Description of the Role of Shot Noise in Spectroscopic Absorption and Emission Measurements with Photodiode and Photomultiplier Tube Detectors: Information for an Instrumental Analysis Course

Optical accelerometers are popular in some applications because of their better immunity to electromagnetic interference, and they are often more sensitive than other accelerometer types. Optical fibers were employed in most previous generations, making micro-fabrication problematic. The optical accelerometers that are suitable for mass manufacture and previously mentioned in the literature have various problems and are only sensitive in one direction (1D). This study presents a novel optical accelerometer that provides 3D measurements while maintaining simple hybrid fabrication compatible with mass production. The operating concept is based on a power change method that allows for measurements without the need for complex digital signal processing (DSP). Springs hold the proof mass between a light-emitting diode and a quadrant photo-detector, allowing the proof mass to move along three axes. Depending on the magnitude and direction of the acceleration affecting the system, the proof mass moves by a certain amount in the corresponding axis, causing some quadrants of the quadrant detector to receive more light than other quadrants. This article covers the design, implementation, mechanical simulation, and optical modeling of the accelerometer. Several designs have been presented and compared. The best simulated mechanical sensitivity reaches 3.7 μm/G, while the calculated overall sensitivity and resolution of the chosen accelerometer is up to 156 μA/G and 56.2 μG, respectively.

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“…For the optical noise, it can be determined by the noise equivalent power (NEP) and shot noise [ 34 ] using the following two equations:

where

is the electron charge, I is the current and

is the sampling frequency or the frequency that is used to acquire data. Based on the Shannon–Nyquist theorem

equals the double of the maximum frequency of operation.…”

Section: Computational Resultsmentioning

confidence: 99%

Design and Modeling of Fiber-Free Optical MEMS Accelerometer Enabling 3D Measurements

2022

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“…20,21 In particular, such limitations are calculated when students build a new instrument. 20,22,23 It is important for students to not only understand the concept behind individual figures of merit, but to determine them on their own from data they generate. 21 …”

Section: ■ Results and Discussionmentioning

confidence: 99%

Integrating Elemental Analysis and Chromatography Techniques by Analyzing Metal Oxide and Organic UV Absorbers in Commercial Sunscreens

et al. 2016

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A series of undergraduate laboratory experiments that utilize reversed-phase HPLC separation, inductively coupled plasma spectroscopy (ICP), and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) are described for the analysis of commercial sunscreens. The active ingredients of many sunscreen brands include zinc or titanium oxide in addition to organic acids. Students determine the zinc content using ICP, and the chemical composition as well as particle sizes using SEM-EDS. The organic UV absorbers octocrylene and oxybenzone are quantified using HPLC. With the incorporation of these interesting characterization techniques in second or fourth-year chemistry courses, and by having students analyze sunscreen samples that are medically relevant in terms of health effects, students engage in timely research and at the same time gain exposure to a variety of instruments in the analysis of a familiar household product.

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“…The sum of a mutually independent zero‐mean Gaussian noise is still a zero‐mean Gaussian noise with variance equal to the sum of the variances of the independent Gaussian noises . Thus, spectroscopic noise can be modelled as the summation

N_{sim} ((), x_{i}) = e ((), x_{i}) \sqrt{{n_{italicph}}^{2} ((), x_{i}) + {n_{italicth}}^{2} + {n_{italicrd}}^{2}}

of shot noise n ph (also referred to as photon noise), thermal noise n th , and readout noise n rd . e ( x i ) is Gaussian noise having a standard deviation of one and mean of zero .…”

Section: Methodsmentioning

confidence: 99%

“…of shot noise n ph (also referred to as photon noise), thermal noise n th , and readout noise n rd . [35,37] e(x i ) is Gaussian noise having a standard deviation of one and mean of zero. [36,38] The shot noise…”

Section: Samplesmentioning

confidence: 99%

Vector casting for noise reduction

Gebrekidan

Knipfer

Braeuer

2020

J Raman Spectroscopy

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We report a new method for the reduction of noise from spectra. This method is based on casting vectors from one data point to the following data points of the noisy spectrum. The noise‐reduced spectrum is computed from the casted vectors within a margin that is identified by an envelope‐finder algorithm. We compared here the presented method with the Savitzky–Golay and the wavelet transform approaches for noise reduction using simulated Raman spectra of various signal‐to‐noise ratios between 1 and 25 dB and experimentally acquired Raman spectra. The method presented here performs well compared with the Savitzky–Golay and the wavelets‐based denoising method, especially at small signal‐to‐noise ratios and furthermore relies on a minimum of human input requirements.

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Description of the Role of Shot Noise in Spectroscopic Absorption and Emission Measurements with Photodiode and Photomultiplier Tube Detectors: Information for an Instrumental Analysis Course

Cited by 6 publications

References 6 publications

Design and Modeling of Fiber-Free Optical MEMS Accelerometer Enabling 3D Measurements

Design and Modeling of Fiber-Free Optical MEMS Accelerometer Enabling 3D Measurements

Integrating Elemental Analysis and Chromatography Techniques by Analyzing Metal Oxide and Organic UV Absorbers in Commercial Sunscreens

Vector casting for noise reduction

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