- Powerful semi-custom configurations are quickly implemented to customer
- Simultaneous amplitude measurement and pulse shape analysis for each
- Pulse heights measured with up to 16 bits accuracy (i.e. 64K spectrum
- Dead times as low as 1 microsecond per event are achievable (limited
by DSP algorithm complexity). Events at even shorter time intervals
can be extracted via off-line ADC wave form analysis.
- Digital constant fraction algorithm measures event arrival times down
to a few ns accuracy .
- Programmable gain, input offset, and peaking times between 0.25 and
- Programmable pileup inspection criteria include trigger filter parameters,
threshold, and rejection criteria.
- Supports multiparametric data acquisition of events distributed over
many detectors as well as independent spectrum acquisition.
- Waveform capture up to 100 microseconds in length for each channel.
- On-board MCA memory for data taking or for monitoring when in multiparametric
- Signal Input (Analog) - Works with common reset or resistor
feedback preamps of either polarity.
Impedance: 50 Ohms, 90 Ohms,
250 Ohms, and 1k Ohms
- jumper selectable
Attenuation: 1:21, 1:12, 1:5 and 1:1- jumper selectable
Voltage Range: +10.0 V to -10.0 V standard
- Inputs (Digital)
Gate Input: Analog input for Compton suppression. Can alternatively
be configured as digital I/O.
Sync Input: (Special Order) TTL logic input to control time
resolved data collection, including scanning and "phase locked
HV Inhibit: TTL logic input. BNC connector, jumper set active
HI or LO.
USB: Universal Serial Bus 1.0
EPP: Enhanced Parallel Port, defined by IEEE specification
OEM: Auxiliary 25 pin programmable bidirectional I/O connector
- Digital Controls (Set via EPP Port)
Gain: 50X coarse gain (2% accuracy), fine gain controlled by
16 bit DAC.
Dynamic Range: 5MeV for preamp gains of 100mV/MeV; more with
Shaping: Triangular/Trapezoidal. Peaking time and dwell set
independently : 50ns - 45 microseconds in small steps. Adjustable
dwell time may be used to eliminate ballistic deficit effects.
Pileup: Set fast channel filter time, pulse detection threshold,
and fast channel pileup inspection test limits to achieve best results
in each situation.
Spectrum: 1K-64K bins, 32 bits deep (4.3 billion counts per
- Data Outputs (via USB or EPP Port)
Spectrum: 1024-65536 channels standard, more with optional
Other: Collection livetime; Event-by-event waveforms; input/output
count rates; Compton coincidence rate
- Control Outputs (TTL via OEM Port)
Control Signals: sends or receives TTL control signals via
optional OEM connector, to create flexible custom interfaces to external
instruments or industrial equipment. Lets custom DSP codes integrate
the DGF-OEM into dedicated spectroscopy applications.
- Power Outputs
Detector Supply: High Voltage +/- 5kV, SHV connector, push-button
on/off, front panel adjust, 60 sec. on/off ramp standard . Other options
Preamp Supply: standard preamp power voltages +/- 24V and +/-
12V, each to 100 mA.
- Power Requirements:
DC Voltages: +5V Digital@250mA; +5V Analog@250mA; -5V Analog@100mA;
Line Voltage Requirements (w/ power supply option):
110 V at 0.2 A 50/60Hz or 220 V at 0.1 A 50/60Hz, specify at time
- Dimensions: 8.450"" W x 6.0" D x 0.75"
- Weight: net 0.5 lbs.; shipping 2.0 lbs.
- Manual: Hardware and software manuals provided with each
- Software: The DGF-OEM comes with all necessary software and
FiPPI and DSP firmware, version dependent on application
Polaris Viewer host control software
C libraries for OEM applications also available
- Energy resolution: Comparable to best analog units. DE degradation
at high count rates is typically dominated by imperfect pole/zero
cancellation in the preamplifier.
- Dead time:
Filter dead time: (2 * peaking time + flat top time)
Additional dead time due to DSP data reading, for the typical case
of reading pulse height data and 32-point traces for N channels, 1
<= N <= 4: 1.7 microseconds + N * 3.0 microseconds
- peaking time.
- Event processing time:
Basic pulse height reconstruction (dE/E = 0.25%, FWHM): 1.0
microseconds + N * 3.6 microseconds
Pulse shape analysis for improved energy resolution: adds N*2.75
Pulse shape analysis for CFD timing: adds N*2.00 microseconds
Histogram to DSP memory: adds 0.35 microseconds
+ N*1.40 microseconds
The last three operations can be set on a channel-by-channel basis.
Event raw data acquisition is done in a DSP interrupt routine and
can interrupt event processing, which resumes afterwards.
- Data acquisition:
Spectra: 64K words of spectrum memory. Lower limits for spectrum
entries and bin widths are programmable.
Waveform record: lengths from 0 - 102.4 microseconds for local
processing, or export to host.
Statistics: records run duration, event rate and both live
time and input rate.
Note: The following quantities are from a particular
detector (an Ortec Iglet-x) and may vary some-what for other detectors
- Count rate precision: 0.1%, or limited by statistics
- Peak stability with rate: 0.05% up to highest ICR.
- Integral Nonlinearity of Energy: = 0.1% of full scale.