. (UDP)

Pile-Up Reject

Analog Input

The output from a PMT, the anode, isconnected to the analog input of theDP5G. The first stage of the DP5G is acharge amplifier with a conversion gainof 0.15 mV/pC (CF=6.8 nF). The input
connector is a MMCX jack.

Power+3.3 VDC.

DAC Output

Used in oscilloscope mode to view theshaped pulse and other diagnostic
signals. Range: 0 to 1 V.

Dead Time Per Pulse 1.05x peaking time. No conversion
time.

Connections

Pulses separated by more than the fastchannel resolving time, and less than
1.05x peaking time are rejected.

Baseline Restoration 16 software selectable slew rate- Asymmetricsettings.

MCA Performance
Number ofchannels

Commandable to 256, 512, 1024,2048, 4096, or 8192 channels, MCA
or MCS.

Bytes per channel

3 bytes (24 bits), 16.7 M counts.

Preset AcquisitionTime

10 ms to 466 days.

Data Transfer Time

USB: 1k channels in 6 ms
RS-232: 280 ms

Power+3.3 V

20 MHz clock: 180 mA typical
80 MHz clock: 240 mA typicalInput Range

3.3 ± 0.1V

Example of a complete gamma-ray spectrometer.
Detector Module

Scintillator

DP5G Digital Pulse Processor

ADC

PMTCharge
AmplifierHigh Voltage
Bias Supply

Digital Pulse
Processing(FPGA)

Spectrum
Memory(MCA)

Microcontroller

AnalogPrefilter

Auxiliary I/O

Low Voltage
Power Supply+5V

PCG Interface Module

InterfaceHardware

USB
Ethernet
RS232

ComputerSpecifications (con’t)
PhysicalADC

Size2.0” x 1.75“Weight13 g

General and Environmental
OperatingTemperature-40 °C to +85 °C.

Warranty Period

1 year.

Typical Device
Lifetime

5 to 10 years, depending on use.

Long-term Storage

10+ years in dry environment.

Typical Storage and -40 °C to +85 °C, 10 to 90% humidity
Shipping
non-condensing.
Compliance

Architecture

RoHS Compliant

Auxiliary Inputs and Outputs
These signals are not required for the primary use of theDP5G: acquiring spectra and transmitting them over the serial interface. These are generally “low level” logic signals associated with each pulse processed by the DP5G. They are
primarily used for synchronizing the DP5G data acquisition toexternal hardware and for direct counter/timer outputs fromthe DP5G. The signals are described below.
Single Channel
Analyzers

8 SCAs, independent software selectable LLDs and ULDs, LVCMOS (3.3 V)
level (TTL compatible).

Digital Outputs

2 independent outputs, software selectable between 8 settings including
INCOMING_COUNT, PILEUP, MCS_TIMEBASE, etc. LVCMOS (3.3V) levels (TTLcompatible).

Digital Inputs

2 independent inputs, software selectable for MCA_GATE, EXTERNAL_COUNTER.

I/O

2 general purpose I/O lines for custom
application.

Digital Oscilloscope Displays oscilloscope traces on thecomputer. Software selectable to show
shaped output, ADC input, etc., to assist
in debugging or optimizing configurations.

The ADC digitizes the output of the analog prefilter at a 20
or 80 MHz rate then sends it in real time to the digital pulseshaper. 12 bit ADC is used.

Digtal Pulse Shaper
The ADC output is processed continuously using a pipelinearchitecture to generate a real time shaped pulse. This carries
out pulse shaping as in any other shaping amplifier. The
shaped pulse is a purely digital entity. Its output can be routed
to a DAC, for diagnostic purposes, but this is not necessary.
There are two parallel signal processing paths inside the DPP,
the “fast” and “slow” channels, optimized to obtain different data
about the incoming pulse train. The “slow” channel, which hasa long shaping time constant, is optimized to obtain accurate
pulse heights. The peak value for each pulse in the slowchannel, a single digital quantity, is the primary output of thepulse shaper. The “fast” channel is optimized to obtain timing
information: detecting pulses which overlap in the slow channel,
measuring the incoming count rate, measuring pulse risetimes,etc.
The DP5G uses trapezoidal pulse shaping, which offers
high energy resolution, reduces ballistic deficit, and provides
excellent baseline stability at high count rates.

Pulse Selection Logic
The pulse selection logic rejects pulses for which an accurate
measurement cannot be made. It includes pile-up rejection,
risetime discrimination logic for an external gating signal,etc. At high count rates, the DP5G has both better pile-up
rejection and higher throughput than a traditional, analog
shaping amplifier.

Histogramming Memory
The histogramming memory operates as in a traditional MCA.
When a pulse occurs with a particular peak value, a counter ina corresponding memory location is incremented. The result
is a histogram, an array containing, in each cell, the number of
events with the corresponding peak value. This is the energy
spectrum and is the primary output of the DP5G.
The unit also includes several counters, counting the total
number of selected pulses but also counting input pulses,
rejected events, etc. Auxiliary outputs include 8 different
single channel analyzers, and both a DAC output and a digital
output showing pulse shapes from several points in the signal
processing chain.

Interface
The DP5G includes hardware and software to interface
between these various functions and the user’s computer. A
primary function of the interface is to transmit the spectrum
to the user. The interface also controls data acquisition, bystarting and stopping the processing and by clearing thehistogram memory. It also controls certain aspects of theanalog and digital shaping, for example setting the analog
gain or the pulse shaping time.
The interface includes a microcontroller and serial interface
hardware. RS232, USB, and Ethernet are currently available.

Software (con’t)

PCG and Interface
The DP5G includes only the core signal processing functions.
The DP5G does not include the interface connectors or low
voltage power supplies which are found on the DP5. To use
the DP5G, a user can either (1) purchase a PCG interface board
from Amptek or (2) implement a custom interface solution.
These functions were removed from the DP5G to make it assmall as possible. OEM customers integrating the DP5G into
their complete system usually have a power supply and connectors. Including them on the DP5G was duplicative andwould make the board larger than necessary.

Interface Software
DPPMCA Software The DP5G can be controlled by the Amptek
DPPMCA display and acquisition software. This software canbe used for control and display of the DP5G and supports regions of interest (ROI), calibrations, peak searching, and so on.
The DPPMCA software includes a seamless interface to theXRF-FP quantitative X-ray analysis software package.
Example of DPPMCA display and acquisition software.

Amptek offers an interface board, the PCG, which includes
these functions. The DP5G and PCG together offer essentiallythe same electrical functionality as the DP5 configured for scintillators. The figure below illustrates a complete gamma-rayspectrometer solution. Amptek also offers a complete spectrometer solution, the GammaRad.
DP5G (top) mated with the PCG (bottom)
DPP SDK The DP5G comes with SDK: C++ classes. The user
can use this library to easily write custom code to control theDP5G for custom applications or to interface it to a larger system. Examples are provided in VB, VC++, etc. on how to use
the APIVB Demonstration Software The VB demonstration software
runs on a personal computer and permits the user to set theDP5G parameters, to start and stop data acquisition, and tosave data files. It is provided with source code and can be
modified by the user. This software is intended as an exampleof how to manually control the DP5G through either the USB,ethernet, or RS-232 interface without the DPP SDK.

Software
There are two distinct software packages that are needed forthe DP5G: embedded software that runs on the microcontroller on the DP5G (firmware), and acquisition and control
software that runs on the attached computer. A complete
software platform with examples is provided to aid in software development for OEM and custom applications.

Example of demonstration software supplied with the DP5G
for data acquisition (source code provided).

Embedded Software
The embedded software is responsible for controlling thepulse processing, controlling the MCA, carrying out somedata processing, and interfacing with the personal computer.
This software is fixed and cannot be modified by the user.
Firmware updates will be released by Amptek and can be uploaded in the field by the user.

Amptek, Inc.

Tele: +1 781-275-2242

14 DeAngelo Drive, Bedford MA 01730

Fax: +1 781-275-3470 sales@amptek.com

www.amptek.com