1850 Gauss by pulse in JLAB

[Kenji Saito <kenji.saito@xxxxxx>]

Dear WG5 Asia menbers,

JLABのDr. Peter Kneiselからニオブ単結晶空洞(2.2GHz)の極最近の高電界試験結果 
が送られて来ました。
添付ファイルにあるようにパルス測定では、1850 Gaussを得ました。どうやらこの辺 
がcritcal fieldらしいとのことです。この値は、我々の1750+-100 Gaussの予想に合 
います。
1850 GaussはILC ICHIRO空洞では、まさに51MV/mに対応します。
2.2GHzを選んだ理由は、単結晶の大きさからきています。

斎藤

Hi Kenji,

I want to share with you some progress on the "Large Grain" cavity research.
We have build a 2.2 GHz cavity from a real single grain ( the center of the 
ingot
had such a large grain) and tested it last week and this week after baking.
Attached are the results: after the baking ( the cavity was only bcp'd and 
hydrogen degassed)
we reached Eacc = 38 MV/m in cw and ~43 MV/m pulsed ( 185 mT). There seemed 
to be a global
heating as you can see on the attached oscilloscope trace. In an ILC-LL 
cavity this
would correspond to Eacc ~ 51 MV/m and if we scale the surface resistance with
frequency, a Q of ~ 1.5 x 10e10. Of course, this has to be demonstrated on 
the "real thing".
So we are bulding now a scaled ILC_LL cavity at 2.3 GHz to take advantage 
of the
single crystal.

Greetings

Peter

How is the US_Japan collaboration coming along?
Also, you mentioned that the single cell cavity ( Gigi's) has been 
electropolished?

Attachment: RF test#1 results.pdf
Description: Adobe PDF document