1. vacuum conditions in PANDA pbar-line Alexander Gruber, SMI, Vienna, Austria

2. A. Gruber XXVIII. PANDA meeting GSI 02.03.20092 PANDA layout status as of week 08/2009 extending dump pipes with additional 150 mm Ø tube, so that dump outside cut-out of yoke some changes in design vacuum system since Dec. 2008: extending vertical pipes of cross, so that gate valves outside of muon chambers opening Ø of tube inside FS to 180 mm luminosity monitor (placeholder) Ø 250 mm

3. A. Gruber XXVIII. PANDA meeting GSI 02.03.20093 PANDA vacuum system status as of week 09/2009 some changes in design since Dec. 2008 (some of which will be discussed this week): opening angle 45° - to be discussed flange at z=-852 mm (outside of endcap EMC) – to be discussed luminosity monitor (placeholder) Ø 250 mm

4. A. Gruber XXVIII. PANDA meeting GSI 02.03.20094 calculations vacuum in pbar-line studies on effect of opening angle of big upstream conus on vacuum in the upstream section:  pressure along 150 mm Ø pipe towards upstream TMPs only decreasing from 10 -6 to upper 10 -7 mbar alarm: many pbars destroyed before reaching IP (thickness of residual gas) again review of vacuum situation in pbar-line with current layout try putting cryopump inside beam pipe next to cone calculations with VAKLOOP:  pressure profile for H 2  calculating thickness of residual H 2 -gas outgassing of air (N 2 ):  pressure profile of air due to outgassing from walls only  thickness of residual gas (N 2 )

5. A. Gruber XXVIII. PANDA meeting GSI 02.03.20095 geometry for calculations for H 2 leak rate from target: 10 -4 mbar*l/s 10 -3 mbar*l/s 10 -2 mbar*l/s leak rate from dump: 10 -4 mbar*l/s S H2 ~ 750 l/s S H2 ~ 480 l/s TMP S H2 ~ 750 l/s IGP S H2 ~ 800 l/s cryopump: 100 mm long 100 mm Ø (one cold facet) 50 mm Ø (2 cold facets) S = 10 l/s*cm²  S = 3142 l/s

6. A. Gruber XXVIII. PANDA meeting GSI 02.03.20096 Schematics of PANDA for VAKLOOP 6 5 2 3 4 1 10 11 12 13 14 15 16 1 … gate valve from HESR 3,4 … upstream TMPs 5 … end cone 4,5 … TMPs of collimator chamber 6 … IP 7 … “leak” from target 8 … “leak” from dump 9 … end of target cross (20 mm Ø ) 11,12 … TMPs behind TS 14 … TMP behind FS 15 … ion getter pump 16 … gate valve to HESR 7 8 9

7. A. Gruber XXVIII. PANDA meeting GSI 02.03.20097 pressure along pbar-line

8. A. Gruber XXVIII. PANDA meeting GSI 02.03.20098 sections 0 & 1

9. A. Gruber XXVIII. PANDA meeting GSI 02.03.20099 pressure in sections 0 & 1

10. A. Gruber XXVIII. PANDA meeting GSI 02.03.200910 sections 2 & 3

11. A. Gruber XXVIII. PANDA meeting GSI 02.03.200911 pressure in section 2

12. A. Gruber XXVIII. PANDA meeting GSI 02.03.200912 pressure in section 3

13. A. Gruber XXVIII. PANDA meeting GSI 02.03.200913 section 4

14. A. Gruber XXVIII. PANDA meeting GSI 02.03.200914 pressure in section 4

15. A. Gruber XXVIII. PANDA meeting GSI 02.03.200915 pressure along pbar-line

16. A. Gruber XXVIII. PANDA meeting GSI 02.03.200916 sections 5 & 6

17. A. Gruber XXVIII. PANDA meeting GSI 02.03.200917 pressure in sections 5 & 6

18. A. Gruber XXVIII. PANDA meeting GSI 02.03.200918 pressure along pbar-line

19. A. Gruber XXVIII. PANDA meeting GSI 02.03.200919 geometry for calculations for N 2 no leak rate from target no leak rate from dump S N2 ~ 1000 l/s S N2 ~ 500 l/s TMP S N2 ~ 1000 l/s IGP S N2 ~ 800 l/s cryopump: 100 mm long 100 mm Ø (one cold facet) 50 mm Ø (2 cold facets) S = 10 l/(s*cm²)  S = 3142 l/s all surfaces outgassing with 1*10 -10 mbar*l/(s*cm²) (stainless steel) 5*10 -10 mbar*l/(s*cm²) (Ti) (values after pumping > 24 h) [J.F.O‘Hanlon: User guide to vacuum technology]

20. A. Gruber XXVIII. PANDA meeting GSI 02.03.200920 total pressure in pbar-line

21. A. Gruber XXVIII. PANDA meeting GSI 02.03.200921 total pressure in pbar-line

22. A. Gruber XXVIII. PANDA meeting GSI 02.03.200922 resulting thickness residual gas

23. A. Gruber XXVIII. PANDA meeting GSI 02.03.200923 conclusions Need concrete numbers of gas load into pbar-line from both targets (and dump) Since 10 -2 mbar*l/s is realistic influx  resulting thickness residual gas almost in order of target thickness ! Could reduce thickness of residual gas in backstream section with a cryopump (enough space available) BUT: what about thickness in downstream part inside the TS ?