High Precision Measurements Using High Frequency Signals

Generalized lock-in amplifiers use digital cavities with Q-factors as high as 5X10^8. In this letter, we show that generalized lock-in amplifiers can be used to analyze microwave (giga-hertz) signals with a precision of few tens of hertz. We propose that the physical changes in the medium of propagation can be measured precisely by the ultra-high precision measurement of the signal. We provide evidence to our proposition by verifying the Newton's law of cooling by measuring the effect of change in temperature on the phase and amplitude of the signals propagating through two calibrated cables. The technique could be used to precisely measure different physical properties of the propagation medium, for example length, resistance, etc. Real time implementation of the technique can open up new methodologies of in-situ virtual metrology in material design

All-passive pixel super-resolution of time-stretch imaging

Based on image encoding in a serial-temporal format, optical time-stretch imaging entails a stringent requirement of state-of-the- art fast data acquisition unit in order to preserve high image resolution at an ultrahigh frame rate --- hampering the widespread utilities of such technology. Here, we propose a pixel super-resolution (pixel-SR) technique tailored for time-stretch imaging that preserves pixel resolution at a relaxed sampling rate. It harnesses the subpixel shifts between image frames inherently introduced by asynchronous digital sampling of the continuous time-stretch imaging process. Precise pixel registration is thus accomplished without any active opto-mechanical subpixel-shift control or other additional hardware. Here, we present the experimental pixel-SR image reconstruction pipeline that restores high-resolution time-stretch images of microparticles and biological cells (phytoplankton) at a relaxed sampling rate (approx. 2--5 GSa/s) --- more than four times lower than the originally required readout rate (20 GSa/s) --- is thus effective for high-throughput label-free, morphology-based cellular classification down to single-cell precision. Upon integration with the high-throughput image processing technology, this pixel-SR time- stretch imaging technique represents a cost-effective and practical solution for large scale cell-based phenotypic screening in biomedical diagnosis and machine vision for quality control in manufacturing.Comment: 17 pages, 8 figure

A new compact neutron spectrometer

A new compact neutron spectrometer has been designed, developed and characterized. The detector is based on EJ299-33 plastic scintillator coupled to silicon photomultipliers, and a digital implementation of pulse shape discrimination is used to separate events associated with neutrons from those associated with gamma-rays. The spectrometer is suitable over the neutron energy range 1 – 100 MeV, and the development illustrated with measurements made using an Am-Be radioisotopic source, a D-T sealed tube neutron generator and quasi-monoenergetic neutron beams produced using the iThemba LABS cyclotron. A segmented variation of the spectrometer is capable of providing directional information through the comparison of count rates between scintillator cells

The Hawaii Muon Beamline.

M.S. Thesis. University of Hawaiʻi at Mānoa 2017

Components for Wide Bandwidth Signal Processing in Radio Astronomy

In radio astronomy wider observing bandwidths are constantly desired for the reasons of improved sensitivity and velocity coverage. As observing frequencies move steadily higher these needs become even more pressing. In order to process wider bandwidths, components that can perform at higher frequencies are required. The chief limiting component in the area of digital spectrometers and correlators is the digitiser. This is the component that samples and quantises the bandwidth of interest for further digital processing, and must function at a sample rate of at least twice the operating bandwidth. In this work a range of high speed digitiser integrated circuits (IC) are designed using an advanced InP HBT semiconductor process and their performance limits analysed. These digitiser ICs are shown to operate at up to 10 giga-samples/s, significantly faster than existing digitisers, and a complete digitiser system incorporating one of these is designed and tested that operates at up to 4 giga-samples/s, giving 2 GHz bandwidth coverage. The digitisers presented include a novel photonic I/O digitiser which contains an integrated photonic interface and is the first digitiser device reported with integrated photonic connectivity. In the complementary area of analogue correlators the limiting component is the device which performs the multiplication operation inherent in the correlation process. A 15 GHz analogue multiplier suitable for such systems is designed and tested and a full noise analysis of multipliers in analogue correlators presented. A further multiplier design in SiGe HBT technology is also presented which offers benefits in the area of low frequency noise. In the effort to process even wider bandwidths, applications of photonics to digitisers and multipliers are investigated. A new architecture for a wide bandwidth photonic multiplier is presented and its noise properties analysed, and the use of photonics to increase the sample rate of digitisers examined

Data Acquisition, Analysis and Simulations for the Fermilab Muon \u3ci\u3eg−2\u3c/i\u3e Experiment

The goal of the new Muon g-2 E989 experiment at Fermi National Accelerator Laboratory (FNAL) is a precise measurement of the muon anomalous magnetic moment, aμ ≡ (g-2)/2. The previous BNL experiment measured the anomaly aμ(BNL) with an uncertainty of 0.54 parts per million (ppm). The discrepancy between the current standard model calculation of the aμ(SM) and the previous measurement aμ(BNL) is over 3σ. The FNAL Muon g-2 experiment aims at increasing the precision to 140 parts per billion (ppb) to resolve the discrepancy between the theoretical calculation and the experiment result. The anomaly, aμ is determined experimentally by measuring two frequencies. The magnetic field of the storage ring is measured with NMR probes and given in terms of equivalent proton spin precession frequency ωp in a spherical water sample at 34.7 °C. The difference frequency ωa between the muon spin-precession frequency and the cyclotron frequency in the storage ring magnetic field is encoded in the energy of the positrons from the muon decay and is measured with 24 electromagnetic calorimeters. By calculating the ratio ωa/ωp and combining with known constants, we can extract the anomaly aμ. This dissertation describes my contribution to the experiment, focusing on the extraction of the frequency ωa. My work can be classified into three categories: 1. Fast Data Acquisition (DAQ) system development, 2. A frequency-domain filtering approach to the analysis of the energy-integrated ωa data, 3. A GPU-based Monte Carlo of the frequency-domain filtering approach. The GPS timestamps readout, the DAQ health monitor and GPS data quality monitor page are presented in the Chapter 3. The FFT-based digital filtering analysis is presented in the Chapter 4. The GPU-based Monte Carlo simulation is presented in Chapter 5. The analysis work in the dissertation is based on the Run-1 data which is collected from March 2018 to July 2018