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As the field verification standard for radioactive measuring instruments such as gamma loggers in uranium exploration work，radium sources have played a good role in controlling the metrological performance of the instruments. However，due to national security and environmental protection policies，the existing number of solid radium sources in China can hardly meet the increasing demand of uranium exploration workload，and there is an urgent need to carry out the development of alternative verification devices. It is planned to use natural uranium ore powder and other materials to develop verification devices to verify the radioactivity measuring instruments during the period. Based on the theory of γ radiation field，the relationship between the geometry of the verification device and the internal γ field was calculated，and it was experimentally verified that an annular column verification device with an internal bore diameter of 50 mm and an axial length of 600 mm can ensure that the center of the verification device has a saturated plateau area of 200 mm，leaving at least 100 mm redundancy for convenient detector placement. The internal irradiation volume rate is positively correlated with the thickness of the horizontally oriented ore layer before the saturation thickness is reached. The practical geometry of the γ logger verification device was determined by theoretical calculations，avoiding the waste of material and time in a large number of conservative designs.
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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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