HER vacuum study June 2006

J. Kaminskiweekly MDI meeting

7/13/2006

Aim of study

The HER vacuum level as seen by the distributed ion pumps (VDIPs) was studied in combination with the luminosity.

This was done to see, if there are any vacuum leaks/break downs that lead to beam losses.

Definitions

Beam loss:

lumits>5000 & 0.9*lumits> lumits+1 & lumi of either ts+1, +2 or +3<1000)

Vacuum activities

vacuumts>vacuumts-4 +3nT for 2 consecutive ts

vacuumts>vacuumav +4nT for 2 consecutive ts

For both quantities there are independent searches.

Results

There were 75 vacuum activities: 13 lead to a beam loss 16 lead to (small) lumi dips 46 had no effect

Results of vacuum activities during constant luminosity

22 vacuum activities during stable luminosity 8 lead to a beam loss 8 lead to a (small) lumi dip 6 had no effect

PR10 9052PR06 9132 PR12 6162

Results of vacuum activities during constant luminosity

Results of vacuum activities during increasing luminosity (filling)

47 vacuum activities during increasing luminosity 4 lead to a beam loss 4 lead to a (small) lumi dip 39 had no effect

PR06 9132PR02 6082 PR02 9132

Results of vacuum activities during increasing luminosity (filling)

Results of vacuum activities during decreasing luminosity (coast down)

6 vacuum activities during decreasing luminosity 1 lead to a beam loss 4 lead to a (small) lumi dip 1 had no effect

PR02 6042 PR12 9132 PR12 6082

Results of vacuum activities during decreasing luminosity (coast down)

JULY 1-11

There were 27 vacuum activities: lead to a beam loss lead to (small) lumi dips had no effect

JULY 1-11

1 vacuum activities during decreasing luminosity 1 had no effect

21 vacuum activities during increasing luminosity 4 lead to a beam loss 5 lead to a (small) lumi dip 12 had no effect

There were 5 vacuum activities during stable luminosity: 1 lead to a beam loss 1 lead to (small) lumi dips 3 had no effect