Although, cryogenic Hall probes have been constructed to be as rugged and strain-free as possible for maximum reliability after repeated temperature cycling, they are precision semiconductor devices and must be treated accordingly. Do not touch the electrical system of the un-packaged Hall probe.

 

It is very important to understand that environmental stress from incompliant thermal expansions or mechanical sources can affect the output of the Hall probe and significantly modify the calibration curve.

 

When gluing the packaged Hall probe to a holder, match the thermal expansion coefficient of the glue as closely as possible to the expansion rate of 2.5 to 6.5x10-5 K-1. Highly filled non-conductive epoxies fit well into this category. Do not use cyanoacrylate adhesives because of high rate of shrinkage and biodegradable inclination. When gluing the un-packaged Hall probe, choose a material with thermal expansion coefficient in the range of 0.5 to 1.5x10-5 K-1 (ceramic, steel, glass). Use very tiny dot sizes to glue the sensor to the surface. In situations where the Hall probe must be glued on a material with higher coefficient of thermal expansion a buffer aluminum oxide substrate is recommended. The electrical system of the un-packaged types cannot be covered with adhesives nor with vacuum grease or other varnishes.

 

Mounting of the Hall probe's leads is necessary part of the probe gluing. Leads should not be formed closer to the package than 3 mm. Avoid reciprocal bending or tension on the leads. There is no allowable force trying to pull leads from the package during the thermal dilatation.

 

A lot of magnetic field measurements are made as close as possible to a sample surface. After the Hall probe mounting must be carefully examined the position and thermal elongation of all system elements to avoid unexpected clash with the sensing area.