A measuring assembly and method for layer thickness measurement of a layer applied to a substrate by means of a vapor deposition method includes a measuring head which is provided with at least one vibration plate, an extraction line which can be coupled in a gas-conducting or vapor-conducting manner with a first end having a vacuum chamber for the vapor deposition method and which can be coupled in a gas-conducting or vapor-conducting manner with an opposite second end having the measuring head, wherein the extraction line includes at least one heating section or at least one cooling section.