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Oriel Merlin™ Digital Lock-in Radiometry System

Oriel Merlin™ Digital Lock-in Radiometry System
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Oriel Merlin™ Digital Lock-in Radiometry System - 1

1222 Phone: 1-800-222-6440 • Fax: 1-949-253-1680 S p e c t r o s c o p y I n s t r u m e n t s MONOCHROMATORS AND SPECTROGRAPHS BENCHTOP SPECTROMETERS MINISPECTROMETERS SINGLE CHANNEL DETECTION SYSTEMS AND CCD CAMERAS ACCESSORIES FOR FT-IR SPECTROMETERS SPECTROSCOPY INSTRUMENTS Oriel Merlin™ Digital Lock-in Radiometry System 70100 Merlin™ Control Unit Measure UV to IR optical radiation with the Merlin™ Digital Lock-in Radiometry System and its family of calibrated detectors. The unique Smart Ranging™ feature gives you seamless gain switching. Over seven decades of input signal values, sub-microvolts to volts, are easily accommodated without electrical transients. We offer single and dual channel RS-232 and GPIB-488 Merlin instruments; each channel includes a reference capability. A broad selection of calibrated detectors, which have preamplifiers matched to Merlin, are available (see page 1224 to page 1231). Merlin™ works with chopped radiation, repetition rates from 8 to 1100 Hz. An external chopper wheel is required; Merlin provides power and control for the chopper. What makes up a Merlin Digital Lock-in System? Typically three components make up a Merlin System: • Merlin Control Unit • Detector(s) with preamplifier • Optical Chopper These three components were designed to work together as a system. When you plug the detector into the Merlin Control Unit, Merlin identifies the detector and, if you are using a calibrated detector(s), downloads the calibration information. Merlin Control Unit Merlin is a true digital lock-in. A powerful signal processing computer performs the demodulation and filtering. This allows greater flexibility and fidelity than available from analog lock-ins. Select single or dual phase operation and single or double time constant (one of two pole filtering), as needed. The impressive computational capability allows immediate signal ratioing and conversion, and forms the basis for Smart Ranging™. The Merlin Control Unit is the heart of a Merlin Radiometry System. The Control Unit drives the chopper and acts as a lockin amplifier to retrieve the signal and reject unmodulated background radiation. It then computes the signal value using previously loaded calibration data. The signal value is displayed in selected units. We offer single channel and dual channel Merlins. The dual channel models support two detectors, but only one operates at a time. Optical Chopper The chopper modulates the radiation to be measured. We offer an open and two enclosed versions, with a selection of chopper blades. You don't need a separate chopper controller (or power source); it's built into the Merlin Control Unit. Use the sync input if your signal is modulated by other means. Your choice of chopper wheel (not included with any of the Chopper Heads) depends upon your desired chopping frequency. The 75154 Open Chopper is the most economical choice if you don’t require an enclosed beam path. The 75151 and 75152 are both enclosed chopper heads. Choose the 75151 if you are going to flange mount the chopper to other Oriel instruments; choose the 75152 if you are rod mounting the chopper head or hard mounting to an optical table. Merlin calculates the 1st harmonic content of the chopped signal and this provides the RMS value. Relation of this RMS value to the peak-to peak value of the signal varies depending on the ratio of the beam size to the chopper wheel aperture size. For a very small beam, i.e. a HeNe laser beam passing through a 5 aperture wheel, the signal is almost a square wave, and the resulting ratio of the measured RMS voltage to peak-topeak voltage is 0.4502. When the enclosed chopper wheel is illuminated by a totally uniform beam, a triangular wave shape results, and the resulting RMS is 0.3113 of the peak-to-peak value. Other illumination conditions produce intermediate values of the RMS factor. When you order a calibrated Merlin detector, you will receive data based on the square wave, small beam, experiment set-up. If your measurement conditions are different, you will need to modify the calibration factor to reflect the change in RMS multiplier.

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Oriel Merlin™ Digital Lock-in Radiometry System - 2

S p e c t r o s c o p y I n s t r u m e n t s 1223 Email: sales@newport.com • Web: newport.com MONOCHROMATORS AND SPECTROGRAPHS SINGLE CHANNEL DETECTION SYSTEMS MINISPECTROMETERS BENCHTOP SPECTROMETERS AND CCD CAMERAS FT-IR SPECTROMETERS ACCESSORIES FOR SPECTROSCOPY INSTRUMENTS Detector We offer the following detectors; please refer to the individual pages for complete details. Table 1 Detectors for Merlin™ Detector Type Usable Wavelength Range Reference Page Photomultipliers 160 to 1100 nm see page 1224 Silicon 185 to 1100 nm see page 1225 InGaAs 800 to 1700 nm see page 1227 Ge 700 to 1800...

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