1. PSB H- injection concept J.Borburgh, C.Bracco, C.Carli, B.Goddard, M.Hourican, B.Mikulec, W.Weterings,

2. Contents H- injection general Concept for PSB – Distribution of beam to 4 PSB rings – Injection region geometry – Injection elements Specific features 09/11/20112Review on PSB 160 MeV H - Injection

3. H- is a negative ion of hydrogen – Two electrons attached to proton: binding energies -0.75 and -13.6 eV – Electrons are relatively easy to remove with a thin foil of some  m thickness (efficiency depends on energy and foil thickness). – Typically 1% of H 0, 10 -6 of H - Changing charge state important – Allows to accumulate p+ in same phase space area Why H-? 09/11/20113Review on PSB 160 MeV H - Injection

4. H- injection Crucial features are merging dipole (part of injection “chicane”) and stripping foil 09/11/20114Review on PSB 160 MeV H - Injection

5. H- injection Shifting the machine orbit with respect to foil (painting) fills machine aperture with beam 09/11/20115Review on PSB 160 MeV H - Injection

6. H- injection Chicane switches off to zero amplitude after injection Different intensities/emittances: number of injected turns – From 1 to 100 09/11/20116Review on PSB 160 MeV H - Injection

7. Main injection elements Beam distribution to 4 PSB rings Chicane dipoles BSW and power supplies Stripping foils and handling units Waste beam (H - /H 0 ) dump Horizontal painting kickers KSW and power supplies Dedicated beam instrumentation – BLMs, BTV screens, dump current monitoring, foil current monitoring Foil viewing system Vacuum chambers (especially BSW) Injection steering correctors 09/11/20117Review on PSB 160 MeV H - Injection

8. PSB injection layout 09/11/20118Review on PSB 160 MeV H - Injection

9. 3D layout of injection region 09/11/20119Review on PSB 160 MeV H - Injection 2.6 m

10. Bump heights Painting bump removes beam from foil quickly (~10 turns) – 27 mm clearance Chicane fall time slower (5 ms = 5000 turns) Vertical offset may also be present for vertical painting 09/11/201110Review on PSB 160 MeV H - Injection Chicane 46 mm Painting 35 mm 27 mm

11. 4 = 360 mm BI.DISBI.SMVBI.BVT 3 = 0 mm 2 = -360 mm 1 = -720 mm BI.DVT30 BI.QNO30 BI.QNO40 BI.DVT40 PSB Beam distribution to 4 PSB rings

12. Injection chicane Highly constrained by limited available space (2.6 m) “symmetric” layout with 66 mrad angles – 380/316 mm physical/magnetic dipole lengths – 0.34 T dipole field – BSW1 septum – BSW4 internal dump – Rbend dipoles – Ceramic chambers 09/11/201112Review on PSB 160 MeV H - Injection

13. Optics perturbation from chicane Additional focusing from strong dipoles produces b-beating – 50% beating in vertical plane with Rbends – Cannot be statically compensated as chicane strength changes – Make dipoles as long and as weak as possible (but space limited) Active compensation with trim quadrupoles at about ±3  /2 09/11/201113Review on PSB 160 MeV H - Injection

14. Horizontal painting bump Use (mostly) existing KSW magnets – Relocate one magnet from 1L1 to 16L1 09/11/201114Review on PSB 160 MeV H - Injection

15. Instrumentation Systems installed locally in injection straight needed to commission and operate injection – Beam loss monitors – Waste beam dump current monitoring (H 0 and H - ) – Foil signal monitoring – Beam screen at injection point – Foil imaging system Will also rely on other systems – BPMs in TL and rings, BCTs, SEM grids, ring BLMs,... 09/11/201115Review on PSB 160 MeV H - Injection

16. Present situation 09/11/201116Review on PSB 160 MeV H - Injection

17. After upgrade 09/11/201117Review on PSB 160 MeV H - Injection

18. Particular features “Slow” chicane fall time of 5 ms – Allows active compensation of optics perturbation using trim quadrupole circuits – Rely on fast decay of H painting bump to remove beam from foil Waste H 0 /H - dump integrated into BSW4 magnet – No space to add 2 nd foil and extraction septum for external dump No active vertical “painting” system – Target emittances to be accomplished by controlled dipole (offset) and betatron mismatch – Discussions on alternatives ongoing (kicker in injection line...?) Chicane dipoles aligned with zero angle wrt circulating beam – Aperture at septum, dump and for stripping foil unit integration 09/11/201118Review on PSB 160 MeV H - Injection

19. Summary Addition of H - system to existing PSB challenging – Space constraints in available straight section – 4 superimposed rings complicates integration further Resulted in a number of design compromises – Short, strong chicane dipoles – Optics perturbations from strong chicane dipoles actively compensated with trim quadrupole circuits – Beam acceptance limited at specific locations – Integration of waste beam dumps into 4 th chicane dipole Chosen to have “slow” chicane fall time – Allows tracking of optics correction – Relies on painting bump fall to quickly remove beam from foil System has to provide wide variety of beam types 09/11/201119Review on PSB 160 MeV H - Injection

20. 09/11/201120Review on PSB 160 MeV H - Injection

21. Target parameters for injection LHC intensity 3.25e12 total per ring CNGS intensity 2.5e12 total per ring Uncontrolled Beam loss target – few 1e-3 total (max 50 W at 160 MeV)