The calibration process
By definition, calibration is a comparison between measurements, one of a known magnitude or correctness, which is typically called a “gold standard”, and another measurement comparable to the first one.
In the calibration process, there are four critical aspects that need to be controlled precisely:
1 – Comparison
The first step in the calibration process is the comparison to a known and traceable standard. At Gentec-EO, we always do this using Gold and not a Silver calibration standards, unlike some of our competitors.
This extra carefulness in the comparison process comes from decades of experience in the laser measurement business.
2 – Gold standard
Gentec-EO’s gold laser power detector heads are compared to NIST standard calorimeters at different wavelengths, in accordance to the different lasers used to calibrate your own detector heads. The laser beam has a nominal diameter appropriate for the detector, and is centered on the detector’s absorbing surface.
The laser energy impinging upon the test instrument is measured concurrently using a NIST standard calorimeter and a calibrated beam splitter. The beam splitter ratio is measured using NIST standard calorimeters. Before the measurements are performed, the test instrument is allowed to reach equilibrium with the laboratory environment.
The calibration factor is found by dividing the instrument output reading by the calculated average incident laser power. The calculation is based on the output reading of the NIST standard calorimeters
3 – Uncertainty calculation
At Gentec-EO we offer the best uncertainty on the market, which means more than just giving the customer the lowest uncertainty value. These calculations also need to follow recognized statistical calculation standards, including those given in NIST’s Technical Note 1297.
Another important parameter to verify, and one that is less known, is the confidence level. At Gentec-EO, we use a very high confidence level of 95%. Like every other step in the calibration process, our uncertainty calculations are done rigorously.
We don’t aim to give you just the lowest number, whatever its meaning, we rather aim to give your the true value, with the highest confidence possible.
4 – Certification
Gentec-EO has been using its own control quality system for many years and is now accredited ISO 9001:2015.
Over and above the quality system certification process, the most important aspect is how rigorously the different steps and parameters are controlled in order to deliver an accurate calibration day after day.