Ionization Beam Loss and Cryocatcher (Collimator) for SIS100COLMAT

1. Ionization Beam LossandCryocatcher (Collimator) for SIS100COLMAT task meeting23.3.2010P. Spiller and Lars Bozyk

2. Introduction Ionization Beam Loss Mechanism Ion Catcher SIS100 lattice Loss distribution Catcher efficiency Ionization Beam Loss Simulation in a SIS100 Cycle Loss rates Power deposition by losses Cryocatcher design Summary Content

3. P.Spiller, 2001 Ionization Loss Mechanism Projectile Ionization dominates at SIS Energies for low charged Ions U28+ + R0 U29+ + R0 + e-

4. All kinds of beam loss produces a local pressure rise via ion stimulated desorption ~ 3...30∙103 molecules / Ion ┴~100 molecules / Ion Probability for beam ion ionization depends on residual gas pressure, ionized ions get lost Losses drive a pressure bump Self amplification can develop up to complete beam loss Maximum number of particles is limited Initial losses dominate the whole cycle Ionization Loss Mechanism

5. Controlled catching of ionized ions on low desorption surfaces Ions hitting the wall release adsorbed gases and produce a local pressure bump Desorption yield is lowest for perpendicular incidence Most ionized ions are caught by ion catcher in SIS100 Significant reduction of gas desorption  Residual gas pressure dynamics is stabilized  Lower total ionization loss Activation and radiation damage of magnets by ionization beam loss is reduced SIS100 Ion Catcher is part of the EuCARD WP8: ColMat Ion Catcher

6. SIS100 lattice has been optimized to reach a maximum catching efficiency Loss distribution is strongly localized between the quadrupoles where the ion catcher will be installed SIS100 Lattice U28+ U29+

7. Losses normalized to one arc, U28+ U29+ 99.6% catching efficiency SIS100 Ionization Loss Distribution Logscale!

8. SIS100 Ionization Loss Distribution

9. SIS100 Ionization Loss Distribution

10. SIS100 Catching Efficiency

11. Injection of 4 x 1.5∙1011 U28+ particles Base pressure 5∙10-12 mbar, residual gas Hydrogen dominated 10 K on all cold surfaces, effective pumping speed 74 m³/s Desorption yield: 25500 (dE/dx scaled)(54.7% CO, 22% H2, 16.4% CO2, 4.1% CH4, 2.8% N2) Low energetic desorption yield: 5 (Target Ionization) Systematic losses at injection (4%), and extraction losses (2%) SIS100 Cycle Simulation

12. SIS100 Cycle Simulation

13. SIS100 Cycle Simulation – Loss Rates

14. SIS100 Cycle Simulation – Loss Rates Measurement of electrical current on catcher:Signal for high ionization losses

15. SIS100 Cycle Simulation – Loss Power

16. Cycle at increased inital pressure (10-10 mbar) Electric current measurement generates an interlock, when increasing losses exceeds a threshold SIS100 Cycle Simulation – Loss Cycle

17. SIS100 Qaudrupole Cryostat Cryocatcher

18. Cryocatcher 80 K 5 K 80 K 5 K 5 K

19. Cryocatcher – Temperature Simulation

20. Prototype Catcher Prototype Cryostat and „Cold Mass“

21. Prototype Catcher Geometries

22. Cryocatcher – FLUKA-Simulation Simulations by M.Kirk show similar results

23. Losses due to ionization are controlled at well defined and known positions Cryocatcher are located at these positions to minimize desorption Ionization losses will be monitored to trigger an interlock Cryocatcher reducesradiation damage and activation of neighboring magnets Summary

24. Project Status and Outlook • PhD Student hired • Beam time proposal made and SIS beam time assigned • Tendering process is running until end of April 2010 • Expected delivery of components: July 2010 • Electroplating at GSI: September 2010 • Set-up at the experimental area completed: March 2010 • Test and measurements with SIS beam: summer 2010