Phase-sensitive detection in the undergraduate lab using a low-cost microcontroller

Schultz, K. D.

doi:10.1119/1.4953341

Cited by 15 publications

(7 citation statements)

References 8 publications

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“…Nevertheless, the first test shows that the spin-rotator method is perfectly working and we will discuss its advantages over the 4-point method at the end of this section. Furthermore, the test also shows that a lock-in amplifier can be easily implemented and run on a microcontroller, similar in spirit to previous works 28,29 . The stability of the system can be tested in the same manner as the numerical model.…”

Section: Resultsmentioning

confidence: 67%

Polarisation in spin-echo experiments: Multi-point and lock-in measurements

Tamtögl

Davey

Ward

et al. 2018

Review of Scientific Instruments

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Spin-echo instruments are typically used to measure diffusive processes and the dynamics and motion in samples on ps and ns timescales. A key aspect of the spin-echo technique is to determine the polarisation of a particle beam. We present two methods for measuring the spin polarisation in spin-echo experiments. The current method in use is based on taking a number of discrete readings. The implementation of a new method involves continuously rotating the spin and measuring its polarisation after being scattered from the sample. A control system running on a microcontroller is used to perform the spin rotation and to calculate the polarisation of the scattered beam based on a lock-in amplifier. First experimental tests of the method on a helium spin-echo spectrometer, show that it is clearly working and that it has advantages over the discrete approach i.e. it can track changes of the beam properties throughout the experiment. Moreover, we show that real-time numerical simulations can perfectly describe a complex experiment and can be easily used to develop improved experimental methods prior to a first hardware implementation.

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Section: Resultsmentioning

confidence: 67%

Polarisation in spin-echo experiments: Multi-point and lock-in measurements

Tamtögl

Davey

Ward

et al. 2018

Review of Scientific Instruments

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“…A mathematical derivation and a simulation (Figure S5) showing how the AD630 modulator/demodulator combined with subsequent low pass filtering isolates the desired frequency response are provided in the Supporting Information. Our design extends a prior report of a 1-channel LIA with an in-phase (V x ) output component by constructing a two-channel LIA with an out-of-phase (V y ) output component as well. − The input voltage signal (V in ) to be analyzed by the LIA first goes through a high pass filter, which also removes any time independent (DC) component. The signal then goes to two modulator/demodulators for processing.…”

Section: Discussionmentioning

confidence: 99%

Low-Cost, High-Performance Lock-in Amplifier for Pedagogical and Practical Applications

Suganuma

Dhirani

2020

J. Chem. Educ.

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Lock-in amplifiers (LIAs) are commonly used in chemistry laboratories to improve noise-to-signal ratios. Constructing and testing a suitably designed LIA provide undergraduate students with an excellent opportunity to learn about theory, construction, and applications of LIA. In particular, students can learn about time-dependent behavior and various components, from resistors (R) and capacitors (C) to packaged microchips such as demodulators and phase shifters. We provide here design and performance characteristics of a two-(Vx, Vy) channel LIA based on balanced modulator/demodulators (AD630). The LIA includes configurable resistor−capacitor (RC) high-pass and low-pass filters, various op-amp circuits, and a phase-shifter. Various configurations of resistors/capacitors, as well as salt solutions and isopropanol/pentane mixtures, are used as samples to measure conductance or capacitance to test both V x and V y channels of the LIA. The results are consistent with behaviors expected theoretically. The LIAs yield excellent noise/signal ratios with peak-to-peak values that are <0.2% and that compare favorably with commercial LIA performance.

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“…One possible method is to fabricate a microcontroller-based lockin amplifier, as demonstrated in Ref. [12].…”

Section: Voltage Amplifiermentioning

confidence: 99%

Temperature-dependent transport measurements with Arduino

et al. 2018

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The current performances of single-board microcontrollers render them attractive not only for basic applications but also for more elaborate projects, amongst which are physics teaching or research. In this article, we show how temperature-dependent transport measurements can be performed using an Arduino board, from cryogenic temperatures up to room temperature or above.We focus on two of the main issues for this type of experiments: the determination of the sample temperature and the measurement of its resistance. We also detail two student-led experiments:evidencing the magnetocaloric effect in Gadolinium and measuring the resistive transition of a high critical temperature superconductor. 6 "Thermocouple amplifier," (). 7 "Platinum ntd sensor resistance to temperature conversion tables are available at the following websites," , .8 "Rtd-to-digital converter," https

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Phase-sensitive detection in the undergraduate lab using a low-cost microcontroller

Cited by 15 publications

References 8 publications

Polarisation in spin-echo experiments: Multi-point and lock-in measurements

Polarisation in spin-echo experiments: Multi-point and lock-in measurements

Low-Cost, High-Performance Lock-in Amplifier for Pedagogical and Practical Applications

Temperature-dependent transport measurements with Arduino

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