As you can see from the attached mail the accesses needed by STAR have been quite necessary, and will diminish the available beam in the coming days.
Please all shifters - read Hiro's e-mail carefully. The procedure is also documented in
the si-dete description in the procedure book. Please read this carefully.
----- Original Message -----
From: Angelika Drees
Sent: Saturday, November 10, 2001 11:27 PM
Subject: bad news
Hey everybody,
due to some problem with my local PC (with all this beautiful mailing
list on it!) I couldn't get in contact with you earlier. I apologize.
Let me first start with friday before we get to the real bad news.
Realizing that the rates thursday-friday night didn't quite match our
expectation we used the end of a store for local and global decoupling
at storage. This was followed by unsuccessful octupole studies and a
short store (again with poor rates) after which we granted ring access
upon experiments request. While ramping down current busses feeding the
STAR magnet sparked and arched causing major damage evaporating the
aluminum welding edges and pieces of the cross bar at the location of
the contact. Parts of the cables nearby melted. In order to bring STAR
back into business as quickly as possible significant amount of IR
access is needed. This is the tentative schedule:
* Sunday, 4 h access from 10:00 am -2:00 pm: get the cross bar out of
wide angle hall for repair
* Tuesday, 18 h, 6:00 am-24:00 pm: get cross bar back in, rewire and
check, reassemble, magnet hot test, magnet heat run
RHIC should run for the other experiments for the rest of the weekend
including Veterans Day on monday. Plans for 3m beta* injection on
tuesday have to be postponed. Unfortunately today we had one 4 h store
only and a STAR access for diagnosing the magnet problem followed by a
power dip and tandem failure. At this point we are dealing with RF
problems and lost the last ramp at the top due to spontaneous debunching
in Blue. We just recovered from the QLI caused by dumping the debunched
beam.
Polarized protons were accelerated in the booster up to extraction
energy into the AGS. No progress was made so far injecting into the AGS
but RF people are currently in and ready to work on it as soon as we
have a RHIC store in. Lets cross fingers,
\|/
Angelika (.~.)
o0(_)0o
-----------------------------------------------------------
Angelika Drees (Collider-Accelerator Department, AP group)
BNL, Building 911b-210
work: (631) 344 2348
FAX: (631) 344 5954
home: (631) 474 3884
--
\|/
Angelika (.~.)
o0(_)0o
-----------------------------------------------------------
Angelika Drees (Collider-Accelerator Department, AP group)
BNL, Building 911b-210
work: (631) 344 2348
FAX: (631) 344 5954
home: (631) 474 3884
This archive was generated by hypermail 2b30 : Sun Nov 11 2001 - 09:14:08 EST