DT5770 SIGNLE CHANNEL MCA FOR HIGH RESOLUTION GAMMA AND X-RAY DETECTOR

INTRODUCTION

ULTRA-COMPACT, STAND-ALONE DIGITAL PULSE PROCESSOR AND MCA WITH USB, ETHERNET CONNECTIVITY

The DT5770 is a compact portable 16k Digital MCA for gamma spectroscopy, integrating analog front-end with programmable gain and possible AC coupling. It is ideally suited for high energy resolution semiconductor detectors, like HPGe and Silicon, connected to a Charge Sensitive Preamplifer (CSP). The unit can also properly operate directly connected to a PMT with inorganic scintillators (e.g. Nal or Csl scintillators), provided exponential pulse shape and decay time above 200 ns.

The DT5770 is equipped with a FPGA featuring the real-time Digital Pulse Processing for Pulse Height Analysis (PHA) making the module a data acquisition system for Nuclear Physics and other applications involving radiation detection. The DT5770 houses USB 2.0 and Ethernet interfaces.
Two ways of operation are foreseen:

  • “Pulse Height Analysis (PHA)”: pulse height histogram (1k-2k- 4k-8k-16k) built at board level
  • “Oscilloscope”: input and internal flters waveforms
PHA settings, acquisition and mathematical analysis are performed through the MC2 Analyzer software GUI, providing out energy spectra in ASCII and N42.42 compliant fles.

FEATURES

  • Analog Input:
    • BNC connector
    • Single ended, DC/AC coupled
    • Both continuous and pulsed reset preamplifiers supported
    • Impedance: 50 Ohm / 1 kOhm (sw selectable)
    • Positive and negative signals accepted
    • Programmable 4-step analog coarse gain corresponding to: 1.25 Vpp, 2.5 Vpp, 5 Vpp, 10 Vpp ranges
    • Bandwidth: DC to 30 MHz
    • Programmable fine gain: 1..100
    • Programmable DC offset adjustment on the input in the full scale range
  • Transistor Reset Preamplifier Support
    • Selectable gains in the range [2:100] in 12 steps
    • AC coupling software selectable (shaper AC ~600ns)
  • ADC
    • Resolution: 14 bits
    • Sampling rate: 150 MS/s
  • Digital Signal Processing
    • Manual and automated trigger threshold adjustment
    • Manual and automated Pole-Zero cancellation; decay time up to 0.65 ms
    • Digital decimation in programmable steps: 2-4-8
    • Digital fine gain
    • Pile-up rejection and Live Time correction
    • Baseline restorer with programmable averaging
    • Adjustable moving average low pass filter to reduce the high frequency noise
  • Preamplifier Power Supply
    • DB9 connector
    • -± 12 V, 100 mA output (DB9/pin4/pin9)
    • -± 24 V, 50 mA output (DB9/pin6/pin7)
    • -Output voltage tolerance: 2%
    • -Voltage ripple < 5 mVpp
  • Operating Modes
    • Pulse Height Analysis (PHA): 16k-channel pulse height histogram internally built up; 1k-2k-4k-8k-16k rebin options at software level
    • Oscilloscope mode for waveforms monitoring
  • Trigger Modes
    • Internal trigger
    • External: channel is triggered by external trigger only (GP I/O 1 or GP I/O 2)
  • Analog / Digital I/O
    • Two GPIO on LEMO connector with multiplexed function
    • Input (Zin 50 Ohm) programmable as: Veto / Gate / Ext. Trigger / Reset
    • Output (22 Ohm Terminated) programmable as: Trigger / Energy probe / Pile-up inhibit / Event rejected / Baseline suspended / Acquisition run/stop / SCA (COMING SOON) / Clock
    • Analog Output (50-Ohm terminated), programmable as: Input signal / Fast Trapezoid / Trapezoid / Energy data / Baseline / Trapezoid - Baseline
  • Communication interface
    • Ethernet connection 10/100BT
    • USB 2.0 compliant
  • MISC
    • Firmware can be upgraded via USB/Ethernet
    • Fully controlled by MC² Analyzer spectroscopy Software
    • For developers: general purpose C libraries with demo samples available
    • Dimensions: 106 W x 38 H x 128 L mm³
    • Weight: 300g

FUNCTIONAL DIAGRAM

The DT5770 operates on the analog signals provided on its input by applying a PHA algorithm implemented in the equipped DPP-PHA Firmware for the Digital Pulse Height Analysis.
DT5770 is an acquisition system that receives the analog signal and performs the A/D conversion (@150 MS/s, 14 bit) at the input of the module, just after an analog input stage whose purpose is to adapt the signal voltage swing to the dynamic range of the ADC. After the A/D conversion, the stream of samples is managed by an FPGA programmed to perform on-line Digital Pulse Processing in order to implement the MCA based on the Pulse Height Analysis (DPP-PHA); the algorithms implemented in the DPP-PHA firmware are based on the trapezoidal filter (Moving Window Deconvolution) for the calculation of the pulse height. The energy spectra are build up in the on-board FPGA and made available for the readout.

CAEN MC²Analyzer

The software is able to completely control and manage a set of boards acquiring data simultaneously, making therefore a multi-board system a "Multichannel - Multichannel Analyzer". MC²A allows the user to set all the relevant DPP-PHA parameters for each acquisition channel (like trigger threshold, shaping parameters, etc.), handle the communication with the connected boards, run the data acquisition and plot both waveforms for on-line monitoring of the acquistion and histograms. It can also control the HV power supplies provided in DT5780 and Gamma Stream. Moreover, it is able to perform advanced mathematical analysis on both the ongoing histograms and collected spectra: peak search, background subtraction, peak fitting, energy calibration, ROI selection, dead time compensation, histogram rebin and other features available. MC²A can provide as output both the energy - time stamp lists from each enabled channel for off-line analysis and spectra as 1-column ASCII or ANSI N42.42 compliant files, including all the useful information for the commercial or user defined software for quantitative analysis. MC²A is also able to manage hardware coincidences from different channels to the same board and to handle different digitizers.