Spectroscopic study of surface treatments for Nb SRF cavity ニオブ超伝導空洞の表面処理に関する電子分光学的研究
Spectroscopic study of surface treatments for Nb SRF cavity
Puneet Veer Tyagi
プニート ヴィール ティヤギ
Time goes by so fast. The last three years were highly eventful and every day presented new challenges and opportunities. This period has brought me valuable new experiences in both a scientific and personal perspective. Realizing the unique opportunity to obtain a Ph.D. degree would not have been possible without the contributions of many people. Foremost, I would like to thank Dr. Shigeki Kato for my integration in his group and allowing me to work in a nice scientific environment as well as discussing many topics of vacuum science and surface science with me. He fearlessly accepted me as a PhD candidate and was the main creator of the great ideas, techniques and whole background of this thesis. We experienced together all the ups and downs of routine work, the shared happiness of success and the depression of failure. He managed to teach me how to work independently (which is very important), but at any time, his useful advice was available to me. These three years, I spent as a part of surface analysis laboratory proved to be very helpful for me in developing new scientific ideas and skills. I would like to thank you for your help and sharp views, which really improved the quality of the thesis. On the personal side, he did not hesitate to invite his students to become an extended part of his family, I appreciate this immensely. I am very grateful to Dr. M. Nishiwaki who sets many things for me to start on my project. I gained a I am highly indebted to Dr. H. Hayano and Dr. T. Saeki for allowing me to work in STF and providing me their kind help and advices during the experiments. I express my gratitude to Dr. M. Sawabe and all the technical staff of STF for their kind help in performing electropolishing and buffered chemical polishing experiments. Two people with whom I enjoyed every moment in Tsukuba are Dr. Noguchi and Mr. Chouhan. They helped me in all spheres of life: during experiments as well as in daily life. I am fortunate to have colleagues like them. I also admire Mrs. Sonam Chouhan (wife of Mr. Vijay Chouhan), who cooked delicious food for me and invited many times for a nice food. I would like to acknowledge the Japanese government (MEXT : Ministry of Education, Culture, Sports, Science and Technology) for financial support in the form of Monbukagakusho scholarship. I am very thankful to Mr. Y. Aizawa, S. Hasegawa and other Sokendai staff for their valuable help in all administrative processes. I am highly obliged to Ulvac-PHI for providing me the TOF-SIMS analysis of our cavity EP 1 sample and Applied Surface Technologies, USA for providing the dry ice cleaning equipment. Also outside of science, there were people whose help and support was very important. I greatly admire my parents: Mr. Ajai Veer Singh Tyagi and Mrs. Sushila Tyagi. They have always encouraged me and supported me all the time from the joining of research program till today in every aspect. I also wish to express my feelings for my brother Dr. Vineet Veer Tyagi and sister in law Dr. Richa K. Tyagi for their full-fledged co-operation and inspiration. They are the ones who have always boosted my moral in carrying out my work. I also admire my niece Ananya, my little angel, who did not directly contributed to my thesis but gave me a lot of humor when talking to her. I forgot all the work stress when listening her childish talks and freshen myself. Finally, I would like to mention the great love and care of my wife Dr. Payal Tyagi during the last year of my thesis. I can't simply express her contribution in words. She has helped me in every aspects like thesis modification, moral support etc. Without her love and care, it would have been difficult for me to achieve my goals. Above all, I thank almighty God for providing me strength, motivation and courage.