Superconducting Cavities Development at Fermi National Accelerator Laboratory Dmitri Denisov DIET Federation Roundtable, Washington DC, April

Fermi National Accelerator Laboratory is the Department of Energy National Laboratory, created in 1967 to build particle accelerators for fundamental studies of matter and energy  Fantastically successful program over more than 40 years  Complex of various accelerators built  Including first superconducting accelerator  Discovered new fundamental elements of matter bottom and top quarks, tau neutrino  1000’s of experiments performed which contributed to our deep modern understanding of Nature  ~20,000 scientists from all over the world participate in the experiments  ~1,700 employees, ~$400 million budget  Exciting future program of studies of elementary particles  Plan to participate strongly in the ILC in Japan Denisov, DIET, April

Superconducting Cavities is the Heart of the ILC ILC goal is to accelerate electrons to enormous energy of 250 GeV per beam Almost a million times more than the mass of the electron! Beam is moving in the vacuum pipe and each cavity “pushes” it adding more and more energy Accelerating electric field is ~30 million volts per meter! Such fields could only be created by specially designed cavities Oscillations of electric current in the cavities creates heat Superconductivity (no resistance to electric current) is crutial to reduce energy losses during cavities operation Fermilab has excellent experience in designing and building superconducting cavities Denisov, DIET, April km long 3

Assembly of Superconducting Cavities at Fermilab Cavities electro polishing tool Chemical polishing setup High Pressure Washing Machine  Cavities are made from niobium which exhibits superconductivity when cooled to liquid helium temperature of ~2 degree Kelvin  Only 2 degrees above absolute zero temperature!  Manufacturing is a complex process to create very high accuracy device with very uniform surface with no imperfections  Otherwise high field will create “sparks”!  Special clean rooms and tools are developed at Fermilab to create ILC-type cavities Denisov, DIET, April

Cryomodule Assembly at Fermilab Cavity assembly in Class 10 clean room Cold mass being installed in vacuum vessel Cryomodule complete Cold mass with cavities  Cavities are assembled with beam pipe, wrapped in super insulation and then inserted into vacuum vessel called cryomodule  Such cryomodules, about 10m in length, are then installed in the ILC underground tunnel Denisov, DIET, April

Team of Cavities Experts at Fermilab Large team of people works at Fermilab on the developments of superconducting cavities. Scientists and engineers from Fermilab, Argonne National Laboratory, Jefferson Laboratory and KEK (Japan) are involved Denisov, DIET, April

Improvements in Cavities Design Continue  Recently experts working on ILC cavities at Fermilab improved “Q” factor (quality factor) which determines power losses in the cavity by a factor of ~4  It will provide a factor of two savings in cryogenic system (which keeps cavities cold) including equivalent reduction in the long term operational expenses (electricity) Denisov, DIET, April 2015 Standard ILC/state-of- the art preparation Record quality factor after nitrogen doping 7 In October 2014 first cryomodule satisfying ILC specifications has been assembled and tested at Fermilab 31.5 million volts per meter required for ILC reached!

Summary  Fermi National Accelerator Laboratory has 40+ years of experience in building and operating accelerators and particle detectors  Many fundamental discoveries, including fundamental building blocks of matter b quark and top quark  Tremendous progress in technology including developing superconducting magnets which are now widely used in industry, transportation and medicine  Fermilab, together with other US National Laboratories and scientists from Japan, developed superconducting accelerating cavities for the ILC  Production of superconducting cavities similar to ILC is planned at Fermilab for US based projects  We are looking forward for Japan to host the ILC  Fermilab will participate in the ILC construction and the experiments at the ILC – we have deep expertise in both areas Denisov, DIET, April

Accelerators are the Tools to Study Nature Accelerators are “giant microscopes” to study extremely small objects ~ cm Particle Wavelength=h/E  Electron microscope is better than optical! Accelerators are “converters of energy into mass” E=mc 2 Objects with masses up to Mass = 2E beam /c 2 could be created E beam Mass E beam Cell Proton Electron beam Positron beam Denisov, DIET, April

Accelerators and Experiments at Fermilab Modern accelerator and experiments are at the edge of the technology Many kilometers of tunnels with complex equipment Detectors with 1000’s of tons in weight and 10’s of millions of detection channels 6,000 acres dedicated site near Chicago Denisov, DIET, April

Technology Progress Development of superconducting cavities will bring many new technologies to life from “table top” coherent light sources to burning nuclear power plants fuel and other applications we don’t even dream today about Denisov, DIET, April 2015 Development of superconducting magnets for Fermilab’s accelerators in 1970’s and 1980’s paved the way for large scale use of superconductivity in industry and medicine: NMR scanners, magnetic levitation trains, lossless power transmission lines and many others 11

Tests at Each Step of Production  After production each cavity is tested at liquid helium temperature  To assure it satisfies all ILC specifications  All major parameters of the cavities are tested  Accelerating field  Energy losses  Temperature map  Scientists and engineers from Fermilab, Argonne National Laboratory, Jefferson Laboratory and KEK (Japan) are involved in the production and testing of the cavities Cavity is ready for cooling Inside test cryostat Vertical cryostats with cavities inside Denisov, DIET, April

Projects with Superconducting Cavities  Linear Coherent Light Source – powerful source of coherent X-rays for studies in biology, medicine, solid state physics  Acceleration of electrons using superconducting cavities  Fermilab is building ~20 cryomodules for LCLS-II project at Stanford Linear Accelerator Center (California)  New 1 GeV linear accelerator of protons at Fermilab  To increase intensity of the accelerator complex by a factor of two  Superconducting cavities can accelerate protons as well as electrons Denisov, DIET, April

Assembled Cryomodule Satisfies ILC Specifications ILC Milestone = 31.5 MV/m  Main parameter of the cryomodule is accelerating voltage per meter  In October 2014 first cryomodule satisfying ILC specifications has been assembled and tested at Fermilab – 31.5 million volts per meter reached! Denisov, DIET, April