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The Pixie-16 can operated through XIAs host control software or by integrating C libraries into existing user acquisition software. Users can set all parameters relevant to the data acquisition, store them in settings files, and run the modules. Results can be displayed from data files to provide instant feedback on the state of the experiment.
XIA’s host control software provides several diagnostic tools for setting up a new system. There is a display of triggered and untriggered waveforms as they are seen by the Pixie module. The waveforms can also be subjected to a fast Fourier transformation (FFT). These displays are useful to investigate if there is any electromagnetic interference in the system, from 50/60Hz to radio-frequency pickup. For system setup, users can employ automated tools to determine the decay time of the preamplifier and to set the offset to a specified fraction of the dynamic range.
Experiments that run their own data acquisition software can use XIA’s driver (written in C) to integrate Pixie modules into their system. Module setup, start and stop of runs, and data readout can be performed using a small number of functions. The Pixie Viewer is based on the same driver and can be used as a programming example.
A basic data acquisition system can consist of an 8-slot PXI crate with integrated preamp power supplies, one Pixie module, a single board host computer and a high voltage module. The host computer is used to download software and settings to the Pixie module, start and stop runs, read out the data and write it to disk.
Instead of a single board computer residing in the PXI crate, a regular desktop or laptop computer can act as a remote crate controller using a set of adapter cards with a high speed copper or fiber optic data link. Data readout speeds are equivalent for local and remote controllers.
For bigger detector arrays, a larger PXI crate (up to 14 slots) can be used. One or more slots can be occupied by commercial, user-programmable DSP processor modules to process data for event reconstruction. High speed I/O modules can be added, either on the DSP modules or in a separate slot, for fast data readout from the Pixie front end electronics to external data processing computers.
inputs, switchable input impedance and attenuation:
Each module has
a 4 LVDS inputs/outputs and 12 TTL (3.3V) inputs and outputs These can
be programmed to be used for functions such as:
|Data I/O||Interface||Compact PCI standard, 33 MHz, 32-bit|
|Data Transfer Rate||Memory readout to host: 109 MB/sec|
|Digital Controls||Gain||Fixed voltage gain set to user specification, digital gain adjustement +/- 10%.|
|Threshold||Adjustable to 50% of the ADC input range|
|Filtering||Peaking times 0.1 - 50 microseconds. Adjustable flat top to eliminate ballistic deficit effects.|
|Pileup||Fast channel filter
time, pulse detection threshold, and fast channel pileup inspection test
limits may be set independently to achieve best results in every gamma-ray
Minimum pulse-pair resolution of 40ns unless limited by signal risetime.
|Data collection||MCA limits and number of bins, waveform lengths|
||MCA||1024 to 32,768 channels
(32 bits deep) per Pixie channel
|List Mode||Time stamp, energy, optional waveforms for each eventStored in 128k (16-bit) Fifo for uninterrupted data acquisition|
|Timing||Events are time stamped with 75MHz clock in list mode.|
|Statistics||All values required for pileup correction are available: livetime, realtime, input events, output events.|
|Diagnostics||ADC trace, baseline distribution, baseline history, FFT noise spectrum|
XIA Home > Products > DGF Products > DGF Pixie-16
http://www.xia.com/DGF_Pixie-16.html, last updated
January 28, 2013