CMS Double Chooz HESS Edelweiss Herschel ALICE Detecting radiations from the Universe. EXPERIENCE WITH VACUUM SYSTEM FROM DESY AND CEA SOLUTIONS TTC topical workshop on clean room assembly | Stéphane BERRY SPECIFICATION OF VACUUM INFRASTRUCTURE, VACUUM EQUIPMENT AND VACUUM PROCEDURES

PUMPING AND VENTING UP TO ATM. Particles should neither move nor be introduced in cavities during venting to Atm. And pumping stages. Studies on pipe 10m, 63mm reproducing XFEL module ( Ref SRF2009-THPP0104) Movement of particles is mainly observed at the position next to the pumping and venting ports. The long tube homogenizes the gas flow and reduces turbulences. During pump down the number of particles decreases with decreasing pressure, indicating a reduction of turbulences. In the dirty system particles could be measured down to a pressure of about 100 mbar. If turbulences are again introduced by sudden changes of the throughput of e.g. changing the position of a needle valve, particles had been detected down to pressures of about 1 mbar. Only for pressures < 1 mbar no more particle movement has been observed even when moving valves. -Use a diffuser to reduce turbulences -Gauges to mesure precisely 1mbar around Atm -Venting/pumping: N2 flow (1-1000mbar –  p(cav-pump) <1mbar) : 50 mbar l/s -For venting particle filtered gas (N2 or Ar) (particle size ≤ 0.04 mm) -a gas quality of % has to be used: evaporated nitrogen | PAGE 2 as far as possible from components being sensitive to particles Manual valves, even needle valves, not well suited to adjust the gas flow After venting a system  p between the vacuum vessel and atmosphere should be Δp < 1 mbar before opening Example: AC150 uncontrolled venting from vacuum to 300 mbar 39 to 9 MV/m 3L/min of N2

8 DESY pumping units installed outside (Rec and CC / SA) : Fully remote control (Inc. Web) NOT automated (vacuum skills) Pump slowly, leak check, vent slowly but NOT flush The mass spectrometer can used either a residual gas analyser (RGA) or leak test unit VACUUM TOOLS (COLD COUPLER WS. + LAST LEAK TEST OF STRING) | PAGE 3 TTC topical workshop on clean room assembly | Nov Rails

DESY UNITS (FLUSHING ISSUE) Assemble parts with N2 flushing 10L/min, dry and filtered Cavity and Nitrogen manual valves: identical => pump damaged or process delay… manual => if forgotten cavity back to HPR… Do: different type of manual valves for nitrogen line on each pumping unit Aptech springless series AZ mbarl/s Check: leak tightness and particulates generation : OK Ceramic Filter Removal Rating > % at μm Analyse: CCC564 out of XM5 (N2 forgotten) !! Plan: Next step automated start of nitrogen flushing when opening the object to be assembled (cavity or coupler on its TWG) Goal: compensate for human factor | PAGE 4 N2 After Before

3 CEA pumping units (SA) : Distributed pumping system (turbo in ISO4 (T) and primary pump cellar (P)) remote control (Excep. Web), SEMI-automated (no skills) Pump, leak check, vent slowly and flush nitrogen through the assembled parts VACUUM TOOLS (STRING ASSEMBLY) | PAGE 5 TTC topical workshop on clean room assembly | Nov Rails

QUALIFICATION OF PUMPING/FLUSHING LINES For the particle counting qualification of vacuum lines see: EDMS Nr.: D* Rev: B “Series surface and acceptance test preparation of superconducting cavities for the European XFEL” (XFEL/A-D), 2009 What about DN40CF all metal valves ? | PAGE 6 TTC topical workshop on clean room assembly | Nov T part changed

DN40CF PARTICLE MEASUREMENT | PAGE 7 TTC topical workshop on clean room assembly | Nov

COLD COUPLER ASSEMBLY (LEAK CHECK ISSUE) Coupler pairs first leak check: Check: Leak on the coupler itself (TTF3) revealed during cavity string leak test (XM1) Admit : Helium spraying method hardly able to detect a leak in the mbarl/s range in a clean room (air flow spread helium) according to NF EN ind. A standard Helium spray to localise not to quantify. Quantify down to Pa.m3/s Plan: to build a simple plastic box for TWG with couplers Do: global leak test of pairs of coupler at the 1 st leak check (reception or ISO4-CC) Global test instead of spraying test (same process time more sensitive) | PAGE 8

TTC topical workshop on clean room assembly | Nov RESIDUAL GAS ANALYSIS Totale Pressure: Ptot 45 is less than 10-3 Ptot If the pressure of the device-under-test is below 10-8 mbar, it is required that all peaks including and above 45 are less than a per mille of the total pressure. If the pressure is between 10-7 and 10-8 mbar the DESY spec is applied as is, meaning the summation is required. Difficult to acheive: a time slot of validation is small | PAGE 9

| PAGE 10 TTC topical workshop on clean room assembly | Nov For series production : Is RGA needed if the component already got a conform RGA?

| PAGE 11 TTC topical workshop on clean room assembly | Nov

| PAGE 12 TTC topical workshop on clean room assembly | Nov WHY CLEAN ROOM ASSEMBLY ? Field Emission is often a limiting factor for cavities Polishing to get smoother surface High Pressure Rinsing with UltraPure Water Cavity assembly in clean room Clean Room Low dust environment, pressure, temperature et humidity monitored (ISO4-ISO5-ISO7) Remove metallic dust Outside of component Fastening (*new *clean) Gasket (*procurement) Components clean on outer surface Class 10