Abstract:
A monitor for use in sample testing comprises a sample chamber for receiving a vessel containing a light-emitting substance, and an avalanche photodiode for receiving the emitted light and connected to a circuit for measuring the light received by the avalanche photodiode. The use of an avalanche photodiode enables the monitor to be portable and robust and to be included in a portable kit for carrying out hygiene monitoring in the field.
Abstract:
Cette invention concerne un module (2) d'acheminement optique adapté pour une utilisation dans un microscope à lumière (1) pour l'analyse d'échantillons simultanément avec une source (10) primaire de lumière et une source (7) secondaire de lumière, de longueurs d'ondes différentes. Le module (2) comprend un logement sur lequel sont montés des premier et second systèmes polariseurs de fractionnement des rayons PBS1, PBS2 le long d'une trajectoire de faisceau lumineux primaire à travers le module, et comportant des moyens (5, 6) d'entrée et de sortie de faisceau lumineux secondaire situés à l'opposé des différents systèmes polariseurs de fractionnement des rayons PBS1, PBS2, ayant une plage de longeur d'onde de fonctionnement prédéterminée définie entre des longueurs d'ondes transitionnelles de plan s et p, excluant sensiblement la bande de longueur d'onde de la source lumineuse primaire et de sorte qu'au moins un élément de plan polariseur de chacune de la source lumineuse secondaire et d'une sortie lumineuse secondaire provenant de l'échantillon est soumise à une transmission et une réflexion différentes de celles auxquelles la source lumineuse primaire est soumise au niveau de chacun des premier et second systèmes polariseurs de fractionnement des rayons PSB1, PSB2. Lesdits systèmes sont en outre formés et agencés pour définir une trajectoire de faisceau lumineux secondaire de l'entrée (5) à la sortie (6) de sorte que la trajectoire de faisceau lumineux secondaire soit sensiblement amenée en alignement avec une jambe située en dehors de la trajectoire dudit faisceau primaire en amont de l'échatillon, par ledit premier système polariseur de fractionnement des rayons PBS1, et est séparé en retour hors d'une jambe de retour de la trajectoire dudit faisceau lumineux primaire en aval de l'échantillon par ledit second système polariseur de fractionnement des rayons PBS2. Cet agencement permet lors de l'utilisation (2) dans un microscope à lumière (1), de contrôler la surface d'incidence d'un faisceau lumineux
Abstract:
The quenching circuit comprises a signal comparator (CP) having a first input connected to the photodiode (SPAD) under control and a second input connected to a balancing impedance (C) equal to that of the photodiode. At the output of the comparator (CP) there is connected a signal generator (M), which generates a quenching signal (S) having a predetermined duration each time there is an imbalance between the two inputs of the comparator. Circuital switching means (I1, I2, I3, I4) are provided, capable of holding the bias voltage of the photodiode normally high and of lowering it below the breakdown level following the generation and for the entire holding time of said quenching signal.
Abstract:
PROBLEM TO BE SOLVED: To solve a problem of a single photon detector, where a signal output by the detection of a single photon is often weak and, in some cases, it is difficult to discriminate it from another artifact output from the detector.SOLUTION: A photon detection system includes: a photon detector (APD 51) configured to detect single photons; a signal divider (a power distributor 55) to divide the output signal of the photon detector into a first part and a second part, where the first part is substantially identical to the second part; a delay means (a delay line 56) to delay the second part with respect to the first part; and a combiner (a hybrid coupler 61) to combine the first part and the delayed second part of the signal such that the delayed second part is used to cancel periodic variations in the first part of the output signal.
Abstract:
A avalanche diode arrangement comprises an avalanche diode (11) that is coupled to a first voltage terminal (14) and to a first node (15), a latch comparator (12) with a first input (16) coupled to the first node (15), a second input (17) for receiving a reference voltage (VREF) and an enable input (21) for receiving a comparator enable signal (CLK), and a quenching circuit (13) coupled to the first node (15).
Abstract:
An apparatus comprising: at least one single photon avalanche diode pixel configured to operate in a first mode to output a digital single photon detection event, the pixel comprising: a single photon avalanche diode; and at least one output transistor configured to provide an analogue output current from the single photon avalanche diode, such that the at least one single photon avalanche diode pixel is further configured to operate in a second mode to output the analogue output current indicating a level of illumination of the pixel.
Abstract:
An accurate and rapid method for characterizing the performance of an APD and setting its operating voltage Vop to an optimal value uses an on-board LED or other pulsed light source to measure APD responses at different operating voltages Vop. An estimated breakdown voltage Vb is determined by comparing the measured responses, and the Vop is adjusted to a new value at a fixed offset from the estimated Vb. The fixed offset is selected according to ambient light conditions, including the presence or absence of light background noise, and whether the sun is partially or fully in the field of view. The method is iterated until convergence, or until a maximum number of iterations is reached. In embodiments, a plurality of APD's having a common Vop can be adjusted, and the Vop is never set below a minimum value VopBW necessary to meet timing requirements for a missile guidance system.