DEVELOPMENT OF A CONTROLLING METHOD FOR THE CARBON BUILD-UP ON THIN CARBON STRIPPER FOILS DURING BEAMBOM BARDMENT

1999年的第一个是设计和组装一个大的实验真空室（550毫米，H和500毫米，D），用于测量碳积累和碳剥离箔的寿命。该室由不锈钢组成，有两个红外线（1kW和2kW）和一个用于安装碳箔设备的转移杆。两台红外设备分别安装在碳箔中心位置两侧各45°方向。二是采用可控直流电弧放电法制备了极薄簇状碳膜（3.0±0.5μg/cm^2）。三是在东京工业大学4.75MeV Van de Graff加速器的辐照装置上，用1.5 ~ 2.0μA的3.2 MeV Ne^+离子束轰击下，测量团簇碳箔的碳积累和寿命。碳箔的寿命被定义为一个集成的光束电流（mC/cm^2）。用QMG-060质谱仪测定了真空腔内的总颗粒压力和残余气体。采用1.5 ~ 3.0μg/ CM ^2的亚利桑那CM箔作为标准监测厚度，确定箔的厚度并作为寿命的参考。用Si固态探测器测量了加热和不加热条件下积碳层和碳箔厚度的变化。我们进行了系统的实验测量，如1)积累与温度，2)寿命与温度，3)积累与寿命。从这些实验中，我们发现碳积聚的临界抑制温度为250±20℃，我们还发现碳积聚的完全可控温度约为450±20℃。通过成功地控制碳积聚，薄簇箔的寿命平均延长到1.7倍（300mC/cm^2），最大延长到2.5倍（450mC/cm^2）。这种寿命相当于比CM最佳碳箔（30mC/ CM ^2）长~ 15。少

The first in 1999 was to design and assemble a big experimental Vacuum Chamber (550mm, H and 500mm, D) for use in the measurements of Carbon build-up and the lifetime of Carbon Stripper foils. The chamber is composed of stainless steel and it has two infrared-rays (1kW and 2kW) and a transfer rod for mounting of carbon foils equipments. The two infrared-rays equipments were mounted at each 45°direction both side of the carbon foil at the central position.The second was to develop and prepare very thin cluster carbon foils (3.0±0.5μg/cm^2) by means of a controlled dc arc-discharge method.The Third was to measure the carbon build-up and the lifetime of the cluster carbon foils under the bombardment with a 3.2 MeV Ne^+ ion beam of 1.5 to 2.0μA from the irradiation facility of the 4.75MeV Van de Graff accelerator at the Tokyo Institute of Technology.The lifetime of the carbon foils was defined as an integrated beam current (mC/cm^2).The total particle pressure and the residual gases in the … More vacuum chamber were measured with a QMG-060 mass spectrometer. The Arizona CM foils of 1.5 to 3.0μg/cm^2 were used as a standard monitored thickness to determine the thickness of the foils and also as a reference of lifetime. The change in thickness of the carbon build-up and the carbon foil in the heating and the without heating was measured by Si solid-state detector.We carried out the systematic measurements of experiments such as 1) the build-up vs temperature, 2) lifetime vs temperature and 3) the build-up vs lifetime. From these experiments, we found that a critical suppressing temperature of the carbon build-up was 250±20℃ and we found also that the completely controllable temperature of the carbon build-up was approximately 450±20℃.By this successfully controlling of the carbon build-up, the lifetime of the thin cluster foil were extended to 1.7 times (300mC/cm^2) in average and 2.5 times (450mC/cm^2) longer in maximum than those without the controlling. This lifetime corresponds to 〜15 longer than compared to CM best carbon foils (30mC/cm^2). Less