[en] The model QF1105 low noise charge sensitive preamplifier using for coaxial Ge(Li) detector is described. The noise level is less than or equal to 700 eV (Ge) (typical value is 603 eV) with a capacitance of zero pF and degrades at less than or equal to 15 eV/pF

[en] It introduced the design ideas, the technical specifications and major performance for Model BH1217G-the latest Ultra-low Background Alpha Counting Measurement System, and gave the measured result of the actual samples. This system is chiefly used to monitor the personal inner irradiation situation which people worked in radioactive environments by checked their urine, and also can measure low level ALPHA radioactivity. (authors)

[en] Design, adjustment and performance of Ge(Li) detector with cooled charge sensitive preamplifier are introduced. It can conveniently be used together with anticoincidence ring detector

[en] Model BH1217B double channel measuring instrument for monitoring weak α and β radiation with large area semiconductor detector are described. In case of 2π detection efficiency ≥85% (typical value 90%) for ²³⁹Pu with typical background of 0.015 cm^-2·h^-1 and ≥40% (typical value 50%) for ⁹⁰Sr-⁹⁰Y with typical background of 0.03 cm^-2·h^-1. Counting efficiency for α entering β channel: <1%, and for β entering α channel: 0. Data collection, control and processing are all completed by computer

[en] A newly developed Model BH1217B double channel measuring instrument with large area semiconductor detector for monitoring low level α β radiation has been described. For ²³⁹Pu α source, in case of 2π detection, efficiency ratio ≥90% (typical value 98%), background ≤0.0008/cm²·min(typical value 0.0001/cm²·min). For ⁹⁰Sr-⁹⁰Y β source, in case of 2π detection efficiency ratio ≥45% (typical value 60%), background ≤0.008/cm²·min (typical value 0.03/cm²·min). Counting efficiency for α entering β channel: ≤1% (typical value 0.2%), and for β entering α channel: 0. Data collection, data control and data processing are all completed by computer

[en] This paper introduces the latest development of intelligent low background Alpha-Beta Counting System, including the whole design idea, main characteristics and various performance indicators of the measurements. The actual technical indexes of the experimental prototype and the experimental results are given. The intelligence low background Alpha-Beta measurement instrument has good performance, the Alpha background per hour is less than a background count (≤ 1 count/h). The instrument has achieved the miniaturization, integration, modularization, and has the characteristics capable of multi task independent operation. The main application of this instrument to measured the weak Alpha-Beta radioactive. (authors)