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Mini-BooNE & NuMI: Primary Beams Overview

Detailed information on Mini-BooNE and NuMI primary beam parameters, targeting parameters, design improvements, monitoring systems, commissioning schedule, beam constraints, loss limits, and control methods.

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Mini-BooNE & NuMI: Primary Beams Overview

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  1. Primary Beams for Mini-BooNE & NuMI 18 March, 2002 Mini-BooNE inputs from Craig Moore and Al Russell Includes NuMI inputs from Bob Ducar, Peter Lucas, John Johnstone and Alberto Marchionni

  2. Very Different Primary Energies –but Common Goals MiniBooNE: Primary Beam Momentum- 8.9 GeV/c from Booster. Intensity goal - 5x1012 ppp at 5 Hz cycle rate. Goal: ∫ Protons = 5 x 1020 p/year - An annual flux > than the sum of all previous FNAL Booster operation over 30 yrs. NuMI: Primary Beam Momentum- 120 GeV/c from Main Injector. Intensity Goal: to 4x1013 ppp at 1.87 sec. cycle rate. An annual beam power comparable to the sum of all previous Fermilab fixed target operation.

  3. Mini-BooNE Primary Beam - Overview Primary Beam Momentum- 8.9 GeV/c Spill length 1.6 microseconds Intensity - 5x1012 ppp Rep rate 15 Hz (5 Hz Beam) 2x107 seconds/yr ∫ Protons = 5 x 1020 p/year Invariant Emittance 20 Pi mm.mr – 95% beam envelope Targeting Parameters: • Target 9 mm diameter cylinder • 99% spot size < 8mm diameter • Targeting angle and beam divergence < 4.6 mr • Position stability < 1 mm The greatest concern – achieving essential radiation level improvements for Fermilab Booster –discussed in Radiation Protection Session

  4. Schematic Layout of MiniBooNE Beamline

  5. Design Process Improvement: MiniBooNE Primary The most significant design improvement since original design efforts has been a change to much larger aperture dipoles and quads (considerable magnet refurbishing, but use of existing magnets) Early Design: EPB dipoles (37 mm aperture) and 3Q quads (75 mm) Upgrade Design: 6-3-120 dipoles (75 mm aperture) and LEP quads (125 mm) The following figures show an original beam transport envelope plot leading to the early stage aperture upgrade.

  6. Vertical Clearance – 99% EnvelopeBEFORE Improved Apertures

  7. MiniBooNE Beam Envelope and Apertures - Horizontal

  8. Mini-BooNE Beam Monitoring - Electronic Berm By measuring the difference in two well calibrated intensity monitors at the beginning and end of beamline, can detect losses and abort beam. If this is done in a failsafe manner, can substitute for some shielding.or other electronic radiation monitoring. BooNE is looking to measure a 2% loss averaged over several pulses or >6% over 1 pulse. Significant improvement over previous similar usage at Fermilab

  9. Other Features – BooNEPrimary • Much standard instrumentation • Multiwire profile SEM monitors • Beam Loss Monitors • BPM’s (noninteracting position monitors) • < 0.5 mm resolution for targeting units • Power supply stability upgrades (FNAL standard • packages) • Autotune beam position control – very successful in • several previous uses.

  10. Schedule: BooNE Primary Commissioning • Beam enclosures complete • Technical component installation ongoing & well advanced. • Project initial beam commissioning effort by • June ‘02

  11. NuMI Primary Beam

  12. Some NuMIPrimary Beam Parameters • Highest possible intensity from Main Injector • Near term projection ~ 2.5x1013 protons per pulse, 120 GeV at 1.87 sec. cycle time (Goal to 4x1013 ppp) • Kicker extraction 5 batches each of 1.6 µsec • Simultaneous operation with PBAR stacking • Targeting parameters • Beam sigma 0.7mm (h) x 1.4mm (v) • No dispersion & minimal divergence at target • Position control ~ 0.25 mm; angle to 70 µrad.

  13. NuMI Facility(elevation view)

  14. NuMI Primary Beam Constraints • Some significant NuMI primary beam constraints. • Very high primary intensity ~ 80% of Main Injector capability. • Transport of this intense beam in a tunnel located in the protected groundwater aquifer region. Effective shielding not a practical option. • Initial beam transport design constraints imposed by long drift region (430’) from glacial till to pre-target tunnel in mined dolomite. • Solution accomplished by a rigorous approach for primary beam control involving transport design, power supply stability, instrumentation usage, control algorithms and comprehensive beam permit system.

  15. Beam Loss Model Geometry

  16. Beam Loss Limits from MARS14 Calculations • Results indicate average beam loss fraction limits of 110-4 to 610-3 of the high intensity primary beam flux, dependent on tunnel location. A loss fraction limit of 10-6 of the beam is seen in lined regions of the carrier tunnel. However, in this region geometry constraints preclude direct primary beam loss except for fault modes such as a vacuum pipe collapse or a magnet coil failure. • Maintaining average beam loss fraction levels at ~ 10-4 or less is also well matched to need for control of component residual activity. Sustained localized beam loss of this level leads to ~ 150 mrem/hr readings on near magnet outside surfaces.

  17. System for Beam & Beam Loss Control • Most important is a well functioning beam transport line • Apertures / optics design enabling clean beam transmission, minimal sensitivity to normal variations of beam parameters - emittance, momentum spread, bunch rotation, etc. • Quantitative understanding of Main Injector extracted beam parameters. • Power supply stability • Design for long term ~ 60ppm for major bends, 200ppm for smaller bends. (One supply at these limits gives < 1 mm change along transport, 0.25mm for targeting.) Pulse to pulse variations are much less. • Comprehensive loss monitor coverage • Sensitivity to all beam loss modes, redundancy of loss coverage, continuous checks for loss monitor function, calibrated response and dynamic range for fractional beam loss from 10-5 of the high intensity beam to a full beam loss

  18. System for Beam Control (cont) • Capability for precise and rapid correction of beam position problems due to system drifts • AUTOTUNE beam position control • Comprehensive alarms and limits monitoring • Comprehensive beam permit system to preclude beam extraction to NuMI when an identifiable problem exists • Beam test prototyping of hardware ongoing All of these are patterned after previous successful efforts.

  19. Characterization of Main Injector Beam Parameters D. Jensen, G.M. Koizumi, V. Makeev, A. MarchionniFermilab B.C. Choudhary CalTech • Measurements of transverse and longitudinal beam profiles in MI as a function of beam intensity • Additional measurements of momentum spread in P1 • Plan for the future

  20. Bunch length from Resistive WallMonitor @flattop Observed variations of ~ 10%

  21. Bunch Length during Bunch Rotation From RTD720 Average 2 (ns) 2.5 ms 2.5 ms Time (t=0.188 ms) BLMON

  22. Baseline Beam Envelope with Apertures

  23. Improved Beam Envelope with Apertures

  24. Beta & Eta Functions:Projected Design

  25. NuMI Primary Summary • A significant number of essential improvements to NuMI primary design and planning have been seen over recent months – to address some severe design constraints. • Efforts are ongoing to incorporate these into the project plan. • Technical construction funding available Oct.’02. Priority then moves to building systems. • Major installation ramp up late ’03 when Service Bldg. and tunnel outfitting complete. • Beam commissioning late ’04 – early ’05.

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