MuCool RF Workshop-Fermilab 107/07/2009 Muons, Inc. Dielectric-Filled RF Cavities Milorad Popovic FNAL

MuCool RF Workshop-Fermilab 207/07/2008 Muons, Inc. A Tale of Two Cavities Best of Times-Worst of Times Cu/Steel ceramics Vacuum/H/He For HCC Vacuum Cavity

MuCool RF Workshop-Fermilab 307/07/2008 Muons, Inc. Motivation To fit pressurized cavities in HCC, size of cavity has to be reduced 800 MHz (from Katsuya) Maximum RF cavity radius = 0.08 m, (pillbox cavity 0.143) Radius of effective electric field (95 % from peak) = 0.03 m 400 MHz: Maximum RF radius = 0.16 m (pillbox cavity 0.286) Radius of effective electric field = 0.06 m Optimum electric field gradient = 16 MV/m For Pill Box Cavity, resonant frequency is

MuCool RF Workshop-Fermilab 407/07/2008 Muons, Inc. HCC Canal has High Magnetic Fields No Magnetic Materials Acceleration should be Continues Dielectric Loaded RF Cavities Cu/Steel ceramics Vaccum/H/He

MuCool RF Workshop-Fermilab 507/07/2008 Muons, Inc. HCC Concept Central Orbit and Beam EnvelopeSet of Coils Basic Building Block can be Cavity + Coil

MuCool RF Workshop-Fermilab 607/07/2008 Muons, Inc. MANX + RF ? Detecto rs Cavity + Coil Cryostat Vessel Feedthroug hs Power in Signals out MICE will have

MuCool RF Workshop-Fermilab 707/07/2008 Muons, Inc. Ceramics can play additional role, making volume of Hydrogen smaller and making cavity stronger so the walls do not have to be as thick as without ceramics. RF power can be fed using loop between two rings. Cavities can be put next each other so the side wall can be made thin We should do experiments in the MTA 201MHz (with solenoid?) 805MHz with solenoid!

MuCool RF Workshop-Fermilab 807/07/2009 Muons, Inc. Power dissipation = kW Q = Re_eps=9.5, Im_eps= Power dissipation = kW Q = Re_eps=9.5, Im_eps=0.0 Lossless Dielectric ~400MHz-16MV/m, Q, Power

MuCool RF Workshop-Fermilab 907/07/2009 Muons, Inc. PAC09 Paper

MuCool RF Workshop-Fermilab 1007/07/2009 Muons, Inc. Did Not Get FIRM NAME: Muons, Inc. RESEARCH INSTITUTION: Fermi National Accelerator Laboratory Milorad Popovic, subgrant PI ADDRESS: 552 N. Batavia Ave. Batavia, IL ADDRESS: Loss tangent tan d = 1/Q dielectric -1/Q air Loss tangents of specially formulated alumina with TiO 2 have been reported to be close to sapphire at 1e-5. So it is easy to see that today’s ceramics may be used in this novel idea without suffering a great deal in cavity Q at low frequencies. The other problem with ceramics in vacuum with beams is that of surface charging of the ceramic. And again, much work has been done in coatings, from Chromium Oxide to TiN to, more recently, ion implantation Air gap between the dielectric and metal plates will be one of the issues that must be tested experimentally But Main Issues did not go away

MuCool RF Workshop-Fermilab 1107/07/2009 Muons, Inc. Main Issues Ceramics, Loss Tangent Surface coating Dielectric Cooling/Tuning Liquid Geometric/Power Optimization RF and Mechanical Engineering ~50k$ + 1FTE to Start

MuCool RF Workshop-Fermilab 1207/07/2009 Muons, Inc. Other Applications (Vacuum Cavities) May be we can use this type of cavity for Neuffer’s Phase Rotation Canal. This was Cary Yoshikawa suggestion. The canal needs many cavities in range from ~300 to 200MHz. We can use, let say two sizes of Pill Box Cavity (same size different dielectric!) and adjust frequency in between using different iner radius, re-entrant nose cones!

MuCool RF Workshop-Fermilab 1307/07/2009 Muons, Inc. Cavities for Neutrino Factory Schematic of the Neutrino Factory front-end transport system. Initial drift (56.4 m), the varying frequency buncher (31.5m), The phase-energy (  -  E) rotator (36m), a cooling section. (A 75m cooling length may be optimal.) ParameterDriftBuncherRotatorCooler Length (m) Focusing (T) (ASOL) Rf frequency (MHz)360 to to Rf gradient (MV/m)0 to Total rf voltage (MV)

MuCool RF Workshop-Fermilab 1407/07/2009 Muons, Inc. Vacuum Open Pill Box in Strong Magnetic field, Vacuum Cavity

MuCool RF Workshop-Fermilab 1507/07/2009 Muons, Inc.

MuCool RF Workshop-Fermilab 1607/07/2009 Muons, Inc.

MuCool RF Workshop-Fermilab 1707/07/2009 Muons, Inc. t(ns)E(MV/m)ConvInsu

MuCool RF Workshop-Fermilab 1807/07/2009 Muons, Inc. Try to Establish Modeling Capability Locally (E-Cool people, Lionel Prost)

MuCool RF Workshop-Fermilab 1907/07/2009 Muons, Inc. Geometry for electrostatic calculations Based on Leopold et al.: Optimizing the Performance of Flat-surface, High-gradient Vacuum Insulators Length: 12 cm I/M = 2 Upstream electrode = -100 kV Downstream electrode = 100 kV  r = 7 Equipotentials:  U = 4 kV I M

MuCool RF Workshop-Fermilab 2007/07/2009 Muons, Inc. Electron trajectories calculations I M Trajectory for an electron generated at the metal ‘surface’ Trajectory for an electron generated at the insulator ‘surface’ Initial conditions: keV (program does not accept 0) - No transverse velocity - R ini = 0.99 cm (bore radius is 1 cm)

MuCool RF Workshop-Fermilab 2107/07/2009 Muons, Inc. SuperFish

MuCool RF Workshop-Fermilab 2207/07/2009 Muons, Inc. Main Issues Ceramics, Loss Tangent Vacuum Surface Coating Dielectric Cooling/Tuning Liquid Geometric/Power Optimization Design, I/M Ratio RF and Mechanical Engineering ~50k$ + 1FTE to Start

MuCool RF Workshop-Fermilab 2307/07/2009 Muons, Inc. What is Next, 5-Years Plan …We will also accomplish sufficient hardware R&D (RF, magnets, and cooling section prototyping) to guide, and give confidence in, our simulation studies. In order to produce a practical helical cooling channel, several technical issues need to be addressed, including: magnetic matching sections for downstream and upstream of the HCC a complete set of functional and interface specifications covering field quality and tunability, the interface with rf structures, and heat load limits (requiring knowledge of the power lead requirements) To prepare the way for an HCC test section we would: Develop, with accelerator designers, functional specifications for the magnet systems of a helical cooling channel, including magnet apertures to accommodate the required rf systems, section lengths, helical periods, field components, field quality, alignment tolerances, and cryogenic and power requirements. The specification will also consider the needs of any required matching sections. Perform conceptual design studies of helical solenoids that meet our specifications, including a joint rf and magnet study to decide how to incorporate rf into the helical solenoid bore, corrector coils, matching sections, etc. The projected funding for the 5-year program proposed here..

MuCool RF Workshop-Fermilab 2407/07/2009 Muons, Inc. (near)FUTURE o In week or two I hope, DC results with existing dielectric o NuFact09-This Summer I hope, RF(low power) results with low loss dielectric (Vacuum Cavity)

MuCool RF Workshop-Fermilab 2507/07/2009 Muons, Inc. Test Cavity

MuCool RF Workshop-Fermilab 2607/07/2009 Muons, Inc.

MuCool RF Workshop-Fermilab 2707/07/2009 Muons, Inc.