US-12625074-B2 - Time measurement device, fluorescence lifetime measurement device, and time measurement method

Abstract

A time measurement apparatus 10 includes a TAC circuit 12 , a measurement gate 11 , a control unit 14 for setting a gate dead time, which is a time during which the measurement gate 11 is set to be in the second state, in the measurement gate 11 , and the control unit 14 for deriving and outputting time information related to the detection signal based on a measurement signal output from the TAC circuit 12 , and the control unit 14 functioning as a setting unit sets a time, which is an integral multiple of a repetition period of fluorescence detected by the detector 4 and is longer than a dead time of the TAC circuit 12 itself, in the measurement gate 11 as a gate dead time.

Inventors

• Fuminori NIIKURA

Assignees

• HAMAMATSU PHOTONICS K.K.

Dates

Publication Date

20260512

Application Date

20210513

Priority Date

20200806

Claims (8)

1. 1 . A fluorescence lifetime measurement apparatus that measures a lifetime of fluorescence emitted from a measurement target, the fluorescence lifetime measurement apparatus comprising: a light source configured to generate light; a detector configured to detect fluorescence with a repetition period from a measurement target irradiated with the light and output a detection signal; a time-amplitude converter configured to receive an input of the detection signal and output a measurement signal corresponding to a time associated with the detection signal; a gate configured to be provided between the detector and the time-amplitude converter and set to be in a first state where the detection signal is transmitted in a direction of the time-amplitude converter, or a second state where the detection signal is not transmitted in a direction of the time-amplitude converter; a controller configured to receive the measurement signal corresponding to the time associated with the detection signal when the gate is set to be in the first state, wherein the controller sets a gate dead time during which the gate is set to be in the second state in the gate, and derive and output time information related to the detection signal based on the measurement signal output from the time-amplitude converter, and the controller sets a time, which is an integral multiple of the repetition period of the fluorescence detected by the detector and is longer than a dead time of the time-amplitude converter itself, in the gate as the gate dead time; and a computer configured to derive a fluorescence lifetime of the measurement target based on the time information.
2. 2 . The fluorescence lifetime measurement apparatus according to claim 1 , further comprising: a delay generation circuit, wherein the controller sets a delay amount that is the integral multiple of the repetition period in the delay generation circuit, the delay generation circuit receives an input of the detection signal that has passed through the gate set to be in the first state, and outputs a delay signal delayed by the delay amount set by the controller with respect to the detection signal to the gate, and the gate is set to be in the first state to transmit the detection signal, is set to be in the second state until receiving an input of the delay signal, and receives the input of the delay signal, and then is set to be in the first state until a new detection signal is input.
3. 3 . The fluorescence lifetime measurement apparatus according to claim 1 , wherein the time-amplitude converter outputs the measurement signal corresponding to a time associated with the detection signal as an analog signal, and the fluorescence lifetime measurement apparatus further includes: a converter that converts the analog signal output from the time-amplitude converter into a digital signal and outputs the digital signal.
4. 4 . The fluorescence lifetime measurement apparatus according to claim 1 , further comprising: a counter configured to output a count signal in accordance with a clock signal, wherein the time-amplitude converter receives inputs of the detection signal and the clock signal and outputs the measurement signal corresponding to a time between the detection signal and the clock signal, and the controller derives and outputs the time information based on the count signal output from the counter and the measurement signal output from the time-amplitude converter.
5. 5 . The fluorescence lifetime measurement apparatus according to claim 1 , further comprising: a signal generator configured to generate a pulse signal for controlling output of light from the light source, wherein the signal generator outputs a setting signal indicating the repetition period of the fluorescence, which is synchronized with the pulse signal, to the controller.
6. 6 . The fluorescence lifetime measurement apparatus according to claim 1 , wherein the computer outputs a setting signal indicating the repetition period of the fluorescence to the controller.
7. 7 . The fluorescence lifetime measurement apparatus according to claim 1 , further comprising: a signal generator configured to generate a pulse signal for controlling output of light from the light source, wherein the generator outputs a synchronization signal synchronized with the pulse signal, the fluorescence lifetime measurement apparatus further includes a time measurement instrument that outputs a signal corresponding to the synchronization signal, and the controller derives the time information based on the signal corresponding to the synchronization signal.
8. 8 . A time measurement method executed by a time measurement apparatus, the time measurement method comprising: detecting, at a detector, fluorescence with a repetition period from a measurement target irradiated with light and outputting a detection signal; receiving, at a time-amplitude converter, an input of the detection signal and outputting a measurement signal corresponding to a time associated with the detection signal; receiving the measurement signal corresponding to the time associated with the detection signal when a gate is set to be in a first state, wherein a gate is configured to be provided between the detector and the time-amplitude converter and set to be in the first state where the detection signal is transmitted in a direction of the time-amplitude converter, or a second state where the detection signal is not transmitted in a direction of the time-amplitude converter; setting a gate dead time during which the gate is set to be in the second state; and deriving and outputting time information related to the detection signal based on the detection signal output from the time-amplitude converter, wherein the first dead time is longer than a second dead time of the time-amplitude converter itself.

Description

TECHNICAL FIELD One aspect of the present invention relates to a time measurement apparatus, a fluorescence lifetime measurement apparatus, and a time measurement method. BACKGROUND ART A time correlated single photon counting (TCSPC) apparatus that performs fluorescence lifetime measurement and the like is known (see, for example, Patent Literature 1). The TCSPC apparatus described in Patent Literature 1 includes a plurality of time-digital-converter (TDC) circuits. The TDC circuit outputs a time measurement result as a digital signal. CITATION LIST Patent Literature [Patent Literature 1] German Patent Application No. 102008004549 SUMMARY OF INVENTION Technical Problem In the TDC circuit described above and a TAC circuit that outputs a time measurement result as an analog signal, after a time is measured, a dead time in which a time cannot be measured again for a certain period of time is set. Due to the generation of the dead time, in a case where a phenomenon such as fluorescence is detected and time measurement related to the phenomenon (for example, fluorescence lifetime measurement) is performed, there is a concern that a time waveform for the phenomenon cannot be appropriately acquired. That is, since a time waveform cannot be acquired during a dead time, an accurate time waveform for the phenomenon may not be acquired even when time waveforms that could be obtained are synthesized. One aspect of the present invention has been made in view of the above circumstances, and relates to a time measurement apparatus, a fluorescence lifetime measurement apparatus, and a time measurement method which are capable of appropriately acquiring a time waveform related to a phenomenon. Solution to Problem A time measurement apparatus according to an aspect of the present invention includes a first time measurement instrument configured to receive an input of a detection signal, which is a phenomenon detected and output by a detector, and output a measurement signal corresponding to a time associated with the detection signal, a gate unit configured to be provided between the detector and the first time measurement instrument and set to be in a first state where the detection signal is transmitted in a direction of the first time measurement instrument, or a second state where the detection signal is not transmitted in a direction of the first time measurement instrument, a setting unit configured to set a gate dead time during which the gate unit is set to be in the second state in the gate unit, and a derivation unit configured to derive and output time information related to the detection signal based on the measurement signal output from the first time measurement instrument, in which the setting unit sets a time, which is an integral multiple of a repetition period of the phenomenon detected by the detector and is longer than a dead time of the first time measurement instrument itself, in the gate unit as the gate dead time. In the time measurement apparatus according to an aspect of the present invention, switching is made between a first state where a detection signal is input to the first time measurement instrument that outputs a measurement signal corresponding to a time associated with the detection signal and a second state where the detection signal is not input. A gate dead time that is an integral multiple of a repetition period of the phenomenon and is longer than a dead time of the first time measurement instrument itself is set in the gate unit, and the first time measurement instrument is set to be in the second state described above during the gate dead time. In such a time measurement apparatus, a gate dead time that is an integral multiple of the repetition period of the phenomenon is set in the gate unit, and thus a time waveform in time information derived based on the measurement signal output from the first time measurement instrument is equivalent to a waveform that is temporally continuous before and after the dead time (non-measurement state). Further, in the time measurement apparatus, since the gate dead time set in the gate unit is longer than the dead time of the first time measurement instrument itself, the dead time of the first time measurement instrument does not occur in spite of a measurement state where a detection signal is input to the first time measurement instrument, and thus it is possible to appropriately secure continuity of a time waveform before and after the gate dead time described above. As described above, according to the time measurement apparatus of the aspect of the present invention, it is possible to appropriately (continuously) acquire a time waveform related to a phenomenon. The time measurement apparatus may further include a delay generation circuit, in which the setting unit may set a delay amount that is an integral multiple of the repetition period in the delay generation circuit, the delay generation circuit may receive an input of the detection sig