Wednesday 24th June 2015

Post date: Jun 24, 2015 5:09:24 AM

This morning we set up the machine with RF and started taking accelerated COD measurements. Screenshot of the oscilloscope with accelerated beam here:

https://drive.google.com/open?id=0B0TZJx0b9o5zRVhtUWJsc1JtNWc&authuser=0

We can only take these up to around 60 MeV (13msec) as the extension pieces of the radial probes prevent us pulling them out further without breaking vacuum to remove these pieces. Once we get to the tune measurement we will have to do this as it's important to see the tunes over the full energy range.

At about 6pm Suzie had a quick look at the results using David K's scripts. It's not great news really, it looks like the COD is almost double what it was before!? We use 700A excitation current but the pole is different so (to be fair) the field will be different.

Note: Plot of present results attached using 5 sigma threshold on time to loss analysis.

Interestingly the COD is growing fairly significantly with energy. Ishi-san says they have some evidence previously that it does this but then reduces a bit again further up the acceleration cycle... (why??)

We are now (this evening) turning up the corrector to 900A and beginning to take the next set of COD data. Let's see...