@article{oai:repo.qst.go.jp:00049564,
 author = {Yoshida, M. and Oohara, W. and 市川, 雅浩 and 平塚, 淳一 and 梅田, 尚孝 and 小島, 有志 and 柏木, 美恵子 and Ichikawa, Masahiro and Hiratsuka, Junichi and Umeda, Naotaka and Kojima, Atsushi and Kashiwagi, Mieko},
 journal = {AIP Conference Proseedings},
 month = {Dec},
 note = {In order to evaluate deposition of cesium (Cs) in the plasma grid (PG) and investigate the origin of the gradual degradation of the negative ion current in a 100 s long pulsed operation in the JT-60SA negative ion source, Cs behavior
in the source is model. To do this, Cs adsorption/desorption coefficient with a wide range of temperature is experimentally measured by a surface ionization detector and a quartz crystal microbalance. As a result, both of the adsorption and desorption are drastically varied at temperature range from room temperature to 100 oC. Based on these data, the model calculates the amounts of the Cs mass in the chamber wall and PG. The calculation result shows that, in the operation, an increase of temperature in the chamber wall (Twall) causes the evaporation of the huge amount of Cs in it. This leads to over pilling-up of Cs in the PG and the slight degradation of the negative ion production. Therefore, it is found that the constant temperature operation is needed to sustain the thickness of the Cs monolayer in the PG, and the Twall is desired to be less than 60 oC to suppress the evaporation of Cs in the chamber wall. According to this model, it is showed that there are many combinations of the temperatures to achieve it with low Cs consumption.},
 title = {Evaluation of the temperature dependence of the Cesium deposition on the plasma grid in the JT-60SA negative ion source},
 volume = {2052},
 year = {2018}
}