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