nuclear-spectroscopy-productsThe Pixie-32 is a 32-channel data acquisition system designed for instrumenting large scale radiation detectors in the Nuclear Physics community at relatively low cost, and offers the following advantages:

  • Digital spectrometry and waveform analysis for 32 input signals per module in compact 3U PXIe format.
  • PCI Express data transfer supports read out of multiple modules in parallel.
  • Adaptable front-end to match a range of experiments and applications.
  • High Density front panel input connector for compact connectivity.
  • Cost per channel reduced by up to x10.




The Pixie-32 is a true multi-channel spectrometer that not only digitally captures incoming waveforms but also provides good time and energy resolution at a per channel cost up to 10 times lower than other digital readout modules of similar capability. Applications include:

  • HPGe detector arrays
  • Scintillation detector arrays
  • Silicon detector arrays
  • Gas counters
  • Real-time pulse-shape discrimination
  • Waveform analysis
  • Time dependent spectroscopy

More about Applications…


Technical Data

Taking advantage of new low cost, high density ADC components, this new member of XIA’s Pixie spectrometer family is designed to address needs in the nuclear physics community for instrumenting large scale radiation detectors at relatively low cost, while still providing good time and energy resolution and digital capture of incoming waveforms.

The Pixie-32 is the first member of a family of digital spectrometers modules that will all share the same communication back-end while their front-ends have a variety of digitization and signal processing options to meet the community’s broad spectrum of readout electronics needs. This approach enhances the instrument’s flexibility because the front-end is easily adaptable to different experiments or applications.

The Pixie-32 is a 3U PXI Express (PXIe) card housed in a PXIe chassis. Its front panel high density connector can accept up to 32 single-ended analog signals. An optional 32 channel mezzanine board is under development that will expand the Pixie-32’s capacity to 64-channels. Output data transfer is via PCI express which, with suitable PC configuration, supports reading out multiple modules in parallel. Integration into larger systems is facilitated by front and back panel digital I/O that allow the Pixie-32 to generate and respond to various clock, trigger and veto signals.


  • 32 channel 12 bit 65 MSPS pulse processor
  • Synchronous multi-channel waveforms acquisition
  • Processor peaking times adjustable from 0.08 – 162 µs
  • Pile-up inspector and run statistics counters
  • Sub-nanosecond timing resolution
  • PXI Express platform: x4 link
  • Front and back panel digital I/O signals
  • Coming soon: on-board energy histogramming and pulse shape analysis parameters



Analog 32 or 64 preamplifier inputs, switchable input impedance:
50 Ω or 1 kΩ Impedance (factor installed)
Works with common resistive feedback preamplifiers of either signal polarity
Digital 10 digital inputs / ouputs for triggers or veto signals.
(Also configurable as 5 high speed differential signals.)

Backplane I/O

Clock Low skew system clock distributed to all modules
Digital Configurable LVTTL and LVDS lines for veto, run synchronization, multiplicity, and trigger distribution

PXI Express

Interface 3U CompactPCI form factor with x4 PCI Express interface
Data Transfer Rate Memory readout to host: 400 MByte/sec (sustained)
Parallel readout of modules with suitable chassis and PC
(e.g. a x16 host PC can read 4 modules in parallel)

Digital Controls

Gain On-board variable gain amplifier for flexible gain selection, +/- 10% digital adjustment
Offset -1.25 V to 1.25 V in 16384 steps by channel
Energy Filter Rise time and flat top: 0.08 – 162 µs
Acquisition Local and shared trigger, hit pattern, coincidence window
Data collection MCA limits and number of bins, waveform lengths

Data Outputs

MCA 1024 to 32,768 channels (32 bits deep) per Pixie channel
List Mode Energies, timestamps and waveforms
Statistics All values required for pileup correction are available: livetime, realtime, input events, output events
Diagnostics ADC trace, baseline distribution, baseline history