What makes for a good laser?

Why a Correctly Dosed Laser Shot Is Crucial in Laser Flash Analysis

Thermal conductivity and diffusivity are among the most important thermophysical parameters for describing the heat transfer properties of a material or a component. For an exact measurement of the thermal diffusivity, the laser flash technique is the most accepted method today. The core of a laser flash apparatus (LFA) is, of course, the laser – along with the detector for data acquisition. With this in mind, NETZSCH has released a new development focused around a tailor-made laser for LFA.

What actually makes for a good laser for LFA measurement?

To make a long story short, it is not just the laser’s energy. It is much more important to dose the laser precisely, correspondent to the sample. If the laser pulse that is shot is too strong, one risks changing the sample’s composition and thus its properties, or even worse, destroying the sample. Moreover, with a correctly dosed laser pulse, one avoids heating the sample and thus obtaining false values from the measurement.

For dosing a laser pulse, the NETZSCH motto is: As slight as possible, but as strong as necessary. This is exactly how the Fast Light Source operates, thus preventing any change in the sample or measurement conditions and, in turn, any false thermal conductivity or diffusivity values. Moreover, the FLS 701 offers an extended measuring range with its particularly short and particularly long pulse lengths of 0.1 to 1.5 ms.

The new NETZSCH laser, developed and manufactured in Germany, can be directly installed into the new power unit P8 and thus saves on space in the vicinity of the LFA 427. Additionally, serviceability has been greatly improved by virtue of the fact that NETZSCH can now offer maintenance first-hand. Further facilitating servicing and repair is the fact that, in the event of a claim, the FLS 701 can be easily returned thanks to its compactness. The new laser also does not require any water cooling, which makes maintenance easier and improves ease-of-use.

The LFA 427 features high accuracy and reproducibility, short measurement times, variable sample holders and defined environmental conditions over the entire application range of -120°C to 2800°C. It also features long-term stability, and with the new FLS 701, exhibits only very small fluctuations in the measurement results (specific heat capacity) over a series of 100 shots.