The spatial resolution, dE/dx resolution and cell efficiency of two prototypes of small-cell drift chamber filled with He/C 3H 8(60/40) with cell sizes of 14.0mm and 16.4mm were measured using cosmic rays respectively.

• 利用宇宙线分别测量了两个单元尺寸为14mm和16.；4mm充He/C3H8(60/40)气体的小单元漂移室模型的性能；包括空间分辨；dE/dx分辨和单元效率。