Indentation head for an indentation instrument

Indentation head system for an indentation instrument, comprising:

• an indenter tip adapted to be brought into contact with a surface of a sample along at least an indentation axis;
• a reference element arranged to support said indenter tip;
• wherein said indentation head system further comprises:
• a zero-level sensor arranged to output a signal indicating whether said indenter tip is displaced with respect to said reference element from a neutral relative position, considered along said indentation axis;
• an elastic element connected between said indenter tip and an actuator with known elongation, said actuator being connected to said reference element;
• a controller adapted to receive signals from said zero-level sensor to carry out servo control of said actuator based on output of said zero-level sensor and said known elongation of said actuator such that said zero-level sensor outputs a signal corresponding to a substantially zero displacement of said indenter tip from said neutral relative position, said controller furthermore being adapted to calculate a force applied by said indenter tip to said sample on the basis of an output of said known elongation of said actuator and an elastic coefficient of said elastic element.