The DGF Pixie-4 Express (Pixie-4e) is a multichannel data acquisition system for fast radiation detectors in nuclear physics and other applications requiring coincident radiation detection. It provides digital spectrometry and waveform acquisition for four input signals per module; several modules can be combined into a larger system. The DGF Pixie-4e is based on the CompactPCI/PXI Express standard which allows data transfer rates from Pixie-4e memory to the host computer of several hundred MB/s. In a suitable PXI Express chassis, multiple modules can be read out in parallel. Commercial CompactPCI or CompactPCI Express modules - DSP processor boards, HV supplies, embedded host computers - can be added to build a flexible standalone data acquisition and analysis system.
Each of the four channels of a Pixie-4e module accepts signals directly from a detector preamplifier or photomultiplier tube. After a digitally controlled gain and offset stage, signals are digitized in a 12-16 bit ADC at a rate of 125-500MHz. Triggering, pile-up inspection and filtering of the data stream is performed in real time; pulse heights and other event data is calculated on an event-by event basis. Results are stored in 32K of spectrum memory per channel and 256MB of list mode memory organized as a FIFO.
- 125-500MHz, 12-16 bit digitizing of input signal. Standard configurations: 125MHz/16-bit, 500MHz/14-bit, 125MHz/12-bit
- x4 PCI Express interface with module-to-host transfer rates of several hundred MB/s (interrupt driven DMA)
- Simultaneous amplitude measurement and pulse shape analysis for each channel
- Pulse heights measured with up to 16 bits accuracy on each of the four channels
- Waveform acquisition up to 4K samples for each channel (8-32 us)
- 32K x 32bit on-board spectrum memory for each channel
- 256 MB on-board FIFO memory for list mode data
- Programmable gain, input offset, trigger and energy filter parameters