SRF2023 - List of Authors (Katayama, R.)

Paper	Title	Page
MOPMB033	Efforts to Suppress Field Emission in SRF Cavities at KEK	167
	M. Omet, H. Araki, T. Dohmae, H. Ito, R. Katayama, K. Umemori, Y. Yamamoto KEK, Ibaraki, Japan
	Our main objective is to achieve as high as possible quality factors Q₀ and maximal accelerating voltages E_acc within 1.3 GHz superconducting radio frequency (SRF) cavities. Beside an adequate surface treatment, key to achieve good performance is a proper assembly in the clean room prior cavity testing or operation. In this contribution we present the methods and results of our efforts to get a better understanding of our clean room environment and the particulate generation caused during the assembly work. Furthermore, we present the measures taken to suppress filed emission, followed by an analysis of vertical test results of the last six years.
	Poster MOPMB033 [1.532 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB033
About •	Received ※ 14 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 02 September 2023 — Issue date ※ 02 September 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB029	Measurement of Particulates under Slow Pumping after High Pressure Rinsing of Superconducting Cavity by Using Modified Slow Pumping System	458
	H. Sakai, E. Kako, R. Katayama, K. Umemori KEK, Ibaraki, Japan
	Funding: This research was partially supported by the research fund from Ministry of Education, Culture, Sports, Science and Technology (MEXT). Slow pumping system was used for particle free vacuum pumping in Superconducting rf accelerator. In KEK, recently slow pumping system was developed for the cryomodule assembly work for STF 9-cell cavities and worked well to reduce the particulates movements under pumping. However, this slow pumping system want to be used for preparation of vertical test. Before assembly work in clean room for vertical test, we normally apply high pressure rinsing. There were many waters in the cavity. Therefore, we kept one night to dry inside cavity in clean room. Unfortunately, there were some waters in the cavity even though we kept drying in clean room for one night. This water might make some icing under pumping and stop pumping in mass flow meter, which used for slow pumping to control the mass flow. Therefore, we modify the slow pumping system to be robust under slow pumping even when water exists in the cavity. In this paper, we present the modified slow pumping system in KEK and the results of the vacuum trend through slow pumping of 9-cell superconducting cavity. Under slow pumping, we measure the particulates after high pressure rinsing by using vacuum particle monitor.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB029
About •	Received ※ 16 June 2023 — Revised ※ 26 June 2023 — Accepted ※ 21 August 2023 — Issue date ※ 22 August 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Efforts to Suppress Field Emission in SRF Cavities at KEK

167

M. Omet, H. Araki, T. Dohmae, H. Ito, R. Katayama, K. Umemori, Y. Yamamoto
KEK, Ibaraki, Japan

Our main objective is to achieve as high as possible quality factors Q₀ and maximal accelerating voltages E_acc within 1.3 GHz superconducting radio frequency (SRF) cavities. Beside an adequate surface treatment, key to achieve good performance is a proper assembly in the clean room prior cavity testing or operation. In this contribution we present the methods and results of our efforts to get a better understanding of our clean room environment and the particulate generation caused during the assembly work. Furthermore, we present the measures taken to suppress filed emission, followed by an analysis of vertical test results of the last six years.

Poster MOPMB033 [1.532 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB033

About •

Received ※ 14 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 02 September 2023 — Issue date ※ 02 September 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB029

Measurement of Particulates under Slow Pumping after High Pressure Rinsing of Superconducting Cavity by Using Modified Slow Pumping System

458

H. Sakai, E. Kako, R. Katayama, K. Umemori
KEK, Ibaraki, Japan

Funding: This research was partially supported by the research fund from Ministry of Education, Culture, Sports, Science and Technology (MEXT).
Slow pumping system was used for particle free vacuum pumping in Superconducting rf accelerator. In KEK, recently slow pumping system was developed for the cryomodule assembly work for STF 9-cell cavities and worked well to reduce the particulates movements under pumping. However, this slow pumping system want to be used for preparation of vertical test. Before assembly work in clean room for vertical test, we normally apply high pressure rinsing. There were many waters in the cavity. Therefore, we kept one night to dry inside cavity in clean room. Unfortunately, there were some waters in the cavity even though we kept drying in clean room for one night. This water might make some icing under pumping and stop pumping in mass flow meter, which used for slow pumping to control the mass flow. Therefore, we modify the slow pumping system to be robust under slow pumping even when water exists in the cavity. In this paper, we present the modified slow pumping system in KEK and the results of the vacuum trend through slow pumping of 9-cell superconducting cavity. Under slow pumping, we measure the particulates after high pressure rinsing by using vacuum particle monitor.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB029

About •

Received ※ 16 June 2023 — Revised ※ 26 June 2023 — Accepted ※ 21 August 2023 — Issue date ※ 22 August 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)