Compensation for Gamma background is crucial in tritium measurement, since a gamma field of 1mR/Hr will generate 500 times the ionization generated in 1µCi/m³ of tritium. Tyne designed the four, 250 cc ion –chambers in a cruciform with each chamber connected to an ultra sensitive electrometer amplifier and filter. All signals pass through the ADC converter, and the micro-processor calculates and displays the tritium value. To cover high ranges of tritium a separate small ion chamber is used. Measurements such as flow from the solid-state flowmeter and chamber temperature are also monitored by the micro-processor. 对γ背景的补偿是氚测量的关键,因为1 mR/HR的伽玛场产生的电离量是1 mI/m氚电离的500倍。TYNE设计了四,250毫升离子室在一个十字形,每个室连接到一个超灵敏的静电计放大器和滤波器。所有信号通过ADC转换器,微处理器计算并显示氚值.为了覆盖高范围的氚,使用了一个单独的小离子室。测量结果,如来自固态流量计的流量和室内温度,也由微处理器进行监测。
Specifications
Sensitivity | 1µCi/m³ ( 0.05 DAC) |
Accuracy | ±3µCi/m³ from 1 to 100µCi/m³, ±10% from 100µCi/m³ to 20,000 µCi/m³ |
Range | 1 µCi/m³ to 199,999 µCi/m³ |
Detector | 4 matched chambers – Two for measuring, two for compensation |
Measuring chamber effective volume | 500 cc (2 measuring chambers of 250cc each) |
Flow rate | 1.0 L/m |
Zero stability | ±1µCi/m³ immediately after unit is powered on |
Background cancellation | Less than 10% of the reading change in 20 mR/hr field |
Radon compensation | Included in the software |
Ion trap | Built into each ion chamber |
Dust filter | Built into the unit. |
Noble gas cancellation | Ports for air inlet/outlet of measuring chambers and compensation chambers are accessible on surface plate so silica gel drier can be placed between the chambers to compensate for presence of noble gas. |
Tritium Discrimination | Instrument can discriminate in a field of HTO and elemental H3 using the silica gel drier. |
Purge/Decontamination | All 4 Chambers can be heated up by a cartridge heater controlled by unit |
Display | Graphic touchscreen LCD display. Unit displays the values(tritium and Gamma) both in numerical format and graphical trend. |
Communication | Can be configured to RS232(Short distance) or RS485(Long distance). |
Analog output | 0-5 V Linear or logarithmic voltage output. |
Power supply | 2.5 V- 5V external power supply, or 3 C-cell battery. Total power consumption is 150mA. |
Gamma measurement | Gamma is measured directly by the unit. Gamma measuring range is from 0.1mR/h to 10R/h |
Alarm | Tritium alarms, gamma alarms, low air flow alarms will all be shown by red LED light and by an audible device. |
Data logging | The tritium and gamma values are logged every minute with current time and date stamp |
Size and weight | 8″(L)x5″(H)x5″(W), 7 lbs. |
Drier | Note that the silica gel drier is not part of the standard equipment, but can be supplied as an extra. |
Response Time | 30 seconds at 90% of signal |