Abstract:
An atomic absorption spectrometer in which each sample is analyzed for all desired elements before starting the next sample. New features include the grating drive, lamp-carousel alignment, pulsed atom source, lamp-drift compensation, and dynamic range control. The grating (G) is driven by an arm (A), the arm (A) by a taut band (B) wound on a drum (D), and the drum (D) directly by a motor. The lamp carousel (C) mounts on an ''L''-shaped rocker with one horizontal and one vertical arm. The carousel (C) rotates on a horizontal axis (P1) at the end of the vertical arm. The rocker itself pivots on a horizontal axis (P2) at the corner of the L; it is driven about its axis by a motor (M2) and screw (W) at the other end of the L. Carousel (C) rotation on its axis moves the right lamp into position and adjusts it accurately in vertical direction. Pivoting of the rocker simultaneously on its corner axis positions the lamp accurately in the horizontal direction. The pulsed atom source is a combined angled-gas-jet- and discharge unit. During pulses it yields high absorption with better detectability limits; average power is lower. The lamp-drift compensator makes double duty of the absorber pulsation to obtain a lamp-intensity reading between pulses. Dynamic range control is obtained by even further exploiting the pulsation, namely by taking measurements at a known delay (and decay) time after each pulse.
Abstract:
A scanning densitometer is disclosed for obtaining color density measurements from colored samples, such as color bars and the like. The scanning densitometer includes a densitometer head (100) and a densitometer head transport system (101) having transport bars (102, 103). A sample sheet is positioned under the transport bars (102, 103) and the self-propelled head (100) moves over the sheet along the bars (102, 103) toward an end limit stop (105). During a return movement from the end limit stop (105) to a docking end housing (110), color measurement data is obtained. Upon docking at the docking end housing (110), an optical communications interface is provided so that data from the densitometer head (100) can be transmitted to a host computer.
Abstract:
A spectrophotometer of the type using a pulse motor (P) to rotate a diffraction grating (G) through a speed reducing mechanism (B) has a capability of constructing a conversion table according to a program, by which table a rotation amount of the motor (P) is converted to a corresponding wavelength of output light from a monochromator (MC). The spectrophotometer is capable of designating a calibration mode in which an emission peak at a known wavelength of light from a light source is detected, a coefficient in a conversion equation is determined on the basis of the known wavelength of the emission peak and a rotation amount of the motor (P) at a time when the emission peak is detected, and the determined coefficient is used to construct the conversion table which is then stored in a nonvolatile memory. In an analysis mode, a rotation amount of the motor (P) is converted to a corresponding wavelength in accordance with the conversion table in the nonvolatile memory.
Abstract:
L'appareil de positionnement décrit sert à positionner avec précision une pièce d'un dispositif par rapport à une autre et est destiné à être compatible avec des espaces sous-vide, de façon à pouvoir être utilisé dans des chambres sous ultravide. A cet effet, aucune lubrification n'est permise sur les pièces en mouvement les unes par rapport aux autres, de sorte que tous les contacts coulissants au niveau des surfaces en mouvement les unes par rapport aux autres doivent être évitées. Le mode de réalisation préféré est destiné à être utilisé pour faire tourner un réseau de diffraction à l'intérieur d'une source lumineuse monochromatique du type Cerny, Turner sous ultravide. Un organe de translation piézoélectrique linéaire de type INCHWORM (60) est utilisé à l'intérieur de la chambre à vide pour effectuer l'entraînement d'un élément de sortie (64) en paliers croissant à très petits pas avec une très grande précision. Une bande (61) est utilisée pour transformer le mouvement linéaire de l'élément de sortie en mouvement rotatif du support (53) du réseau de diffraction, ce qui est obtenu par enroulement de la bande autour d'un support cylindrique (58) du réseau de diffraction et par fixation des deux extrémités de la bande par l'intermédiaire d'un dispositif de tension (65) à l'élément de sortie (64), produisant ainsi une transmission du mouvement sans dérapage. Un pivot flexible (48, 49) est utilisé pour soutenir le support cylindrique à partir d'une structure fixe, de façon à permettre la rotation du support sans glissement ou sans jeu. Un détecteur, constitué par exemple par un lecteur à échelle optoélectronique (74), lit la position du support rotatif directement à d'une échelle de bande (73) enroulée autour dudit support, de façon à fournir une indication sur le mouvement du réseau.
Abstract:
A system for rapid-scan spectral analysis comprising a concave holographic diffraction grating (18) continuously rotated at a substantially constant angular velocity to provide a rapid scanning monochromator (a monochromator is used to transfer nominal regions of wavelengths out of the continuous light source). The unique sampling circuitry uses an optical shaft encoder (42). The angular velocity and angular acceleration of the grating (18) are calculated from time measurements, just before the first wavelength of interest falls on the detector. This information is used to control the Analog to Digital converter sampling rate across the region of interest. The samples as a function of time are stored in a memory buffer (58) so that each data point corresponds to a wavelength.
Abstract:
A system comprising: a light pipe that includes a variable length portion; a sample tube configured to contain a sample and to be inserted into an opening of the light pipe; and a cap configured to be inserted into the sample tube and to cause reflection of light toward a spectrometer.
Abstract:
A Micro-Electro-Mechanical System (MEMS) apparatus provides for self- calibration of mirror positioning of a moveable mirror of an interferometer. At least one mirror in the MEMS apparatus includes a non-planar surface. The moveable mirror is coupled to a MEMS actuator having a variable capacitance. The MEMS apparatus includes a capacitive sensing circuit for determining the capacitance of the MEMS actuator at multiple reference positions of the moveable mirror corresponding to a center burst and one or more secondary bursts of an interferogram produced by the interferometer based on the non-planar surface. A calibration module uses the actuator capacitances at the reference positions to compensate for any drift in the capacitive sensing circuit.