microDGF Compact Digital Pulse Processor for embedded high-resolution Gamma Applications

 

The microDGF is a variant of the highly successful microDXP, with the analog front end upgraded specifically for high resolution gamma spectroscopy with HPGe detectors. Premium energy resolution is achieved with HPGe detectors, even at moderate to high count rates.

  • nuclear spectroscopy Designed for high resolution gamma spectroscopy with HPGe detectors.
  • Credit-card size board for compact detector systems.
  • 40 or 80 MSPS 14-bit digitization, 8K MCA channels.
  • Operating parameters saved onboard in non-volatile memory.
  • USB-2.0 or RS-232 communication.
  • Digital I/O lines for external instrument control and feedback.
  • Open source driver libraries for custom DAQ control
  • Development Kit board available for plug-and-ply power and communication and easy access to auxiliary I/O lines.

Downloads

 

Applications

The microDGF is a complete, low power digital pulse processor the size of a credit card, designed for high resolution gamma detectors such as HPGe in both portable and embedded applications. The microDGF differs from the microDXP by providing front-end analog circuitry designed to match the low noise and high dynamic range of HPGe detectors. Most other gamma-ray detector types (solid state or scintillator) can be operated successfully with the microDXP.

Applications:

  • High Resolution Gamma-ray Spectroscopy with HPGe.
  • Compact solution for HPGe portable or special configurations.

More about Applications…

 

Technical Data

In common with all XIA digital pulse processors, the microDGF replaces the amplifier and MCA functions in conventional spectroscopy systems. The standard digitization rate is 40 MSPS, with an option for 80 MSPS for faster timing applications. The firmware for the FPGA and DSP is stored in a pre-loaded non-volatile flash memory. A PIC processor handles communications, boot-up, dedicated acquisition routines, and power management. In addition to serial I/O, auxiliary digital I/O are available to control external instrumentation, including the capability for I2C. XIA would be pleased to discuss developing custom DSP control code on an NRE basis.

The Development Kit includes the hardware and software necessary to get started with the microDGF, and provides a motherboard (the microCOMU) for filtered power, communication and easy access to I/O lines. All customers must purchase a development kit with their first microDGF order.

Features

  • Credit-card sized unit replaces shaping amplifier, pile-up inspector and multi-channel analyzer.
  • Low noise front-end and high dynamic range for high resolution gamma-spectroscopy.
  • Peaking times from 100ns to 24µs (with 40 MSPS ADC)
  • High level integration of control and acquisition parameters into reconfigurable sets stored in non-volatile memory.
  • Accurate ICR and Live-Time reporting for precise dead-time corrections.
  • USB 2.0 or serial RS-232 communications.
  • Alternative IDMA parallel interface supports a wide of alternative communications.
  • Real-time control via 4 general purpose I/O lines, including standard I2C interface.
  • XIA ProSpect software, or open source driver libraries available for custom DAQ control.

Specifications

Inputs

 Analog RC-feedback preamplifiers with up to ± 4.5V total input range w/o attenuation. Other voltage ranges with onboard attenuation.

User defines input impedance.
Digital Gate (TTL 3.3V) signal used to suppress data acquisition
4 general purpose digital I/O lines for custom applications

Data I/O

 USB 2.0 On-board USB 2.0 is available
RS-232 RS-232 Serial communications up to 921 kBaud
OEM OEM Option 1: Analog Devices high-speed serial port (SPORT) via the flat-flex interconnect
OEM Option 2: 16-bit IDMA bus; 4 general purpose digital I/O lines, two of which can be configured for industry standard I2C interface; connected via a high-density board-to-board connector. The microComU USB interface employs this connection.
Real-Time I/O 4 general purpose digital I/O lines, two of which can be configured for industry standard I2C interface

Digitizer

 ADC 14-bits at 40 MSPS standard

Digital Controls

 Gain Two gain options are available, combined with a digital fine gain adjustment ranging +/- 6dB
Gain Option 1 (standard): 25.5 dB range with 16 discrete computer-controlled gain settings
Gain Option 2: Fixed gain for embedded applications, lowest power consumption
Offset DC offset adjustment: -4.4V to +4.4V
(For RC-decay preamplifiers; assumes no input attenuation)
Filtering Three triangular/trapezoidall filters are employed to suppress noise, and to detect and acquire baseline and energy data:
Fast Filter: fully adjustable, from 50 ns to 6.4 μs*
Intermediate Filter: tracks with Slow filter, from 50 ns to 6 μs*
Slow Filter: 24 pre-selected peaking times from 100 ns to 24 μs*, with adjustable gap/dwell time. *These numbers assume standard 40 MSPS ADC, and should be scaled for 80 MSPS option.
Thresholds A separate 12-bit (0-4095) threshold can be enabled/disabled and adjusted for each of the three filters
Pileup Two pileup rejection settings :
Fast filter time-over-threshold, aka maximum width constraint
Interval-between-events, aka peak interval constraint
Data collection MCA limits and number of bins
Dynamic Range

Data Outputs

 MCA Up to 8K channels (24 bits deep)
Statistics Livetime, runtime, input counts, output counts, overflows and underflows
Diagnostics Oscilloscope, baseline distribution, access to raw DSP memory

Hardware

 Power Requirements +/- 5V @ 50 mA clean supply, or +/-5.25V @ 50 mA dirty supply to feed on-board regulators
+3.3V @ 150 mA
Dimensions 2.125″ W x 3.375″ L

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Applications