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.
Spectroscopic Study of Surface Treatments for Nb SRF Cavity
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