Minutes from target meeting held August 22 2008 in 892-1-B09

These minutes are available also from:

http://wwwcompass.cern.ch/compass/detector/target/Minutes/2008/

a) Yuri: cable dielectric protons could contribute to the measured background
signal. Teflon as target cell construction material would absorb microwaves.
SMC NMR coils were covered with Teflon tubing and were embedded into ammonia 
material. This resulted in background proton contribution about 7 %. A target 
cell from metallic mesh would be a proton free alternative to the plastic
cells. COMPASS TE proton signal-to-noise ratio is better than in the SMC.

b) Jaakko: the background proton NMR signals are in the same magnetic 
field like ammonia protons (small offset from central axis field possible). 
So these protons should be in the 0.9 mm coaxial cable inside the mixing 
chamber. The linewidth for background protons is different from ammonia 
protons. Thus fitting two gaussians with different second moments could help 
to distinguish the background signal from ammonia signal. 

c) Some highlights and recent developments from LT25: 

100 years anniversary of helium liquefaction by Kamerlingh Onnes 
http://en.wikipedia.org/wiki/Kamerlingh_Onnes

Public lecture from Philippe Lebrun (AT): Quantum fluids at work: 
superconductivity and superfluid at the Large Hadron Collider

Evening session on the World Helium Supply and Technological Solutions.

Industrial pulse tube refrigerators are now commonly used to re-liquefy 
evaporated helium in-situ (typically 10 l/d) and new cryogen free dilution 
cryostats are available. 
http://en.wikipedia.org/wiki/Pulse_tube_refrigerator
http://en.wikipedia.org/wiki/Dry_dilution_refrigerator

Talks on supersolids
http://en.wikipedia.org/wiki/Supersolid

New high Tc superconductors based on oxypnictides
http://en.wikipedia.org/wiki/Oxypnictide
http://en.wikipedia.org/wiki/High_temperature_superconductors