Effect of thermal radiation on the measurement of the sample holder temperature over the cryogenic range for various types of temperature sensor installations

0568614 - ÚPT 2023 CZ eng A - Abstrakt
Urban, Pavel - Hanzelka, Pavel - Králík, Tomáš - Srnka, Aleš
Effect of thermal radiation on the measurement of the sample holder temperature over the cryogenic range for various types of temperature sensor installations.
16th Multinational Congress on Microscopy, 16MCM, 04-09 September 2022, Brno, Czech Republic. Book of abstracts. Brno: Czechoslovak Microscopy Society, 2022 - (Krzyžánek, V.; Hrubanová, K.; Hozák, P.; Müllerová, I.; Šlouf, M.). s. 150-151. ISBN 978-80-11-02253-2.
[Multinational Congress on Microscopy /16./. 04.09.2022-09.09.2022, Brno]
Grant CEP: GA TA ČR TE01020233
Institucionální podpora: RVO:68081731
https://www.16mcm.cz/wp-content/uploads/2022/09/16MCM-abstract-book.pdf

We present how the thermal radiation (300 K) affects precision of temperature measurement of a sample holder (or sample) in an UHV SEM/SPM microscope working at the range down to 20 K for various ways of temperature sensor mounting. For reliable and precise temperature measurement at cryogenic temperatures, a correct installation of the temperature sensor including good thermal contact both of the sensor and its leads with measured object is essential. We tested a special copper casing designed by us - Prismatic Sensor Bed (PSB) - for installation of Lake Shore temperature sensors (Cernox and Si diodes) encapsulated in SD packages. The sensor is soldered in the bed of the casing using indium solder ensuring good thermal contact. The sensor leads are also thermally anchored to the casing but electrically insulated from it. We tested three ways of mounting of the sensors in PBS on a cooled plate imitating insufficient thermal anchoring of electrical wires to the plate and thermal shielding of the casing. In our test, we used CERNOX temperature sensors with declared uncertainty of 5 mK at 5 K. Comparative measurement was also performed with sensors in SD package mounted by the simplest possible way without using of PBS. We proved that our sensors casing PBS is suitable for intended application of temperature measurement of the sample holder (or directly of sample) in the UHV SEM/SPM microscope. In contrary, measurement precision by “unprotected” sensors proved to be absolutely unsuitable due to the high deviation of measured temperature from the correct value exceeding a required precision of about 1 K.
Trvalý link: https://hdl.handle.net/11104/0339884