Abstract: A metrology tool for determining a parameter of interest of a structure fabricated on a substrate, the metrology tool comprising: an illumination optical system for illuminating the structure with illumination radiation under a non-zero angle of incidence; a detection optical system comprising a detection optical sensor and at least one lens for capturing a portion of illumination radiation scattered by the structure and transmitting the captured radiation towards the detection optical sensor, wherein the illumination optical system and the detection optical system do not share an optical element.

Abstract: The invention relates to a RF reception antenna device (10) for receiving MR signals in a MR imaging system. The device (10) comprises a RF resonant circuit including a RF reception antenna (15) for picking up the MR signals, and a RF amplifier (17) connected at its input to the RF resonant circuit for amplifying the picked up MR signals. The invention proposes to make provision for a detection circuit (18) configured to derive a switching signal from an output signal of the RF amplifier (17). A switching circuit (19) is responsive to the switching signal, wherein the switching circuit (19) is configured to switch the RF resonant circuit between a resonant mode and a non-resonant (i.e. detuned) mode.

Abstract: The invention relates to a RF reception antenna device (10) for receiving MR signals in a MR imaging system. The device (10) comprises a RF resonant circuit including a RF reception antenna (15) for picking up the MR signals, and a RF amplifier (17) connected at its input to the RF resonant circuit for amplifying the picked up MR signals. The invention proposes to make provision for a detection circuit (18) configured to derive a switching signal from an output signal of the RF amplifier (17). A switching circuit (19) is responsive to the switching signal, wherein the switching circuit (19) is configured to switch the RF resonant circuit between a resonant mode and a non-resonant (i.e. detuned) mode.

Abstract: Dynamic adjustment of the receiver gain during an MRI scan. To account for magnitude and/or phase distortions introduced by the receiver that are not necessarily identical at various receiver gains, a reference rf signal is applied to the receive chain by an additional antenna. Preferably the reference signal is adjusted such that its frequency lies at the border of the frequency band detected by the MR scan. Comparing the a priori known amplitude and phase of the reference signal with the amplitude and phase of the received reference signal allows to determine the distortions introduced at the respective receiver gain which are subsequently corrected. In a further embodiment, the reference signal is used to synchronize the modulation and demodulation units of a wireless transceiver system.