A cytometer includes an avalanche photodiode, a switching power supply, a filter, and voltage adjustment circuitry. The switching power supply includes a feedback loop. The filter is electrically connected between the switching power supply and the avalanche photodiode. The voltage adjustment circuitry adjusts a voltage on the feedback loop based at least in part on a voltage measured between the filter and the avalanche photodiode.

Certain embodiments described herein are directed to optical detector and optical systems. In some examples, the optical detector can include a plurality of dynodes, in which one or more of the dynodes are coupled to an electrometer. In other configurations, each dynode can be coupled to a respective electrometer. Methods using the optical detectors are also described.

A cytometer includes an avalanche photodiode, a switching power supply, a filter, and voltage adjustment circuitry. The switching power supply includes a feedback loop. The filter is electrically connected between the switching power supply and the avalanche photodiode. The voltage adjustment circuitry adjusts a voltage on the feedback loop based at least in part on a voltage measured between the filter and the avalanche photodiode.

An apparatus, including: a probe to interface with a surface of a tissue; a light source optically coupled to the probe, the light source directing light of at least 1000 nm into the tissue; a detector optically coupled to the probe, the detector to detect light based on scattering of light from the light source in the tissue, and the detector having a light sensitivity in a range of at least 1000 nm; a processor coupled to the detector, the processor to: receive a signal from the detector corresponding to the detected light from the light source, and determine a blood flow measurement from the region of interest using diffuse correlation spectroscopy based on the signal.

A fluorescence lifetime measurement apparatus according to an embodiment of the present invention includes an illumination light generation unit configured to generate illumination light, a fluorescence photon detection unit configured to collect a fluorescence signal of fluorescence photons generated by illuminating at least one or more samples including fluorescent molecules with the illumination light; and a measurement unit configured to compute a fluorescence lifetime by applying a least square method to a simulation function and a function of the fluorescence signal.

[Task] To provide an automatic analysis apparatus including a photomultiplier tube which controls a sensitivity of the photomultiplier tube without adjusting a high voltage value. [Solution] An automatic analysis apparatus according to the present invention includes a photomultiplier tube which detects light from a reaction vessel; a determination unit which determines an output signal of the photomultiplier tube in a case where the photomultiplier tube is irradiated with first light; and a control unit which irradiates the photomultiplier tube with second light to lower a sensitivity of the photomultiplier tube in accordance with a determination result by the determination unit.

Disclosed herein is a method comprising: emitting electrons from an electron ejector in response to an incident photon; driving the electrons through a hole toward a detector configured to collect the electrons and provide an output signal representative of the incident photon; driving the electrons away from sidewalls of the hole, using an electric field.

A cytometer includes an avalanche photodiode, a switching power supply, a filter, and voltage adjustment circuitry. The switching power supply includes a feedback loop. The filter is electrically connected between the switching power supply and the avalanche photodiode. The voltage adjustment circuitry adjusts a voltage on the feedback loop based at least in part on a voltage measured between the filter and the avalanche photodiode.

A light sheet microscope includes an objective, an illumination optical system, a first adjustor, a second adjustor and a controller. The illumination optical system irradiates sample with a light sheet from a direction that is different from an optical axis direction of the objective. The first adjustor adjusts a relative position between a light sheet plane on which the light sheet is formed and the objective in an optical axis direction of the objective. The second adjustor adjusts a relative position between the light sheet plane and the sample in an optical axis direction of the objective. The controller controls the first adjustor on the basis of light that is from the light sheet plane and that is detected via the objective when a relative position between the light sheet plane and the sample is changed by the second adjustor.

A fluorescence lifetime measurement apparatus according to an embodiment of the present invention includes an illumination light generation unit that generates illumination light, a fluorescence photon detection unit that collects fluorescence photons generated by illuminating a sample including fluorescent molecules with the illumination light, a conversion unit that converts the collected fluorescence photons into a first clock signal and converts illumination light that does not pass through the sample into a second clock signal, a first module that analyzes a fluorescence lifetime of the collected fluorescence photons from the conversion unit, a control unit that designates a range of interest (ROI) of the sample from the first module, and a second module that analyzes a fluorescence lifetime of fluorescence photons corresponding to the ROI.