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920E 16-Input Multichannel Buffer

920E EtherNIM 16 Input Multichannel Buffer
  • 16-input, high-performance MCA in a two-wide NIM
  • Integral Ethernet connection for instant integration into CONNECTIONS spectroscopy networks
  • 16k-channel data memory, 231–1 counts per channel
  • 4k-channel ADC (15-µs fixed conversion time)

The ORTEC Model 920E is a member of the EtherNIM family of multichannel buffers. Combined with appropriate computer hardware, ORTEC signal-processing electronics, and ORTEC CONNEC­TIONS applications software, EtherNIM multichannel buffers are the ideal data acquisition hardware for a wide variety of applications in pulse-amplitude spectrometry. The 920E, a two-wide NIM, accommodates up to 16 inputs, with independent start/stop/ preset control. The unique “dynamic routing” feature enhances flexibility.
  • Literature +

  • More Information +

    The Model 920E provides the following functions:
    • High-speed multiplexer/router with 16 inputs
    • 4k-channel, successive-approx­imation ADC, with fixed conversion time of <15 µs; memory divisible into 1, 2, 4, 8, or 16 segments; memory size selectable as 1024, 2048, 4096, or 16384 channels. Connection between physical input and memory segment allocated under software control (“dynamic routing”).
    • Nonvolatile memory; 16k channels, 231–1 counts per channel

    The 920E is readily connected into an Ethernet environment. It may be inte­grated easily into existing networks. Control and spectral display is achieved by using a suitable ORTEC CONNECTIONS applica­tions package such as MAESTRO, AlphaVision, or Renaissance.

    The 920E employs a dual Direct Memory Access (DMA) architecture to maximize system throughput. The unique “dynamic routing” feature allows any one, or any group of inputs to be routed to any memory segment. This has many applications in areas as diverse as whole-body counting and fuel-pin scanning.

    The communications protocol used by the 920E is the “traditional” NIM digital bus NIM/4881 per DOE/ER-0457T (formerly NIM-GPIB) protocol used for several years in all ORTEC MCB products.2

    For the “Do it yourself” program­mer, a software toolkit is available to simplify the task of making a user-written application communi­cate with the Model 920E.

    1Please refer to “Standard NIM Digital Bus (NIM/488),” DOE/ER-0457T, U.S. NIM committee, May 1990; Standard NIM Instrumentation System, NTIS, U.S. Department of Commerce, Springfield, Virginia 22161.

    2The 920E also provides the ORTEC Dual-Port Memory connector on the rear panel. DPM communications are still supported by ORTEC applications packages for historical reasons, but Ethernet communications are recommended in most cases, for convenience (especially over large distances) and for ease and reduced cost of implementation. An RS-232-C port is also provided for diagnostic purposes.
  • Specifications +

    Successive-Approximation type with sliding scale linearization.
    Maximum Resolution 4096 channels, software selectable indepen­dently for each segment as 64, 128, 256, 512, 1024, 2048, and 4096.
    Digital Offset Independent for each segment in increments of 1 channel from 0 to 4096.
    Conversion Time Per Event 15 µs (fixed).
    Integral Nonlinearity ≤±0.025% over top 97% of dynamic range.
    Differential Nonlinearity ≤±1% over top 97% of dynamic range.
    Gain Instability <50 ppm/°C.
    Dead Time Correction Extended Live-Time correction according to Gedcke-hale method.
    Data Memory 16k channels of nonvolatile memory; 231–1 counts per channel (over 2 billion).

    Real Time/Live Time Multiples of 20 ms.
    Region of Interest Peak count/integral count.
    Data Overflow Terminates acquisition when any channel exceeds 2 billion.
    Peak Uncertainty
    Nuclide MDA

    Inputs One to 16, software selectable.
    Signal Isolation Typically >72 db rejection of unselected inputs.
    Input Threshold Set by front-panel screwdriver adjustment. Range is from 100 to 500 mV and is common to all inputs.
    Gain Nominally unity.
    DC Level Instability ≤20 µV/°C.
    Integral Linearity 0.05%.
    Gain Instability 50 ppm/°C.

    Front Panel Indicators
    CPU Busy
    Red LED’s intensity indicates the relative activity of the microprocessor.
    MUX Busy Red LED’s intensity indicates the relative activity of the multiplexer/router.
    ADC Busy Red LED flashes once for each pulse digitized by ADC.

    MUX Disc
    Screwdriver potentiometer from 100 to 500 mV.
    ADC Zero Screwdriver potentiometer adjusts the ADC zero offset ±250 mV.
    Screwdriver potentiometer adjusts the lower level discriminator from 0 to 50% of full scale.

    Input 1 Front-panel BNC accepts positive unipolar, positive gated integrator, or positive-leading bipolar, +10 V, pulse; +12 V maximum; semi-Gaussian-shaped or gated-integrator-shaped time constants of 0.50 to 30 µs. Zin = 1000 Ω, dc-coupled. No internal delay.
    Amplifier Inputs Accepts positive unipolar, positive gated integrator, or positive-leading bipolar +10 V; +12 V maximum; semi-Gaussian-shaped or gated-integrator-shaped time constants of 0.50 to 30 µs. Zin = 1000 Ω, dc-coupled. No internal delay. Inputs 1 to 16 are on rear-panel, 50-pin Amplifier Input connector. Optional cable (920-16-OPT1) converts 50-pin D connector to multiple BNCs.
    ADC Gate Optional, slow positive NIM input. Computer-selectable Coincidence or Anticoincidence. Signal must occur prior to and extend 0.5 µs beyond peak of input pulse. Front-panel BNC connector. Gate control for all active inputs.

    Ethernet Rear-panel BNC connector, accepts IEEE 802.3 10BASE2 (thin-wire coax).

    Electrical and Mechanical
    Power Required +24 V, 165 mA; –24 V, 165 m A. +12 V, 160 mA; –12 V, 110 mA;  +6 V, 1.2 A.
    Weight Net  2.25 kg (5 lb).  Shipping  3.1 kg (7 lb).
    Dimensions NIM-standard double-width 6.90 X 22.13 cm (2.70 X 8.714 in.) front panel per DOE/ER-0457T.
  • Ordering Information +

    Model Description
    920E 920-16 EtherNIM Multichannel Buffer with 16 detector inputs
    920-16-OPT1 Optional cable to convert 50-pin D connector to multiple BNCs for Model 920E