- Powerful semi-custom configurations are quickly implemented to customer
specifications
- Simultaneous amplitude measurement and pulse shape analysis for each
channel.
- Pulse heights measured with up to 16 bits accuracy (i.e. 64K spectrum
length).
- 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
40 microseconds.
- 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
mode.
- 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
loop" applications.
HV Inhibit: TTL logic input. BNC connector, jumper set active
HI or LO.
- Interface:
USB: Universal Serial Bus 1.0
EPP: Enhanced Parallel Port, defined by IEEE specification
1284, standard.
OEM: Auxiliary 25 pin programmable bidirectional I/O connector
optionally available.
- 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
attenuation.
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
bin)
- Data Outputs (via USB or EPP Port)
Spectrum: 1024-65536 channels standard, more with optional
extra memory.
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 Polaris 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
available.
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;
+/-12V Analog@50mA
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
of order.
- Dimensions: 8.450"" W x 6.0" D x 0.75"
H.
- Weight: net 0.5 lbs.; shipping 2.0 lbs.
- Manual: Hardware and software manuals provided with each
instrument.
- Software: The Polaris comes with all necessary software and
firmware included:
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
microseconds
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.
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