1. HER vacuum study June 2006 J. Kaminski weekly MDI meeting 7/13/2006

2. 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.

3. Definitions Beam loss: lumi ts >5000 & 0.9*lumi ts > lumi ts+1 & lumi of either ts+1, +2 or +3<1000) Vacuum activities vacuum ts >vacuum ts-4 +3nT for 2 consecutive ts vacuum ts >vacuum av +4nT for 2 consecutive ts For both quantities there are independent searches.

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

5. 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 9052 PR06 9132 PR12 6162

6. Results of vacuum activities during constant luminosity

7. 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 6082PR02 9132

8. Results of vacuum activities during increasing luminosity (filling)

9. 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 9132PR12 6082

10. Results of vacuum activities during decreasing luminosity (coast down)

11. JULY 1-11 There were 27 vacuum activities: lead to a beam loss lead to (small) lumi dips had no effect

12. 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