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To meet the requirements of thermoionization mass spectrometry (TIMS) for the determination of low-abundance isotopes，it is necessary to configure a secondary electron multiplier (SEM) or Daly detector ion counting detector on the TIMS. Compared to SEM，Daly offers high gain，low noise， good linearity，long service life, and the photomultiplier tube is located outside the instrument’s vacuum system and easy to replace，making it more cost-effective. The authors developed Daly detector consists of a detection chamber，an ion conversion pole，a plastic scintillator，a fast-response photomultiplier tube，a preamplifier，a single-photon counter，a power supply，and the measurement and control software. The response gating of the Daly detector can be adjusted between 0.1~2 V，the photomultiplier tube has a high voltage of 800~900 V，the ion counting background is less than 0.1 cps，and the highest count rate is 40 Mcps. In this paper，the performance of the Daly detector was verified by uranium isotope composition determination, and the results showed that the intra-test precision of Daly for the CRM0002 isotope abundance of 235U/238U was 0.073 %，and the intra-test precision of the isotope abundance of UTB500 was 0.139 %，0.056 % and 0.214 % respectively for 234U /238U，235U /238U and 236U /238U，which met the requirements of ASTM C1625—19.
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| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |
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