NMR microprobe detectors and methodologies that provide enhanced signal sensitivity for low-volume sample detection and analysis are described. In one embodiment the microprobe detector is a flat wire detector with a strip conductor having a length and width and ratio greater than 5 with a substantially uniform surface positioned on a low loss substrate in contact with a sample holder having a generally thin wall or at least a thin portion near where the sample probing and analysis occur.

Described herein are a magnetic resonance probe and a NMR, MRI, or EPR apparatus including the same. The magnetic resonance probe includes a conductor electrically coupled to the resonator and configured to transmit and receive electromagnetic radiation to and from a sample, wherein the conductor includes one or more cascaded narrowed regions along its longitudinal dimension and a slot within one of the one or more cascaded narrowed regions; and an electrical circuit coupled to the conductor and the resonator.

Systems and methods for reducing variability in the output impedance of an integrated switch-mode power amplifier (PA) split the output impedance between passive resistor, which may be on-chip, and a MOSFET switch of the amplifier. The PA may have a single-ended configuration or a differential configuration having two single-ended structures operating with opposite phases. In one implementation, the size of the MOSFET switch is larger than that of the MOSFET switch implemented in a conventional PA, but the size is still acceptable to operate the PA at a desired frequency. In addition, a calibration approach may be utilized to ensure that the MOSFET switch has a controlled and calibrated ON resistance, thereby providing stable output power levels of the PA and ensuring consistency and repeatability in NMR measurements.

Various approaches of receiving signals in integrated circuitry include implementing a voltage-mode passive mixer for down-converting the frequency of the received signals, a baseband output buffer, and a transconductance amplifier coupled between the voltage-mode passive mixer and baseband output buffer for presenting a high-impedance load to the voltage-mode passive mixer and shielding the baseband output buffer from a high-frequency feedthrough.

Various approaches of receiving signals in integrated circuitry include implementing two successive stages of signal manipulation and employing an interface having an AC coupling network and buffer circuits for decoupling the output impedance and common-mode level of the first stage of signal manipulation from the input impedance and common-mode level of the second stage of signal manipulation without degrading the performance of either stage.

An approach for accurately setting a duty cycle of PA switching waveforms uses an all-digital PVT sensor circuit. In various embodiments, the all-digital PVT sensor circuit measures a pulse width of a periodic reference signal using digital delay line, and subsequently, implements an off-chip digital calculation to program the digital delay line to delay this periodic reference signal so that, when the delayed periodic reference signal is combined with the original (undelayed) reference via a logical AND operation, the resulting signal conforms to a desired duty cycle. In one implementation, the PA is a class-D PA, which may have a single-ended configuration or a differential configuration having two single-ended structures operating in opposite phases.

Various approaches of adjusting a gain of received signals in integrated circuitry include implementing an open-loop source-degenerated amplifier having a pair of input devices for amplifying the received signals; boosting an effective transconductance of the input devices (e.g., using a pair of super-g.sub.m feedback loops); and setting a bias current of devices in the open-loop source-degenerated amplifier (e.g., using a constant-g.sub.m bias circuit.)

In a general aspect, a sample holder has multiple sample containers. In some instances, the sample holder can be received into a resonator package in a primary magnetic field of a magnetic resonance system. The resonator package includes a resonator configured to interact with a sample in a sample region. The sample holder includes a first sample and a calibration sample. The position of the sample holder relative to the resonator is calibrated. After calibrating the position of the sample holder, the sample holder is translated to position the first sample in the sample region. Magnetic resonance data is acquired based on magnetic resonance signals generated by an interaction between the resonator and the first sample.

Technologies relating to a magnetic resonance spectrometer are disclosed. The magnetic resonance spectrometer may include a doped nanostructured crystal. By nanostructuring the surface of the crystal, the sensor-sample contact area of the crystal can be increased. As a result of the increased sensor-sample contact area, the output fluorescence signal emitted from the crystal is also increased, with corresponding reductions in measurement acquisition time and requisite sample volumes.

A device for analyzing substances in a sample on the basis of a measurement of nuclear magnetic resonances including a magnetic field device configured to generate a magnetic field. The device is configured such that, in order to detect magnetic resonances induced in the sample by the generation of the magnetic field, provision is made of at least one magnetic field sensor which comprises at least one sensitive component with diamond structures. The diamond structures have nitrogen vacancy centers.