Cryogenic Course Beamline for Schools Cryogenic Course Beamline for Schools Torsten Koettig TE-CRG-CI 1

Overview of cryogenics at CERN 2 Superconducting magnets of LHC accelerator Helium at different operating temperatures (thermal shields, beam screens, distribution and magnets,…) Main users - Accelerators

Overview of cryogenics at CERN 3 Cryogenic installations in Irrad zone

THERMOPHYSICAL PROPERTIES Fluid 4 HeN2N2 ArH2H2 O2O2 KrNeAirWater Boiling temperature (Tb) – bar (K) Latent heat (evaporation at Tb) – kJ/kg Ratio volume gas (273 K) /liquid Specific mass of liquid (at Tb) – kg/m Demonstration: LN 2 properties: clear liquid, mist of moisture, Balloons Cryogenic Fluids

General Safety Practices 5 Personal Protective Equipment (PPE) Safety glasses (or face shield) Cryogenic gloves =>loosely fitting Full length pants that extend over shoe tops Closed-toed shoes that are impermeable to liquids Warning signs Demonstration: Condensation of Oxygen, Gysir, Table tennis balls, Film box

Cryogenic hazardous events 6 PHYSIOLOGICAL – CONTACT BURNS/FROST BITE  Due to the low viscosity and surface tension of cryogens, it will flow through clothing much faster than water. Demonstration: Leidenfrost effect fingers, cold surfaces, gummy bears, fabric Contact burns: Similar to hot burns Frost bite => freezing of skin and body parts: Permanent damage and discoloration seconds Exposure time on the order of seconds, not minutes! Inhalation: Inhalation of cold vapour can cause damage to the lungs and may trigger an asthma attack.