Main Injector Collimation: Conceptual Design Summary

1. Main Injector Collimation:Conceptual Design Summary Bruce C. Brown Review of MI Collimation Concepts 30 June 2006

2. MI Collimation Concepts • Booster and MI8 Collimation designed for 5 x 1012 protons/pulse at 10 Hz or 64 kWatts of beam power from Booster • When slip-stacking for both NuMI and PBar Production we expect 11 Booster cycles per 2.2 Seconds with about 5.5E13 total beam or 32 kWatts of beam power at 8 GeV or 480 kW at 120 GeV in Main Injector • Losses are mostly at or near 8 GeV. Losses from slipstacking of ~ 5% are expected. Bruce C. Brown, Fermilab/AD

3. MI Collimation Concepts • Simulation Effort has focused not on exact MI properties (not known) but on properties as understood using techniques which permit study of sensitivity using parameter variation. • The simulation is compared (successfully) to operation with respect to • Time structure of beams after 1 MV capture • Time structure of loss (beam current, loss mon. • Spatial structure of loss – longitudinal, horizontal, vertical, and momentum. Bruce C. Brown, Fermilab/AD

4. MI Collimation Concepts • Loss for all operation includes • Transition Loss • Extraction Loss • Loss from slipstacking operation has several components: • 8 GeV Lifetime before and after 1 MV capture • Beam captured at 1 MV is other buckets • DC Beam outside of separatrix for any bucket. • Collimation System design should: • Address DC Beam with high efficiency • Should mitigate other loss components Bruce C. Brown, Fermilab/AD

5. MI Collimation Concepts • Radiation Goals for MI Collimation • Hands-on maintenance for whole Main Injector • Hands-on maintenance for collimator systems • ALARA for all regions with particular concern for ECOOL electron beamline components. • Satisfy all Radiation Safety concerns for MI • Ground water, air activation, etc (not restrictive). • Minimize residual radiation exposure by use of marble to shield activated components where possible. • Massive collimator to contain activated materials and thereby avoid surface (sump) water restrictive limit. Bruce C. Brown, Fermilab/AD

6. MI Collimation – How Maximum Collimator Size in MI Straight Drawing by Vladimir Sidorov Bruce C. Brown, Fermilab/AD

7. MI Collimation – How MI Collimator Possibility – 48” x 48” steel- 60” long 19.4 Ton weight – collimates ~few kW Drawing by Vladimir Sidorov Bruce C. Brown, Fermilab/AD

8. MI Collimation Concepts • Collimator Design Issues: • Design Loss • Total Weight Limit • Density at shower peak (therefore cost) • Size Constraints • Move Collimator Externally as Block? • Provide Horizontal Motion for whole collimator but vertical Motion for central core? • Fixed Collimator -- Steer with Trim Dipoles? • Collimation Design Issues: Configuration Options -- Bruce C. Brown, Fermilab/AD

9. MI Collimation Concepts Bruce C. Brown, Fermilab/AD

10. MI Collimation Concepts Tentative Conclusions: • Slipstacking simulation is good enough • Loss simulation matches observations • Provide Collimation at MI22/MI30. • Mechanical design constraints are mostly independent of layout. Weight and size is main constraint. • Configuration Optimization will require further simulation interacting with design. Bruce C. Brown, Fermilab/AD

11. MI Collimation Concepts Uncertainties: • Can fixed apertures plus trim dipoles provide sufficient flexibility? • Does a collimator which can be precisely aligned need enough motion hardware that it might as well be remotely controlled? • We have focused on MI22 but MI32 has higher residual radioactivity. What will permit us to choose between these possible collimation locations? • How do we maximize our impact on other loss mechanisms? • How much loss do we design to manage. Can we justify the cost of Copper or Tungsten ($100/lb) or complications from lead (mixed waste) or Depleted Uranium (Plutonium production)? Bruce C. Brown, Fermilab/AD

12. MI Collimation Concepts Other Things We Observe: • Should we add trim quads to allow half-integer stop band correction in two planes and two phases? The magnet selection for placing Main Ring Quadrupole in the Main Injector placed strong IQB’s on the focusing bus and weak IQB’s on the defocusing bus to minimize the half-integer stop band width. But this selection was done at high field. The distribution of 8 GeV strengths has not benefit from this and is much wider than the 120 Gev strength distribution. • The new MI BLM system should permit much better study capability as well as very much better monitor capability. • Chromaticity effects may interact strongly with loss creation and especially with loss distribution. Understanding this may fully employ the new loss monitor capability. • The constraints in the regions we propose for collimation include orbit considerations for special operations: • Radial aperture for resonant extraction at 120 GeV • Radial aperture for transferred beam and counterwaves at both MI22 (or MI32) and at MI30 to permit transfers to/from Recycler. We think that we have provided for these constraints but great care will be required. Bruce C. Brown, Fermilab/AD

13. MI Collimation Concepts We have not dealt with: • Is collimation system proposal compatible with SNuMI era transfer line proposal? (Charge #3) • We have noted that the requirements we address – losses from MI Slip-stacking – will not be relevant in SNuMI era. • Both MI62 and perhaps MI22 and MI32 will have new collimation possibilities in that era. • The proposed lattice modifications can be ramped on after a transfer if that facilitates compability. • We have not proposed any instrumentation additions for this effort. We are not to that advanced stage. But in the ring, the MI has lots of instrumentation. Bruce C. Brown, Fermilab/AD

14. MI Collimation Concepts Conclusions: • Localized losses as observed by residual radiation have been at unsustainable levels at a few MI locations at times since 2004. • Stacking, including Slipstacking injection is inherently lossy and any Booster beam quality issues will make things worse. • A well justified system for localizing slipstacking losses is within reach. Mechanical design effort to guide final choices is appropriate. • Localization for other loss mechanisms will surely be partially addressed by these collimation systems. Bruce C. Brown, Fermilab/AD

15. MI Collimation Concepts Bruce C. Brown, Fermilab/AD

16. MI Collimation Concepts Review of Main Injector Collimation Concepts [20 min] Bruce Brown Introduction -- Collimation Needs and Capabilities [20 min] Ioanis Kourbanis Losses and Slip-Stacking and Kiyomi Seiya in NuMI Era [20 min] Nikolai Mokhov Loss limits for collimation within the Main Injector Tunnel [60 min] Alexandr Drozhdin Simulation of losses from Slipstacking operation of Main Injector [1 hr] Lunch Break [30 min] Bruce Brown Beam Loss measurements -- Loss Monitor and Residual Radiation Results [20 min] Dave Johnson Creating Dispersion for collimation in MI30 Straight Section [40 min] Alexandr Drozhdin Simulation of Loss Control with Collimators with or without Lattice Changes [20 min] Bruce Brown Summary of options and concerns Bruce C. Brown, Fermilab/AD

17. MI Collimation – How Some MI8 Collimator Costs (4 collimators) Bruce C. Brown, Fermilab/AD