The use of equivalent thickness multipliers permits the use of the standards magazine when standardizing the gauge for alloys of the base material.  The sequence for determining these multipliers can be run in one of two modes - single sample or double sample:

Single Sample Mode

• The gauge is standardized on its internal standards at a nominal thickness of, say, .250".

• After standardizing, the standards go out and the shutter closes.

• Manually install a .250" thick sample of the new alloy over the x-ray port and open the shutter.

• The gauge will read the difference between our internal standards and the sample.

• This data is stored as the multiplier for this alloy over the entire range of the gauge.

• This value is saved as an alloy identifier, for instance #172.

     Now in operation, the operator will "dial in" the nominal thickness of, say, .080" and the alloy identification, say, #172.  When he initiates auto standardize on the touchscreen, the gauge will zero itself on the alloy equivalent thickness as determined by the product of the nominal thickness times the alloy equivalent multiplier.

Double Sample Mode

• The gauge is standardized on its internal standards at a nominal thickness of, say, .050".

• After standardizing, the standards go out and the shutter closes.

• Manually install a .050" thick sample of the new alloy over the x-ray port and open the shutter.

• The gauge will read the difference between our internal standards and the sample.

• This data is stored as part of the multiplier.

• Repeat the above procedure at the high end of the gauge range, say, .600".

• This data is also stored.

• The two actual values are summed to give a multiplier increment for that alloy over the sampled range.

• This value is saved as an alloy identifier, for instance #182.

     Now in operation, the operator will "dial in" the nominal thickness of, say, .450" and the alloy identification, say, #182.  When he initiates auto standardize on the touch screen, the gauge will zero itself on the alloy equivalent thickness as determined by the product of the nominal thickness times the alloy equivalent multiplier.

     A significant feature of this dual sample approach to alloy compensation is that it accommodates alloy x-ray absorption changes as the required operational x-ray wavelength (kV) changes.

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