1. Chris Smith Booster RF Cavity Upgrade Contents: The Booster Existing RF Cavities Why Upgrade? New Cavities Prototype Plans University Involvement Prototype Schedule To The Future

2. Chris Smith The Booster Booster accelerates 400 MeV protons from LINAC to 8 GeV for injection to MI, MiniBooNE Proton acceleration cycle rate ultimately limited by cycle time of magnets: 15Hz Currently, average cycle time limited to ~3Hz Improvements to extraction septum magnets and power supply will permit cycle time 7.5Hz However, solely increasing repetition rate leads to increased proton losses

3. Chris Smith Booster RF Cavity 18 RF Cavities operate in Booster Run at 53MHz, producing ~55kV Beam pipe aperture: 2.25 inches Cavity frequency controlled by 3 ferrite loaded variable inductors, “tuners” 150 kW power amplifier mounted on top of cavity

4. Chris Smith Why Upgrade? Existing cavities are the smallest aperture in the machine Consequently, cavities and power supplies become activated (~50 mrem/hr at 1ft) The RF power supplies are the highest maintenance components in the machine Need to wait for radiation levels to drop before people can fix them This is one of the largest causes of Booster downtime This problem can only get worse as proton intensity increases!

5. Chris Smith New Cavities Originally proposed as part of new Proton Driver Cavities have larger beam pipe aperture: 5 inches Only minor design modifications to existing cavities Expected to increase proton intensity by few % by reducing downtime due to component activation Also allows for higher intensity (10-20%?) without incurring unreasonable activation due to beam loss Mechanical prototyping to date carried out on an existing damaged Booster RF cavity: Modified cavity was run at high power, 53MHz using 2 Booster tuners and 1 MI tuner

6. Chris Smith Prototype Plan University interest in Booster Upgrade has helped accelerate and define project Two new prototypes are now to be constructed, predominantly from old cavities Drawings for 10 cavity parts and 10 tooling pieces (required for assembly) have been finalized and distributed to universities Some (radioactive) parts will still be machined at FNAL Assembly and testing carried out at FNAL

7. Chris Smith Project People Appointed in early February: Project Manager  René Padilla (FNAL) Design Engineer  Mike May (FNAL) Testing and qualification  John Reid (FNAL) University Machine Shop Coordinator  Bill Sands (Princeton)

8. Chris Smith University Involvement 6 Institutions involved MINOS: Caltech, Texas, Tufts MiniBooNE: Indiana, Nevis, Princeton Proposal for MINOS institutions to fabricate the required quantities for 12 of 20 drawings accepted Fabrication cost to FNAL is ~20% expected by exploiting university machine shop “deals” Main cost to FNAL is for materials Remainder of parts to be completed by MiniBooNE institutions or FNAL? (Or MINOS…)

9. Chris Smith Prototype Schedule Very aggressive! Ultimate goal is to have the new cavities tested and installed during the summer shutdown (starting 28 th July and lasting for 6 weeks) Finer details are still being worked out – expect a week-by-week schedule in a few days... Some issues are still unclear: will old tuners suffice? Fabrication:now – mid-Apr Assembly:mid-Apr – end of June Measurements/Testing:July Installation:Aug – Sept

10. Chris Smith To The Future… Collaboration of universities with FNAL for prototype project is “overkill” Useful to cultivate working relationship for larger task of fabricating 20 large aperture Booster RF cavities Important to get people involved now to ensure universities can play active role in any future production By universities taking on a large fraction of the work, substantial cost reductions can be made!