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

第一次是在1999年，设计和组装了一个大型实验真空室(550 mm，H和500 mm，D)，用于测量碳积聚和碳剥离箔的寿命。该试验室由不锈钢组成，有两条红外线(1kW和2kW)和一根用于安装碳箔设备的传送杆。两台红外线装置安装在碳箔两侧各45°方向的中心位置。第二步是用受控直流弧放电法研制和制备超薄的团簇碳膜(3.0±0.5μg/cm2)。第三步是在东京工业大学4.75 MeV范德格拉夫加速器的辐照装置上用1.5~2.0μA的3.2 MeV Ne离子束轰击，测量了团簇碳膜的聚碳量和寿命。定义了碳膜的寿命作为积分束流(MC/cm^2)。总粒子压强和…中的残余气体用QMG-060型质谱仪测量更多的真空室。使用1.5到3.0μg/cm^2的亚利桑那州CM箔作为标准监测厚度，以确定箔的厚度，并作为寿命的参考。用硅固体探测器测量了加热和不加热时的积碳和碳箔厚度的变化，进行了1)积碳-温度，2)寿命-温度和3)积碳-寿命的系统测量。实验发现，碳积累的临界抑制温度为2 5 0±2 0℃，完全可控的碳积累温度约为4 5 0±2 0℃。通过对碳积累的成功控制，薄团簇箔的寿命平均延长了1.7倍(300mC/cm2)，最大延长了2.5倍(45 0mC/cm2)。这一寿命相当于比CM最佳碳箔(30mC/cm^2)长约15。较少

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