Wire Quality

1
Wire Quality

Jack Fowler
2
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 gt.5 to .7
  microns

3
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

4
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

5
Examples of Scratches
6
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

7
Gold Fusion Examples
8
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.

9
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

10
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?