FHT 770 R     Automatic Sample Changer

Features of a typical system:

• automatic measurement of 60 mm samples in batches of up to 60 units
• measuring range of alpha and beta gross activity: 1 Bq - 105 Bq
• sample changer transport mechanics with electric motor drive
• alpha measurement insensitive against ambient doserate
• 4pi shielding of detector and measuring position
• self control of the instrument
• integrated software for the evaluation of all countrates taking into consideration all statistically relevant criteria
• electronics FHT 8000
• internal signalisation of alarms and detector fail-rate

Sample Changer Mechanics FHT 770 R

• input and output magazine for up to 60 sample planchets with a diameter of 60 mm
• up to 3 measuring positions
• electric motor driven transport to measuring positions and to output magazine
• serial interface to FHT 8000
• internal PLC, motor drive and mains supply

Detector FHT 650 K1

The sample changer is fitted with a gas flow proportional counter tube FHT 650 K1. The efficiency values of the detector related to 4pi geometry (measured operation conditions, 60 mm planchet source) account to:

tolerance: ± 10%

• window diameter of detector: 60 mm
• area density of window: 0.3 mg/cm²
• counting gas: ArCH4 (90/10) gas flow

Measuring Electronics FHT 8000

For measurement and evaluation an electronics  FHT 8000 is used. It comprises all boards to supply the detectors, count the detector signals and to calculate the measured values. The operation is fully automatic not necessitating any further user intervention. All evaluation routines are stored as software modules and include control routines for the operational modes of the FHT 770 R.

• data acquisition and evaluation system with embedded PC-compatible computer
• external 15" VGA monitor
• protocol printer
• operating system MS-WINDOWS
• hard disk
• basic version with 16 counter channels
• software based configuration of measuring modules
  (amplifier thresholds, assignment of counter channels etc.)

Measuring Channel FHT 8000 - Software

The FHT 8000 includes all programme modules and functionalities for the fully automatic operation of the sample changer:

• start-up routines (setting of parameters)
• data acquisition and evaluation routines
• protocol generator for measurement results; data storage
• control of sample changer mechanics
• control of failrates and alarm levels
• plateau measurement
• background and calibration measurement
• automatic restart after power fail