temperature control in dc spark system ii
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Temperature Control in DC Spark System II. Anders Korsbäck. Context. Introducing sample temperature control into DC Spark System II makes several interesting measurements possible Direct effect of temperature on breakdown rate In-situ annealing of samples - PowerPoint PPT PresentationTRANSCRIPT
Temperature Control in DC Spark System II
Anders Korsbäck
Context
28.4.2014Anders Korsbäck 2
Introducing sample temperature control into DC Spark System II makes several
interesting measurements possible
Direct effect of temperature on breakdown rate
In-situ annealing of samples
Temperature control was originally attempted in 2011-2012 but abandoned
Lack of gap distance control to compensate for thermal expansion
Temperature controller was damaged and broken in lab mishap
Installation of liquid nitrogen line in lab was delayed
Time was running out for people, other things got priority
Controller has now been repaired and put together after many trials and even
more errors (thanks to Kyrre for helping out!)
Overview of controller
28.4.2014Anders Korsbäck 3
Sample heating is carried out by electron bombardment of a plate in thermal (but not electrical – our
modification) contact with sample
Filament is heated ohmically, thermally emitted electrons are accelerated by 650 V potential to hit heater
anode and deposit their kinetic energy into it
EBHC runs feedback control, using thermocouple reading as input signal and regulating the filament
voltage and current
Nominal temperature range -180 °C to +1000 °C (+1200 °C without cooling)