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

2. 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

3. Overview of cryogenics at CERN 3 Cryogenic installations in Irrad zone

4. THERMOPHYSICAL PROPERTIES Fluid 4 HeN2N2 ArH2H2 O2O2 KrNeAirWater Boiling temperature (Tb) – 1.013 bar (K) 4.277.387.320.390.2119.827.178.8373 Latent heat (evaporation at Tb) – kJ/kg 21199.1163.2448213.1107.787.2205.22260 Ratio volume gas (273 K) /liquid 7096527957988086531356685----- Specific mass of liquid (at Tb) – kg/m3 125804140071114024131204874960 4 Demonstration: LN 2 properties: clear liquid, mist of moisture, Balloons Cryogenic Fluids

5. 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

6. 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.