Normal Conducting Magnets Practical Work @ CERN Normal Conducting Magnets Thursday 25th & Friday 26th February 2016, 9:00 – 17:00

Outline Brief introduction to accelerator magnets Program and Organization of Magnet Practical Works Magnet Technology, Production and Testing Magnetic Measurements

Magnetic Field in Particle Accelerators Particle accelerators: control over moving (charged) particles  need action against mechanical inertia Equilibrium in the transverse plane: Centrifugal force vs. Lorentz force F = mv2/ρ F = q(E + vΛB) Electrical field quickly shows limits to drive particles with high mass (hadrons) and/or velocity  qvB = mv2/ρ Magnetic rigidity: Bρ = mv/q “A charged particle with constant velocity crossing constant field follows a circular trajectory”

Introduction to Magnets A magnetomotive force creates a magnetic flux iron core coil magnetic field NI = R x  Magnetomotive force is essentially used in the air gap air gap current Flux = Field x Section = B x A (“Field” is actually “Magnetic flux density”) Courtesy D. Tommasini

Introduction to Magnets Basic principles : constitutive equations Introduction to Magnets R = length /(electrical conductivity x section) R = length/ (magnetic permeability x section) NI =  H∙dl (Ampère’s law) R x (Hopkinson’s law) B = 0rH µ0 = 4∙10-7 Tm/A H can be interpreted as “magnetizing pressure” In ferromagnetic materials small H creates high B liron NI lair Courtesy D. Tommasini

Dipoles Purpose: bend or steer the particle beam Equation for normal (non‐skew) ideal (infinite) poles: y= ±r (r = half gap height) Magnetic flux density: By= a1= B0 = const. ‘Allowed’ harmonics: n = 1, 3, 5, 7, ... (= 2n pole errors) Courtesy T. Zickler

Dipoles Courtesy T. Zickler

Quadrupoles Purpose: focusing the beam (in one plane) Equation for normal (non‐skew) ideal (infinite) poles: 2xy= ±r2(r = aperture radius) Magnetic flux density: By= a2x ‘Allowed’ harmonics: n = 2, 6, 10, 14, ... Courtesy T. Zickler

Quadrupoles Courtesy T. Zickler

Sextupoles Purpose: correct chromatic aberrations Equation for normal (non‐skew) ideal (infinite) poles: 3x2y ‐y3= ±r3 (r = aperture radius) Magnetic flux density: By= a3(x2‐y2) ‘Allowed’ harmonics: n = 3, 9, 15, 21, ... Courtesy T. Zickler

Sextupoles Courtesy T. Zickler

Program and Organization of Practical days 8 to 10 participants Hands-on practical work in CERN laboratories Guided by CERN magnet experts Split into two half-day sessions Magnet production and testing Magnetic measurmements

Magnet Production and Testing Introduction to magnet production Materials for magnets Magnet components Manufacturing technologies Testing and measurement techniques Practical work in magnet test facility (Meyrin site, bldg. 375) Participants will perform certification tests and measurements on recently built magnets Measurements on systems and apparatus using formulae learned during the theoretical courses Visit the CERN normal conducting magnet prototype workshop “NORMAPRO” (Prévessin site, bldg. 867) Yoke manufacturing Coil winding and impregnation

Magnet Production Coil winding Yoke manufacturing Coil impregnation Magnet assembly Magnet testing

Magnet Testing and Practical Applications

Magnetic Measurements Visit the Magnetic Measurement Laboratory Introduction to different measurement techniques Field mapping Rotating coil technique Stretched wire technique Practical work in magnetic measurement lab I8 Participants will measure magnets using rotating coil bench Analysis of mesurement results with CERN experts

Visit of Magnetic Measurement Laboratory

Field Mapping Fluxmeter Hall probe

Rotating Coil Measurements Tangential coil Radial flux Radial coil Tangential flux

Streched Wire Measurements

Looking forward... ...to welcome you at CERN!