Detector sensitive area*
            1000 cm2
            28cm (11”) depth x 35.5cm (14”) width
            Chamber entrance height = 2.2cm (.875") tall
            * Standard size. Detector can be scaled based on customer requirements.

   Detector Type
           Gas Flow Proportional

   Gas Used
            P-10 Nuclear Counting Gas
            90% Argon, 10% Methane
            (DOT Class 2.2 Nonflammable Gas)

   Background
            Less than 5 alphas/hour (0.005 alphas/cm2/hr)

   Detection Efficiency
            Greater than 80% (2 pi )

   Operating Voltage
            + 800 VDC

   Alpha Detector Window
            250 µg/cm2 metalized Mylar

   Overall Outside Dimensions
            46cm (18”) wide x 55cm (21.5”) deep
            11.4cm (4.5”) tall

   Weight
            7 kg  (15 lbs.)

   Electronics
            Detector Bias Power Supply, 1Kv
            On board Charge Sensitive Pre-amp, Linear Amplifier, Integral Discriminator,
            PC Mounted Data Acquisition Hardware.

   Gas Handling
            Dual Stage Gas Regulator
            Adjustable Flow Controller

   Pricing and Delivery
        Please contact us for current pricing and delivery schedules.
 

For almost 20 years, the staff at Alpha Sciences Inc. has been providing low background alpha counting systems used as an industry standard to determine trace contamination of alpha particle emitting radionuclides found in IC process materials. Our original model, the 1850, has been upgraded with PC based acquisition features, making the tool more effective in analyzing data, while maintaining those features that make it easy to use and reliable. This new offering is called the Model 1950.

The Model 1950 Ultra Low Background Counting System is comprised of three main component sections:

1. An ultra low background gas flow proportional counter with Radon blocker;
2. A P.C. based data acquisition system;
3. A dual stage gas regulator with gas flow controller.
 

ABOUT THE DETECTOR

The detector consists of two chambers separated by an extremely thin Mylar film (window) which is about 2 microns (250mg/cm2) thick. The detector
chamber has a special P-10 nuclear counting gas which flows through the detector at a very low flow rate. The sample chamber contains the sample tray,
which positions the sample close to the Mylar window. As alpha particles are emitted from the sample, they pass through the Mylar window and ionize the
P-10 gas in the detector chamber. These alpha particle ionization tracks in the detector are sensed, amplified, discriminated, and then counted for a
predetermined period of time.
 

HOST P.C. and ELECTRONICS

The electronics portion consists of two sections. The analog section includes a charge sensitive preamplifier, the detector bias power supply, an amplifier, and
a discriminator (set for 1 MeV). This analog electronics module is attached to the back plate of the detector housing , and derives its power from the system
host P.C.

A scaler / timer board is the second electronic section and is housed within the P.C. casing. The alpha particle generated signals from the detector are
amplified and discriminated, and then routed to the scaler / timer board which serves as an accumulator. The user programs the P.C. for a selected data
acquisition period (dwell time) and this data is displayed on the monitor as a time histogram. The histogram is in graphical representation, wherein the
horizontal axis represents time intervals, and the vertical represents the alpha count value for that specific time interval.
 

WORKING WITH RESULTS

At the conclusion of the user configured total acquisition time, the user may define the "Region Of Interest” or ROI by using simple point and click
commands. The alpha counting program then automatically calculates the integral for the total count period, removes the established background from the
value, and then divides then result by the defined sample area. Finally, a correction factor is applied to adjust data based on detector counting efficiency. The
display then provides the corrected data for net alphas per centimeter squared per hour. The data is then available for a print out should the user wish a
permanent hard copy or record.

SYSTEMS AND SERVICE

For both heavy end use and occasional sample counting, Ultra Low Background Alpha Counting Systems and Services are available from Alpha Sciences Inc. Complete systems are available which include NIST traceable calibrated detectors and discounts on future software upgrades. Sample counting services in our labs using the Model 1950 are available for a wide range of sample materials, from pastes and powders, to sheet and mold forms. Please contact us for our current system and service pricing.