Hamamatsu-photonics K.k.

Waseda University

Michito Hirayanagi

Shunsuke Adachi

Shigeyuki Nakamura

Tsuyoshi Ohta

Hiroki Suzuki

Kenichi Sato

Shinji Ohsuka

Shigeki Nakase

Shogo Kamakura

Hiromichi Tozuka

Toru Nishiyama

Tetsuya Uchiyama

Takaaki Kawai

Jun Kataoka

A readout circuit for reading out an output current from a photoelectric conversion element which collectively outputs currents generated in a plurality of pixels, each of which includes an avalanche photodiode, includes a current mirror circuit configured to receive the output current and output first and second currents having magnitudes in proportion to the output current, a photon counting circuit configured to count the number of photons incident on the photoelectric conversion element on the basis of the first current, an integral circuit configured to integrate the second current to generate a voltage signal, and a signal processing unit configured to determine a magnitude of light incident on the photoelectric conversion element on the basis of a counting result output from the photon counting circuit and a magnitude of the voltage signal output from the integral circuit.

Readout circuit

A Compton camera includes a scattering detection unit, an absorption detection unit, a signal processing unit, a first shield unit, and a second shield unit. The scattering detection unit detects Compton scattering of incident radiation emitted from a radiation source. The absorption detection unit detects absorption of incident radiation that has undergone Compton scattering at the scattering detection unit. The signal processing unit obtains an image of the radiation source based on coincident detection events of Compton scattering of radiation at the scattering detection unit and absorption of radiation at the absorption detection unit. The first and second shield units are provided between the scattering detection unit and the absorption detection unit. The first shield unit selectively allows forward-scattered radiation to pass and selectively blocks back-scattered radiation.

Compton camera

A reverse bias voltage is applied to a photodiode array provided with a plurality of avalanche photodiodes operated in Geiger mode and with quenching resistors connected in series to the respective avalanche photodiodes. Electric current is measured with change of the reverse bias voltage applied, and the reverse bias voltage at an inflection point in change of electric current measured is determined as a reference voltage. A voltage obtained by adding a predetermined value to the determined reference voltage is determined as a recommended operating voltage.

Photodiode array, method for determining reference voltage, and method for determining recommended operating voltage

A driving system region which is a region where a light projector, a light receiver, and a signal processing circuit are installed together is disposed on one side of an optical system region comprising a light-projecting region and a light-receiving region, so that wires such as their mutual signal lines are kept from passing through the optical system region, whereby an omnidirectional distance detecting apparatus capable of complete 360-degree omnidirectional distance detection can be obtained. The influence of electric noise caused by the driving system of rotary mechanism and the like upon light-receiving signals and the like is suppressed, whereby the accuracy in distance detection can be improved.

Light-projecting/receiving unit and omnidirectional distance detecting apparatus

Growing community of inventors

Hamamatsu, Japan

Michito Hirayanagi