一种二进制降能器设计方法

A method of designing binary energy degrader

为提升在中国原子能科学研究院的100 MeV质子回旋加速器上进行多能点质子单粒子效应实验的效率,针对该加速器提供的100 MeV质子设计了一种二进制降能器.降能器包括6片铝降能片,厚度分别为0.5,1,2,4,8,16,32 mm,即后一片厚度均为前一片的2倍.提出相对厚度的概念,此概念也可用来表示产生的质子能点的次序以及降能器的状态或操作.降能器产生的9.69 MeV以上的61个质子能点间隔在0.84—4.09 MeV之间,且能量岐离均在10%以下,散射角半高宽均在45 mrad以下,基本可满足质子单粒子效应实验的要求.对加速器直接提供的质子的能量精度对降能器产生的质子能点的影响进行分析,发现经降能器产生的质子能量越低,其影响也就越大.此外,降能器对加速器直接能够提供的70—100 MeV能区的质子也是适用的,且可通过增加降能片数量的方式来获得更加连续化的质子能点.本文提出的降能器设计方法简单有效,具有较强的借鉴价值.

In order to improve the efficiency of the single event effect(SEE)experiments on the 100 MeV proton cyclotron of China Institute of Atomic Energy,a binary energy degrader that can lower the initial proton energy to other values rapidly is designed for the 100 MeV protons provided by the accelerator.The energy degrader is comprised of six aluminum plates of 0.5,1,2,4,8,16 and 32 mm at thickness,where the thickness of the latter plate is twice that of the previous one.We introduce the concept of relative thickness,which can also represent the order of the energy of the produced protons,and the state or operation of the degrader.The energy interval of 61 protons with energy above 9.69 MeV,produced by the degrader,is between 0.84 MeV and 4.09 MeV.And their energy straggling degree is less than 10%,and full width at half maximum of the scattering angle is less than 45 mrad.So the energy degrader basically meets the requirements of the proton SEE experiments.The influence of the initial proton energy accuracy of the protons directly provided by the accelerator on the residual energy after they have passed through the degrader is discussed.It is found that the lower the residual energy,the greater the influence is.In addition,the degrader is also suitable for protons in the 70-100 MeV energy range that the accelerator can directly provide,and more continuous energy can be obtained by using more plates designed with this method.The design method of the energy reducer proposed in this paper is simple and effective,and has a strong reference value.