叠片法测量“闪光二号”加速器的高功率离子束能谱

给出了利用叠片法测量“闪光二号”加速器高功率离子束能谱的基本原理及初步实验结果. 采用Ziegler的拟合公式编制程序计算了不同能量质子和碳离子穿过不同厚度Mylar膜后的能 量损失情况.在偏压法拉第筒阵列各个法拉第筒的准直孔前分别覆盖0—6μm厚的Mylar膜， 根据不同膜厚对应的信号衰减情况(叠片法)，得到了高功率离子束的离子能谱，离子的最高 能量>440keV，平均能量约为270keV，能量为200—300keV之间的离子数目最多，碳离子数和 90keV以下的质子所占总离子数的组分不多于32％.所测量离子能谱和离子数目随时间的分布 关系与二极管的电压和电流符合也较好.还将叠片法的测量结果与利用磁谱仪和采用飞行时 间法等的测量结果进行了比较，三种方法所得的测量结果基本一致. 关键词： 高功率离子束 离子能谱 法拉第筒 叠片法 能量损失

Energy spectra of high-power ion beams measured with a pile of thin films on FLASH Ⅱ

The preliminary experimental results obtained for the energy spectra of high-power ion beam(HPIB) with a pile of thin films on FLASH Ⅱ accelerator are reported. Code was developed to calculate the theoretical energy-loss of proton and C ion beams transmited through the Mylar films with different thickness. T he apertures of Faraday Cups are covered with Mylar films of different thicknes s, and then the signal attenuations can be recorded with oscilloscope. The energ y spectra of HPIB and the diode voltage are obtained according to the signal al lenuations. The diode voltage measured with a pile of thin films agrees with the voltage measured with a differential ring. And the ion number versus time curv e was given. In addition, the ion energy of HPIB is also measured with Thomson spectrometer and time of flight method and the results agree with those measured with a pile of thin films.