DGF instruments accept inputs directly from detectors generating exponentially decaying pulses. Examples include HPGe detectors with RC feedback preamps and scintillators with PMTs. The signals are conditioned for analog gain and offset and digitized at the ADC sampling rate (75 MHz to 500 MHz).
The digitized data streams are subjected to first level digital processing at the real time processing units (RTPUs) implemented in field-programmable gate arrays (FPGA's). The RTPUs detect the leading edge of a pulse, process the signal for pulse height measurements and capture digital waveforms in First-In-First-Out (FIFO) memories. Preprocessed event data are passed on to an on-board digital signal processor (DSP). The DSP executes a second level of digital signal processing (2LDSP) on the event data, including acceptance decisions and MCA histogramming.
Accepted events are time stamped, which is useful for event identification and measuring times between events. Being performed only for accepted events, 2LDSP can be much more comprehensive than the RTPU processing. For example, sophisticated pulse shape analyses can be performed and only extracted values sent to the final storage on a PC's hard drive.
The DGF's distributed parallel digital processing architecture thereby facilitates much higher event rates, at significantly lower costs, than could previously be achieved using strictly analog instrumentation.
The DGF family of instruments can be customized
for OEM customers. Click here for a detailed summary of differences between the Pixie modules.
The microDGF is a variant of the highly
successful microDXP, with the analog front end and ADC upgraded specifically
for high resolution gamma spectroscopy.
The Pixie-Net is a multi-channel digital spectrometer
for radiation detectors in desktop format with integrated networking and USB resources.
Pixie-4 Express Modules are PXIe (Compact
PCI Express) 3U standard modules comprising 4 high speed DGF channels.
Pixie-16 Modules are PXI (Compact
PCI) 6U standard modules comprising 16 integrated DGF channels.
Pixie-4 Modules are PXI (Compact
PCI) 3U standard modules comprising 4 integrated DGF channels.
This product is obsolete. We recommend the Pixie-4 Express for new customers.
Pixie-500 Express Modules are PXIe (Compact
PCI Express) 3U standard modules comprising 4 high speed DGF channels. This product is obsolete. We recommend the Pixie-4 Express for new customers.
Further online information:
- The DGF software
page contains description of the host applications and drivers
available from XIA.
- The support
page describes common problems and solutions