MDS Alpha/Beta Counting Multi-Detector System

The Multi-Detector System (MDS) is a multi-detector, low-background system for low-level background alpha and beta counting. The MDS is a premium system available for applications requiring high sample throughput and high sensitivity.

  • Independent Sample Drawers
  • Independent Sample Detectors
  • Zero Adjacent Detector Crosstalk
  • Reliable Communications Protocol
  • Full Frontal Easy Service Access
  • Complete Modularity
  • Parallel Gas Distribution
  • GasPRO™ Flow Sensing
  • Dead-time Corrected Count Timer
  • Field Expandable
    • Supports from 4 up to 48 detectors
    • Modular design for enhanced flexibility using multiple MPC-9604 units
  • Lowest Backgrounds in the Industry
    • Four Inch 4π Virgin Lead Shield
    • Cosmic Guard Detectors
    • Selected Low Background Materials
    • Linear Low Voltage Power Supplies
  • Vista 2000 Comprehensive Software
    • MS Access™ Database (Non-relational) Intuitive Database Navigation
    • Sample and Source Logs
    • QC Control Charts
    • Linked Count and Calibration Methods
    • Count Presets or Count to MDA
    • Standard and Custom Reports
  • Literature +

  • Specifications +

    Counting Performance
    Each MPC-9604 contains four independent 2.25 inch diameter pancake style gas flow proportional sample detectors and a large area gas flow proportional cosmic guard detector. Each sample detector has a field replaceable (low cost) aluminized window with a nominal density of 100 µg/cm2, 1 sample carrier with inserts for 1/8 inch, 1/4 inch, and 5/16 inch planchets per detector (planchets are not included). Each of the four channels of a MPC-9604 exhibits the following performance specifications.

    Alpha Beta
    Background Typical 0.03 - 0.07 cpm 0.4 - 0.7 cpm
    Warranted ≤0.1 cpm ≤0.9 cpm 

    (Background values are dependent on environment and altitude. Warranted values are as measured at factory undercontrolled conditions.)

    Alpha Beta
    Efficiency Typical Po210 40% Sr90/Y90 55%
    Am241 40% Cs137 40%
    Th230 40% Tc99 35%

    (Efficiencies are typical values; energy and geometry dependent; as measured at factory under optimized conditions with factory specified sources; and, measured using P-10 counting gas.)

    Alpha Beta
    Plateau Slope <1.5%/10V <2.5%/100V
    Length >1000 volts >200 volts

    (Plateau measurements use point sources at optimum geometry using P-10 counting gas. Alpha plateaus use Po210: beta plateaus use Sr90/Y90)

      Alpha to Beta Beta to Alpha
    Crosstalk Instrument Induced <0.1% <0.1%
    Naturally Occuring Source Dependent Source Dependent

    Detector Uniformity >95% over active area
    Dead Time Correction Tested to 300,000 counts per minute with <1.5% dead time loss for each detector channel simultaneously and independently
    Count Modes Alpha only or simultaneous alpha + beta


    Gas-PRO Failsafe P-10 monitoring system senses breaches in flow
    Gas Flow Nominally set to 60 cc/min with a critical flow orifice. Each unit includes a rotameter style flow meter and a parallel feed gas distribution manifold for the counting gas. Nominal inlet pressure 10 psi (15 psi recommended maximum).
    Shield 4" (10 cm) thick selected virgin lead
    Dimensions 32" W x 16" D x 16" H ( 81.3 cm W x 41 cm D x 41 cm H)
    Weight Installed 1200 lbs (545.5 kg)    Shipping 1400 lbs (637 kg)
    AC Power 117 V ac, <1.7 A, 50/60 Hz; 230 V ac, <0.9 A, 50/60 Hz
    Environment 10 - 40º C; 20–90%, humidity, non-condensing
  • Ordering Information +

    MDS systems are designated as -4, -8, -12, or -16, depending upon the total number of detectors. All MDS-XX systems will include one MPC-9604 unit per four detectors; gas line fittings and tubing, and two-stage gas tank regulators† (one per 8 detectors). Systems supplied to the U.S. domestic markets include a factory supplied PC including a Microsoft Windows operating system, Vista 2000 control software, a laser printer, and installation. Export systems include a locally supplied PC and printer with installation provided by the nearest authorized representative. Vista 2000 requires a computer running Microsoft Windows 2000 or Windows XP as a minimum. The computer must have a native RS-232-C interface (converted USB ports will not work).

    †Tank regulators use a US standard tank thread (CGA-350 .825”-14NGO-LH-EXT) and may require adapters not supplied byORTEC.

    MDS System Configuration

      MDS4 MDS8 MDS12 MDS16
    MPC-9604 1 2 3 4
    MDS-CTRL* 1 1 1 2
    Additional Gas Regulator N/A N/A 1 N/A

    *Includes VISTA 2000, RS232/485 interface, null modem cable, and one gas regulator.


    MPC-9604 Self-contained four-detector unit to add counting capacity to an existing MDS system
    MDS-RACK Heavy duty rack assembly to hold two MPC-9604 units
    ACC-02 Wheeled cart holding one MPC-9604 unit