钼靶X射线参考野均匀性测量及剂量分布研究

摘要

The two-dimensional ion chamber matrix method and thimble ionization chamber scanning method are respectively used to measure the radiation field of X rays.The former can quickly measure radiation field, realize X-ray primary beam, aperture, shutter, filter, positioning device coaxial adjustment.The later is more accurate and reliable because of its consistency in scanning the uniform area of the radiation field point by point.When it is 1m away from the molybdenum target spot, the thimble ionization chamber can have a hori-zontal direction uniformity better than 95%with the radiation field size of about 124 mm,a vertical uniformity better than 95%with the radiation field size of about 103 mm, meeting the molybdenum target X-ray bench-mark establishment and quantity transmission requirements.%采用二维电离室矩阵法和指形电离室扫描法测量X射线辐射场均匀野。二维电离室矩阵法快速、简便，可实现X射线主射束、光阑、快门、过滤片、定位装置同轴的调整。指形电离室逐点扫描法测量辐射野均匀区，具有一致性好，结果准确可靠之特点。距钼靶焦斑1m处，指型电离室测得水平方向均匀性好于95％的辐射野尺寸约为124 mm。竖直方向均匀性好于95％的辐射野尺寸约为103 mm。满足钼靶X射线基准建立和量值传递要求。