1 / 6

PEP-II 2002-2003 Vacuum Failures

PEP-II 2002-2003 Vacuum Failures. PEP-II Machine Advisory Committee. Elliptical Vacuum Valve Failure. On 23 Jan 03, LER elliptical vacuum valves, PR02 VACV 1153 & PR02 VACV 3044 would not fully open following 2 Hour ROD. Both valves had damage to their RF seals and actuating mechanisms.

daryl
Download Presentation

PEP-II 2002-2003 Vacuum Failures

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. PEP-II 2002-2003 Vacuum Failures PEP-IIMachine Advisory Committee S. DeBarger

  2. Elliptical Vacuum Valve Failure • On 23 Jan 03, LER elliptical vacuum valves, PR02 VACV 1153 & PR02 VACV 3044 would not fully open following 2 Hour ROD. • Both valves had damage to their RF seals and actuating mechanisms. • The valves were removed and replaced with spool pieces. • Failure is attributed to deficiencies in the design of the RF shields, compounded by a workmanship defect in one valve. • Beam Time Lost 26.00 hours Current Status • Valves repaired by VAT using existing RF seal design. Spare valve installed at VACV 3044 location. • Gap rings at this location have been replaced with gap rings of the correct size. • Existing elliptical and round valves show heating by the beam. This is not adequately measured. S. DeBarger

  3. LER Frangible Link • On 19 Apr 03, pressure at the IP became elevated. Beam was unrunnable due to high LER Backgrounds. • Leak discovered on upstream LER Frangible Link. • Several attempts to VacSeal were short-lived; finally the leaking bellows module was replaced. • During replacement of the leaking bellows, a second bellows module was found to have damaged RF fingers. • Both bellows were replaced with spares and reinstalled. • Failure is attributed to mishandling of the bellows during or after installation, causing the RF fingers to lose contact with the beampipe. It is possible that corrosion also played a part in the failure. • Beam Time Lost 47.50 hours Current Status • New spare modules being fabricated using existing design • New bellows restraints for transportation & for normal operation to be designed and fabricated S. DeBarger

  4. Mystery Pressure Bump Near IP • On 26 Apr 03, pressure at the IP became elevated. • During leakchecking, pressure improved. No leak was located. • Lots of speculation … could this be the first appearance of a problem that would resurface? • Beam Time Lost 15.50 hours S. DeBarger

  5. LER Arc 1 Pumping Chamber • On 9 May 03, pressure near PR02 VP1151 rose. • Leakchecking revealed a leak in a weld prep on the pumping chamber aluminum extrusion. • Attempts to seal the leak with VacSeal or to establish a guard vacuum were unsuccessful. • Replaced the leaking chamber on 17 May 03. • Beam Time Lost 48.50 hours Current Status • Chamber to be repaired S. DeBarger

  6. Q2 Chamber • On 27 Jun 03, pressure began to rise at the IP. • Initial attempts to leakcheck did not locate a leak. • By 4 Jul 03 , the pressure had risen to the 10-4 level. Additional leakchecking revealed a water-to-vacuum leak in the Forward Q2 chamber. • Radial Ion Pump PR02 VP3012 failed on the 29th, possibly related to leakchecking activities. • Failure traced to a crack in the water-cooled mask due to a material defect • Beam Time Lost 50.1 hours Current Status • Chamber replaced with older version of the same chamber • After removal, discovered that the NEG pump had been overheated at some time, damaging the NEG material • Chamber repair appears not to be an option • Evaluating the performance of the installed chamber and comparing to future running scenarios S. DeBarger

More Related