An apparatus and method for improved S/N measurements useful for electron paramagnetic resonance imaging in situ and in vivo, using high-isolation transmit/receive surface coils and temporally spaced pulses of RF energy (e.g., in some embodiments, a RF pi pulse) having an amplitude sufficient to rotate the magnetization by 180 degrees followed after varied delays, by a second RF pulse having an amplitude half that of the initial pulse to rotate the magnetization by, e.g., 90 degrees (a pi/2 pulse), to the plane orthogonal to the static field where it evolves for a short time. Then a third RF pi pulse sufficient to rotate the magnetization by, e.g., 180 degrees, forms an echo (in some embodiments, the second and third pulses are from the same signal as the first pulse but are phase shifted by 0, 90, 180, or 270 degrees to reduce signal artifact), to image human body.

An apparatus and method for improved S/N measurements useful for electron paramagnetic resonance imaging in situ and in vivo, using high-isolation transmit/receive surface coils and temporally spaced pulses of RF energy (e.g., in some embodiments, a RF pi pulse) having an amplitude sufficient to rotate the magnetization by 180 degrees followed after varied delays, by a second RF pulse having an amplitude half that of the initial pulse to rotate the magnetization by, e.g., 90 degrees (a pi/2 pulse), to the plane orthogonal to the static field where it evolves for a short time. Then a third RF pi pulse sufficient to rotate the magnetization by, e.g., 180 degrees, forms an echo (in some embodiments, the second and third pulses are from the same signal as the first pulse but are phase shifted by 0, 90, 180, or 270 degrees to reduce signal artifact), to image human body.

A hydrogen gas sensor utilizing electrically isolated tunneling magnetoresistive sensing elements is provided. The hydrogen gas sensor comprises: a substrate in an X-Y plane, tunneling magnetoresistive sensors located on the substrate, and a hydrogen sensing layer located on the tunnel magnetoresistive sensors. The hydrogen sensing layer and the tunneling magnetoresistive sensor are electrically isolated from each other. The hydrogen sensing layer includes a multi-layer thin film structure formed from palladium layers and ferromagnetic layers, wherein the palladium layers are used for absorbing hydrogen in the air that causes a change in the orientation angle of a magnetic anisotropy field in each of the ferromagnetic layers in the X-Z plane into an X-axis direction. The tunnel magnetoresistive sensors are used for detecting a magnetic field signal of the hydrogen sensing layer, wherein the magnetic signal determines the hydrogen gas concentration. This hydrogen gas sensor ensures measurement safety.

Improved loop-gap resonators applicable to Electron-Spin Resonance spectroscopy and to quantum computing employ interdigitated capacitor structures to dramatically increase the capacitance of the resonator, along with corresponding decreases in loop size to enable measurements of small-volume samples or individual quantum bits (qubits). The interdigitated-capacitor structures are designed to minimize parasitic inductance.

Improved loop-gap resonators applicable to Electron-Spin Resonance spectroscopy and to quantum computing employ interdigitated capacitor structures to dramatically increase the capacitance of the resonator, along with corresponding decreases in loop size to enable measurements of small-volume samples or individual quantum bits (qubits). The interdigitated-capacitor structures are designed to minimize parasitic inductance.

Described herein are positron emission tomography (PET)-electron paramagnetic resonance imaging (EPRI) systems and methods of use. In one example, a PET-EPRI system includes a PET-EPR insert, a PET scanner including one or more solid-state photodetectors, and a subject module that can house a subject for scanning. The PET-EPR insert includes an EPR resonator that can nest inside the PET scanner. The EPR resonator includes a resonator that can receive the subject module, a shield encircling the resonator and one or more rapid scan coils (RS-coils) positioned around the shield. The shield can prevent electrical coupling between the RS-coils and the resonator while being transparent to annihilation photons and magnetic field scans.

Described herein are positron emission tomography (PET)-electron paramagnetic resonance imaging (EPRI) systems and methods of use. In one example, a PET-EPRI system includes a PET-EPR insert, a PET scanner including one or more solid-state photodetectors, and a subject module that can house a subject for scanning. The PET-EPR insert includes an EPR resonator that can nest inside the PET scanner. The EPR resonator includes a resonator that can receive the subject module, a shield encircling the resonator and one or more rapid scan coils (RS-coils) positioned around the shield. The shield can prevent electrical coupling between the RS-coils and the resonator while being transparent to annihilation photons and magnetic field scans.

A ferromagnetic resonance (FMR) measurement method is disclosed wherein a magnetic film or stack of layers is patterned into elongated structures having a length along a long axis. A magnetic field (H) is applied in two different orientations with respect to the long axis (in-plane parallel and perpendicular to the long axis) or one orientation may be perpendicular-to-plane. In another embodiment, H is applied parallel to a first set of elongated structures with a long axis in the x-axis direction, and perpendicular to a second set of elongated structures with a long axis in the y-axis direction. From the difference in measured resonance frequency (Δfr) (for a fixed magnetic field and sweeping through a range of frequencies) or the difference in measured resonance field (ΔHr) (for a fixed microwave frequency and sweeping through a range of magnetic field amplitudes), magnetic saturation Ms is determined using formulas of demagnetizing factors.

A ferromagnetic resonance (FMR) measurement method is disclosed wherein a magnetic film or stack of layers is patterned into elongated structures having a length along a long axis. A magnetic field (H) is applied in two different orientations with respect to the long axis (in-plane parallel and perpendicular to the long axis) or one orientation may be perpendicular-to-plane. In another embodiment, H is applied parallel to a first set of elongated structures with a long axis in the x-axis direction, and perpendicular to a second set of elongated structures with a long axis in the y-axis direction. From the difference in measured resonance frequency (Δfr) (for a fixed magnetic field and sweeping through a range of frequencies) or the difference in measured resonance field (ΔHr) (for a fixed microwave frequency and sweeping through a range of magnetic field amplitudes), magnetic saturation Ms is determined using formulas of demagnetizing factors.

A method of detecting spins in a sample, includes exciting the spins of the sample by means of a radio-frequency or microwave electromagnetic pulse for flipping the spins, and detecting a noise signal produced by the return of the spins to equilibrium by means of a device for counting radio-frequency or microwave photons.