SRF2011 - List of Authors (Saito, K.)

Paper

Title

Page

Development of the Demountable Damped Cavity

172

T. Konomi
Sokendai, Ibaraki, Japan
F. Furuta, K. Saito
KEK, Ibaraki, Japan
F. Yasuda
The University of Tokyo, Institute of Physics, Tokyo, Japan

We have designed a new HOM free cavity named Demountable Damped Cavity (DDC) as an ILC R&D. DDC has two design concepts. The first one is an axial symmetry to eliminate kick off effect by HOM coupler itself. DDC is applied coaxial structure along the beam axis to make strong coupling with HOM. HOM is damped on RF absorber at the end of coaxial waveguide and the accelerating mode is reflected by the choke filter mounted on the entrance of coaxial waveguide. The second concept is demountable structure which can make cleaning of end group easy in order to suppress the Q-slope problem at high field. MO sealing will be applied for the demountable joint. We have simulated the HOM damper structure, thermal structure, and the multipacting phenomena on single DDC. We have also simulated how DDC works on ICHIRO 9-cell cavity. Now we are fabricating single DDC. Cold test is also planned. In this paper, we will present the results of them.

TUPO014

High Gradient Results of ICHIRO 9-Cell Cavity in Collaboration With KEK and Jlab

386

F. Furuta, T. Konomi, K. Saito
KEK, Ibaraki, Japan
G.V. Eremeev, R.L. Geng
JLAB, Newport News, Virginia, USA

KEK and Jlab have continued S0-study collaboration on ICHIRO 9-cell cavities since 2008. In 2010, we have started S0 study on ICHIRO#7, full 9-cell cavity with end groups. Surface treatments and vertical tests have been repeated at Jlab. Maximum gradient of 40MV/m was achieved so far. We will describe the details of that and further plan of S0-study on ICHIRO 9-cell.

Poster TUPO014 [1.682 MB]

WEIOA02

Centrifugal Barrel Polishing (CBP) of SRF Cavities Worldwide

571

C.A. Cooper
Fermilab, Batavia, USA
B. Bullock
CLASSE, Ithaca, New York, USA
S.C. Joshi
RRCAT, Indore (M.P.), India
A.D. Palczewski
JLAB, Newport News, Virginia, USA
K. Saito
KEK, Ibaraki, Japan

Much interest was generated in the mid to late 1990s in an alternative cavity surface processing technique called CBP, that mechanically polishes the inside of SRF cavities by rotating them at high speeds while filled with abrasive media. This work, which was originally done at KEK by Kenji Saito & Tamawo Higuchi, has received renewed interest recently because of work done at Fermilab which has produced mirror like finishes on the 1.3 GHz Tesla-type cavity SRF surface. In addition to Fermilab & KEK, Cornell, Jefferson Lab and RRCAT are all exploring CBP as a cavity processing technique. CBP is interesting as a cavity processing technique because it removes defects associated with the manufacturing process, it can yield surface finishes (Ra) on the order of 10s of nanometers, it is a simple technology that could transfer easily to industry, it could help increase cavity yields and it requires less acid than other techniques. Recent progress and the current status of CBP as a baseline and repair technique will be discussed.

THPO013

Investigation of 9-Cell Cavity Performance Problem by Facilities in KEK AR East 2nd Experimental Hall

733

K. Saito, F. Furuta
KEK, Ibaraki, Japan
T. Konomi
Sokendai, Ibaraki, Japan
F. Yasuda
The University of Tokyo, Institute of Physics, Tokyo, Japan

So far our 9-cell cavity performance is often suffered from field emission. We are investigating our facilities at the KEK AR East 2nd experimental hall. We examined two points of view post EP/BCP cleaning and particle contamination. Particle contamination problem has been found in our HPR system, cavity assembly, and vacuum evacuation procedure. We have taken cures against these problems. We will report about these problems and the cured results on cavity performance in this paper.

Poster THPO013 [3.259 MB]

Paper	Title	Page
MOPO038	Development of the Demountable Damped Cavity	172
	T. Konomi Sokendai, Ibaraki, Japan F. Furuta, K. Saito KEK, Ibaraki, Japan F. Yasuda The University of Tokyo, Institute of Physics, Tokyo, Japan
	We have designed a new HOM free cavity named Demountable Damped Cavity (DDC) as an ILC R&D. DDC has two design concepts. The first one is an axial symmetry to eliminate kick off effect by HOM coupler itself. DDC is applied coaxial structure along the beam axis to make strong coupling with HOM. HOM is damped on RF absorber at the end of coaxial waveguide and the accelerating mode is reflected by the choke filter mounted on the entrance of coaxial waveguide. The second concept is demountable structure which can make cleaning of end group easy in order to suppress the Q-slope problem at high field. MO sealing will be applied for the demountable joint. We have simulated the HOM damper structure, thermal structure, and the multipacting phenomena on single DDC. We have also simulated how DDC works on ICHIRO 9-cell cavity. Now we are fabricating single DDC. Cold test is also planned. In this paper, we will present the results of them.

TUPO014	High Gradient Results of ICHIRO 9-Cell Cavity in Collaboration With KEK and Jlab	386
	F. Furuta, T. Konomi, K. Saito KEK, Ibaraki, Japan G.V. Eremeev, R.L. Geng JLAB, Newport News, Virginia, USA
	KEK and Jlab have continued S0-study collaboration on ICHIRO 9-cell cavities since 2008. In 2010, we have started S0 study on ICHIRO#7, full 9-cell cavity with end groups. Surface treatments and vertical tests have been repeated at Jlab. Maximum gradient of 40MV/m was achieved so far. We will describe the details of that and further plan of S0-study on ICHIRO 9-cell.
	Poster TUPO014 [1.682 MB]

WEIOA02	Centrifugal Barrel Polishing (CBP) of SRF Cavities Worldwide	571
	C.A. Cooper Fermilab, Batavia, USA B. Bullock CLASSE, Ithaca, New York, USA S.C. Joshi RRCAT, Indore (M.P.), India A.D. Palczewski JLAB, Newport News, Virginia, USA K. Saito KEK, Ibaraki, Japan
	Much interest was generated in the mid to late 1990s in an alternative cavity surface processing technique called CBP, that mechanically polishes the inside of SRF cavities by rotating them at high speeds while filled with abrasive media. This work, which was originally done at KEK by Kenji Saito & Tamawo Higuchi, has received renewed interest recently because of work done at Fermilab which has produced mirror like finishes on the 1.3 GHz Tesla-type cavity SRF surface. In addition to Fermilab & KEK, Cornell, Jefferson Lab and RRCAT are all exploring CBP as a cavity processing technique. CBP is interesting as a cavity processing technique because it removes defects associated with the manufacturing process, it can yield surface finishes (Ra) on the order of 10s of nanometers, it is a simple technology that could transfer easily to industry, it could help increase cavity yields and it requires less acid than other techniques. Recent progress and the current status of CBP as a baseline and repair technique will be discussed.

THPO013	Investigation of 9-Cell Cavity Performance Problem by Facilities in KEK AR East 2nd Experimental Hall	733
	K. Saito, F. Furuta KEK, Ibaraki, Japan T. Konomi Sokendai, Ibaraki, Japan F. Yasuda The University of Tokyo, Institute of Physics, Tokyo, Japan
	So far our 9-cell cavity performance is often suffered from field emission. We are investigating our facilities at the KEK AR East 2nd experimental hall. We examined two points of view post EP/BCP cleaning and particle contamination. Particle contamination problem has been found in our HPR system, cavity assembly, and vacuum evacuation procedure. We have taken cures against these problems. We will report about these problems and the cured results on cavity performance in this paper.
	Poster THPO013 [3.259 MB]