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ELENA Source Vacuum System, LNS
R. Kersevan
Integration and Installation Committe – 18 Sept 2014
ELENA LNS Vacuum System - R. Kersevan – IIC Meeting – 18Sept2014
Agenda:1. Integration Layout (LNS + first part of LNE00)2. Vacuum Hardware: Pumps, Gauges, Valves,
etc…3. Pressure Profile Calculations4. Conclusions
ELENA LNS Vacuum System - R. Kersevan – IIC Meeting – 18Sept2014
1. Design and Integration Status Report
• Design of the LNS line has evolved to a mature stage;
• All necessary vacuum devices have been integrated;
• Optimized design of a Differential Pumping System (DPS) has been done, and integrated;
ELENA LNS Vacuum System - R. Kersevan – IIC Meeting – 18Sept2014
1. Design and Integration Status Report
List of vacuum hardware:
• Pumps:
• 4x 1200 l/s turbos
• 1x 1400 l/s “ZAO” NEG
• 1x 1000 l/s NEXTorr
• Bellows: 3x
• Gauges: 4x ionization + 4x Pirani
• Gate Valves: 1x DN100 + 1x DN63 (Series 48, all-metal)
• Manual Valves: 3x DN35 (all-metal)
ELENA LNS Vacuum System - R. Kersevan – IIC Meeting – 18Sept2014
1. Pressure profile calculations• LNS, the Ion-Switch (IS), and the part of LNE00 connecting the IS with
LNR have been modelled in detail
• As usual, the montecarlo code Molflow+ has been used. The CAD models exported in STL format have been used
• The gas load of the H+- source, as per R. Gebel, has been simulated: 9.44101E-2 mbar*l/s (6 sccm)
• The transmission probability from the source to the “Y” chamber pumping the electrostatic (ES) kicker on LNR has been calculated
ELENA LNS Vacuum System - R. Kersevan – IIC Meeting – 18Sept2014
1. Transmission Probabilities (pumping surfaces in RED)• Source to IS: ~ 2.4E-4; IS to LNR: ~ 1.2E-2; Combined: ~3.0E-
6
• Gas Load to LNR: ~ 2.8E-7 mbar*l/s
ELENA LNS Vacuum System - R. Kersevan – IIC Meeting – 18Sept2014
5. Conclusions
• The challenging design of the DPS for LNS has been done: integration considerations have left only 60 cm for the DPS! In spite of that, only ~ 1 H2 molecule out of 4,500 reaches the Ion-Switch;
• Of the initial gas load of 9.44E-2 mbar*l/s only 2.8E-7 reach the “Y” chamber on LNR. A similar amount will reach LNR moving down LNI, to the injection septum/kicker assembly;
• The pressure rise at LNR will be only marginal, and should not saturate neither the NEG pumps nor the NEG-coating of the LNR;
• Fabrication of the components of LNS can and should start soon, in order to meet the pre-commissioning schedule;
• OPEN ISSUE: a 30 mm ID orifice restriction between the two domes of the DPS is suggested, as it decreases the transmission probability
ELENA LNS Vacuum System - R. Kersevan – IIC Meeting – 18Sept2014
Many thanks to C. Eymin, L. Dassa, S. Maridor for providing informations, documents, data and help