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Wire Quality. Jack Fowler. Wire Shipments. Receiving history Pre-series one - Confusion with specification. Wire was manufactured with thinner gold plating than specification. Pre-Series two and three - 50 km produced. Density 2.9 mg/ 200 mm, gold plating thickness .57 to .69 microns
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Wire Quality Jack Fowler
Wire Shipments • Receiving history • Pre-series one - Confusion with specification. Wire was manufactured with thinner gold plating than specification. • Pre-Series two and three - 50 km produced. Density 2.9 mg/ 200 mm, gold plating thickness .57 to .69 microns • Production series - 500 km produced. Density 2.9 mg/ 200 mm, gold plating thickness >.5 to .7 microns Fowler Duke HEP
Receiving Inspection • Pre Series 1 – Confirmed that wire was out of spec, looked at two samples under SEM • Pre Series 2 and 3 – Inspected 5 samples from 5 spools under SEM, sample sent to CERN • Production Series – Inspected wire from 10 spools from three different plating lots, sample sent to CERN Fowler Duke HEP
Surface Quality • Specification states “Gold plating must be smooth, uniform and free of defects: specifically holes of plating, poor adhesion, flaking, peeling, deep scratches, blisters etc are not acceptable.” • Scratches have been observed on all series of wire • Toshiba states that these occur due to the guide rollers and friction during the spooling process Fowler Duke HEP
Examples of Scratches Fowler Duke HEP
Gold Plating Process • Wire travels through 3 plating baths • The raw wire is acid etched and rinsed • Pre plated in solution of .1 to .6 gm of Au / litre • H2 gas, heated and rinsed • Plated in solution of 10 to 30 gm of Au / litre • H2 gas, heated and rinsed • Plated in solution of 20 to 40 gm of Au / litre • H2 gas, heated and rinsed • Final spool Fowler Duke HEP
Gold Fusion Examples Fowler Duke HEP
Manufacturer Comments • Toshiba states that this type of condition can not be avoided because the pulley and wire will always have contact and the gold surface is soft. Also that any vibration during spooling may cause this. Fowler Duke HEP
Manufacturer Comments • Toshiba states that this type of condition might be avoided or improved by changing the guide pin to the pulley during the plating process • There are no guarantees Fowler Duke HEP
Summary and Follow Up • All series of wire have exhibited surface defects • What defects are acceptable? • What are the consequences of using this defective wire? • If we re order wire, type of scratches and size must be specifically detailed. • Do we now inspect wire from every spool? • How can we insure that inspection of the first few meters of wire can “certify” the spool for production? Fowler Duke HEP