ULLA

Advanced ultra-low background Triple-to-double coincidence ratio (TDCR) liquid scintillation counter with triple coincidence detection. Designed for precision measurements of low-level alpha and beta isotopes. Combines passive lead shielding and active guard with modern usability for demanding applications.

• Status: Active
• Country: Finland
• Isotopic: Yes
• Type of measurable elements: Radioactive isotopes
• Measurable isotopes/elements: ³H, ¹⁴C, ⁹⁰Sr/⁹⁰Y, ²²²Rn, ²²⁶Ra, gross alpha/beta
• Sensitivity : Quench correction using TDCR or external Eu-152 standard
• Background : <1 CPM (measured at Hidex facility)
• Detection type : Triple photomultiplier tube (PMT) detection with active guard
• Energy range : Low-energy beta and alpha isotopes typical of environmental samples
• Efficiency normal count Mode : ³H: >70%; ¹⁴C: >97% for unquenched samples; >35% for ³H in 8+12 mL H₂O
• Figure of Merit (FOM (E2/B) : ³H in 8+12 mL H₂O: >600 without optimization; >900 with DigitalPb optimization
• Observed performance : Low background of <1 CPM in normal surface lab conditions
• Alpha/beta separation : Yes, with unique 3D graphical calibration for reliable discrimination
• Sample capacity: 80 × 20 mL or 192 × 7/5 mL vials
• Gas supply: Nitrogen flushing available to remove radon gas
• Power Requirements and Consumption : Standard AC power supply; optional cooling modules for optimal temperature control
• Environmental requirements : Stable conditions with optional deionization of vials to remove static electricity
• Dimensions and Weight: 69 cm W × 130 cm H × 95 cm D (with cooler); Weight: ~800 kg