A novel interferometric dilatometer in the 4-300 K temperature range: thermal expansion coefficient of SRM-731 borosilicate glass and stainless steel-304

We present a newly designed heterodyne interferometric dilatometer for the measurement of the coefficient of thermal expansion of solids in the 4-300 K temperature range. The instrument can measure non-monotonic thermal expansion curves and has an accuracy better than 200 nm across the whole 4-300 K measurement range. The compensation for the misalignment of the interferometer design and the configuration of the sample holder make the instrument suitable to carry out measurements on any kind of sample that can be produced in a bar or rod shape. The measurement of a standard SRM-731 borosilicate glass and an SS-304 sample are presented and compared with literature data.