GB-Bristol: Ion Chambers

Description

The Chemical, Biological, Radiological and Nuclear (CBRN) Delivery Team (DT) has a requirement to procure quantity seven 1000cc spherical ion chambers to support tertiary level calibration of Radiation Detection and Monitoring Equipment (RDME) used within the Ministry of Defence (MoD). The authority currently uses the Unidos electrometer model type 10002, therefore the ion chambers required must be compatible for use with this instrument. The chambers must meet the following specifications: 1. Ion Chamber Type: Guarded (Air Equivalent) Vented. 2. Connector Type: TNC (Male) 3. Volume: 1000cc 4. Sensitivity: ≥40 µC/Gy 5. Collection Efficiency: ≥99% 6. Mounting: Rigid Stem 7. Measurement Range: ≤0.1mSv/h to ≥0.3Sv/h 8. Energy Range: 40 keV to 1.3 MeV (≤±4% across the range) 9. Directional Dependence: ≤+0.5% (for rotation around the chamber axis - ≤±5% (for tilting the axis up to ±45 degrees) 10. Short Term Stability: Readings taken within 2 hours after warm-up shall be within ±0.5% of those taken directly after warm-up 11. Long Term Stability: Readings taken over a prolonged period of operation shall be within ±1% of those taken directly after warm-up 12. Post Irradiation Leakage: Signal to drop to 1% within 5s after irradiation. 13. Leakage Current: ≤10fA 14. Maximum Bias Voltage: 500V (positive / negative potential) Nominal +/-400V 15. Polarity Effect ≤±1% 16. Extension Cable: 10m (TNC Female to TNC Male) 17. Cable Leakage: ≤1pC/(Gy.cm) Each ion chamber must be accompanied with a check source and fixture to enable a geometrically reproducible location of the source. The Contractor shall be responsible for: 1. The manufacturer of seven identical 1000cc ion chambers. 2. The delivery of the chambers.