1 / 4

Orbit Correctors Analysis and Remedies for MCB-induced Beam Loss

Detailed analysis of the 752 MCBH(V) SSS orbit corrector circuits powered individually, with PC installations in a radiation environment. Discussion on circuit time constants, crowbar resistors, and implications for electrical safety. Proposal for remedies to reduce beam loss and discuss the possibility of removing crowbar resistors. Rapid decision-making crucial as PCs are in production.

norton
Télécharger la présentation

Orbit Correctors Analysis and Remedies for MCB-induced Beam Loss

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. MCB orbit correctors • There are 752 MCBH(V) SSS orbit corrector circuits. • Individually powered by a ± 60 A, ± 8 V converter. • PCs installed in the tunnel (radiation). • PCs are in production today. • The design MTBF is 100’000 hours •  1 failure in operation every 100 hours. • Assuming ½ MCBs have significant kicks, we may get 1 MCB-induced beam loss per week due to our orbit tight tolerances ! AB-CO TC / J. Wenninger

  2. Crowbar In case of PC failure the magnet is shorted and discharged through a crowbar. • Time constants : • without crowbar 85-130 seconds • with crowbar 30-35 seconds - mostly due to 100 mresistors AB-CO TC / J. Wenninger

  3. Remedies • The orbit FB could save the beam : • The FB must switch in a compensating scheme based on nearby correctors (or equivalent)  reduce effect to a local bump. • The FB must be informed rapidly – time scale of 1 second or less. • The circuit time constants should be as long as possible. • With the 2 crowbar resistors the situation is very tight… • From MP point of view, the MCBs are slow enough even with crowbar resistors not to present a major problem. But the slow is beautiful for MP  slower is better ! AB-CO TC / J. Wenninger

  4. Can we remove 1 or both crowbar resistors ? • Meeting with all concerned parties (AB & AT) : • The crowbar resistors have no role in protecting the magnets. The magnets are self-protected. • Motivation behind resistors seems to be a shorter circuit discharge time. • PC tests performed without crowbar resistors by AB/PO indicate that the resistors can be removed. • Implications for electrical safety, since it takes then ~ 10 minutes for the current to go from 60 to below 1 A for the slowest elements. • need a rapid decision since the PCs are in production. • ECR will be prepared this week. AB-CO TC / J. Wenninger

More Related