Beam load estimates for the PS2 Beam Dump Systems

1. Beam load estimates for the PS2 Beam Dump Systems T. Kramer, M. Benedikt, B. Goddard

2. Main PS2 design parameters and key assumptions for the dump load calculations • Assumed 200 days of operation • Maximum of 1.08 x 1021 protons /y • All calculations are done in a rather conservative way T. Kramer AB-BT-TL

3. Dump functionalities • Injection line setting up • Fast injection setting up • H- Injection • Emergency abort • Machine development • Machine setting up • Extraction line setting up • Slow extraction ‘remaining beam’ T. Kramer AB-BT-TL

4. H- Injection • 6.4x1019 p.a. (5.92%) @ 4 GeV details later…. • Emergency beam abort • assumed 0.5% of cycles dumped • 5.4x1018 (0.5%) particles p.a. (50% @ 4-20 GeV) • Machine setting up • 6 days (2 per beam); 20% of full intensity • 6.5x1018 p.a. (0.6%) (50% @ 4-20GeV) • Machine development • 100h p.a. 20% of full intensity • 4.3x1018 p.a. (0.4%) (50% @ 4-20 GeV) • Particles remaining after slow extraction • Max. 1 % remaining particles; 50 GeV; operational 50% p.a.; 3.6s cycle • 3.6x1018 p.a. (0.33%) • Fast injection setting up and failures • 1 day p.a.; 20% dumped; 100 failures p.a. • 1.08x1018 p.a. (0.1%) @ 4 GeV • Setting up of injection transfer line • 4 days p.a.; 10% intensity; 20 foil exchange interventions; • 3.06x1018 p.a. (0.28%) @ 4 GeV • Setting up of extraction transfer line • 2 days p.a.; 30% intensity; • 3.25x1018 p.a. (0.3%) @ 50 GeV T. Kramer AB-BT-TL

5. Summary of beam loads Table 1: Beam loads @ “high Energy” Table 2: Beam loads @ “low Energy” T. Kramer AB-BT-TL

6. Schematic overview PS2 injection transfer line dump TED(s) PS2 extraction line dump TED SPS External H- injection dump ? ? TT12 TT10 from SPL EAs Internal fast injection dump External beam line dump PS2 Internal emergency dump T. Kramer AB-BT-TL

7. H- Injection - Beam Loads • Unstripped beam • 2 kW unstripped H-,H0 (5% efficiency) • 5.4x1019 p.a. (5%) • Yearly startup • 8x1018 p.a. (0.75%) • Setting up • Injection systems / foil exchange • 1.8x1018 p.a. (0.16%) T. Kramer AB-BT-TL

8. H- Injection - extract beam back to TT10 Overview of PS2 H-Injection; B. Goddard; PS2 meeting; 05/2007 T. Kramer AB-BT-TL

9. H- Injection - Factors of Influence Foil material • Stripping efficiency • Emittance dilution • Foil heating To be considered: • Lorentz Stripping • H0 excited states Foil thickness Temperature Stripping efficiency Beam blow up 5% Lifetime <0,1 pi mm mrad Losses! Beam load H0/H- Some optimization should be possible - studies Size, activation, position of the beam dump T. Kramer AB-BT-TL

10. Internal emergency dump • Advantages • System is easier to build, cheaper, desirable from point of operations, “some internal dump” to set up the extraction is anyway needed • Disadvantage • For operations like in the SPS a very high beam load is expected - Radiation source within the machine • Possible solution (as proposed): • Internal dump only takes the beam which really has to go there (8x1018 4-20 GeV + 2.7x1018 p@50 GeV p.a.) • Whenever there is time to extract the beam safely a beam line dump is used (slow extraction, machine development. 5.5x1018 @ 20-50 GeV + 6.9x1018 @ 50GeV p.a. ) • External dump at end of beamline in well-shielded EA zone? T. Kramer AB-BT-TL

11. Summary of loads and issues • Issues • Need for TEDs/beam stoppers at the end of transfer lines…including for ions and p+ from PSB before SPL comes on line. • Configuration for injection and extraction region….becoming congested. • Extraction and dumping of unstripped H- beam (acceptance, losses, …) • Optimization of losses for H- injection? Studies need to be done… • Conservative calculation to keep the highest degree of freedom; If we have serious problems concerning feasibility (costs) we have to define more accurate operations and design parameters and look into detail again. T. Kramer AB-BT-TL