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POP

POP. Danny Zhuang. FEEDBACK LOOP TO INPUT TO FIBER STRETCHER. RECORDS DM BUBBLE POPS. PXI-6133. RECORDS IF PHASE. PXI-6221. PXI-6221. AMPLIFIER. FIBER STRETCHER. DISPLACES TO FIX THE PHASE DIFFERENCE BETWEEN THE TWO BEAMS. LASER. PHOTODIODE. CONVERTS LIGHT INTO VOLTAGE. SPLIT.

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POP

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  1. POP Danny Zhuang

  2. FEEDBACK LOOP TO INPUT TO FIBER STRETCHER RECORDS DM BUBBLE POPS PXI-6133 RECORDS IF PHASE PXI-6221 PXI-6221 AMPLIFIER FIBER STRETCHER DISPLACES TO FIX THE PHASE DIFFERENCE BETWEEN THE TWO BEAMS LASER PHOTODIODE CONVERTS LIGHT INTO VOLTAGE SPLIT RECOMBINE INTERFERED BEAMS SENSOR SENSES DARK MATTER BUBBLE POPS

  3. Life with LabView • Text Based Programmer • Week and a half learning • Began coding, learned as I went • ActiveX controls, DAQmx Functions • LabView source is very messy (spaghetti code) • Powerful GUI’s • Excellent debugger

  4. COUPP • COUPP (Chicagoland Observatory for Underground Particle Physics) • 60 kg bubble chamber underground to avoid cosmic rays • Works to detect Dark Matter; can detect Gamma rays, neutrinos, muons, alpha, WIMPs, etc • CF3I(Trifluoroiodomethane) sensitive to both spin-dependent and spin-independent WIMP interactions • Ideal temperature for each particle detection 60°C 40°C 40°C Muon Neutron(s) WIMP

  5. SNOLAB • Underground physics Laboratory in Ontario, Canada (2km) • Specializes in neutrino and DM physics • Located in Vale Creighton Mine (Active Mine) S- Sudbury N- Neutrino O- Observatory

  6. The Job • Highly sensitive microphone • Neutron vs. WIMP • Neutron single scatter sounds exactly like WIMP • Multiple neutron scatter is distinguishable • Acoustic signature differentiates • Dark Matter nucleation has a much higher acoustic sound

  7. WIMP’s • Weakly Interactive Massive Particles • Could comprise of most if not all DM in the universe • React with weak force and gravity, no electromagnetism, difficult to see, no strong force so do not react well with atomic nuclei • Shares properties with neutrinos except large mass thus slower and cold

  8. Dark Matter • Matter inferred to exist because of gravitational effects on visible matter • Neither emits nor scatters light or other EM radiation • Would account for discrepancies between calculations of the mass of galaxies

  9. So Why… • What we know about the world makes up only 4% of the universe • The other 96% is divided into two parts, Dark Energy and Dark Matter

  10. The Old Bubble Chamber • Charged Magnetic field • Particle Detector • Particles influenced by magnetic field

  11. COUPP’s Bubble Chambers • Revived technology of particle physics • Used to detect WIMPs • Filled with superheated fluid (CF3I) • Depositing a small amount of energy can nucleate the formation of an easily visible bubble • Effectively blind to the largest category of backgrounds • Progress in rejecting alpha recoils by using acoustic signature of bubble formation

  12. When DM Passes • Note: WIMP’s rarely interact with ordinary matter • DM particle passes through bubble chamber • Collides with a nuclei • Elastic scatter, energy released • Triggers evaporation of small amount of CF3I • Resulting bubble grows • Digital cameras catch the process once bubble reaches 1 mm in size • Data stored for analysis • However, the previous acoustic sensors were giving off background radiation themselves, turned towards interferometry

  13. Interferometry • Family of techniques in which electromagnetic waves are superimposed (place over) in order to extract information about the waves • Used in the fields of astronomy, fiber optics, engineering metrology, optical metrology, oceanography, seismology, quantum mechanics, nuclear/particle physics, plasma physics, remote sensing, and bimolecular interactions

  14. Interferometers • Single beam is split them combined, halves travel different routes • Amplitude Splitting- primary wave is divided into two segments which travel different paths before recombining • Separate waves are combined to show some meaningful property that is diagnostic of the original state of the waves (superposition) • Routes cause a phase difference between the initially identical waves because of the unequal distances traveled by each beam • Quality of the interferometer depends on the positions of the mirrors being precisely stable

  15. Interferometers cont’d • 2 waves of same frequency combine and result is determined by phase difference, decides constructive or destructive interference • 1 crest 1 trough  destructive interference (cancel) • 2 crests  constructive interference (add) • Resulting total light field’s amplitude is sum of amplitudes of superimposed beams • Interference fringe- bands caused by beams of light that are in phase or out of phase with one another

  16. The Interferometer’s Role • Interferometer- instrument used to measure waves through interference patterns • Closed Laser, laser travels through optical fibers, laser couplers • Fibers detect the characteristic acoustic sound of a DM bubble nucleation

  17. Interference • Two or more light beams superimposed • Spatial and temporal overlap of the two light fields • Coherence (fixed phase relationship between the electric field values at different locations or at different times) of the two light fields • Spatial coherence- a strong correlation (fixed phase relationship) between the electric fields at different locations across the beam profile, similar amplitudes • Temporal coherence means a strong correlation between the electric fields at one location but different times, tells how monochromatic a source is or how well it can interfere with itself

  18. Interferometers are ubiquitous VLA (Very Large Array)- 27 telescopes giving 351 independent baselines at once, radio array Astronomical Interferometry

  19. Mach-Zehnder Interferometer • Used to determine relative phase shift between two nearly parallel beams from a coherent light source • High coherence light from laser is split into reference and sensor arm then recombined • Photodetector measures combined light intensity

  20. fiber couplers Instead of beam splitters and fibers Instead of open source External influence (noise)

  21. Intro to Fiber Optics • Optical fiber- thin, flexible fiber that acts as a waveguide, transmitting light between the two ends of the fiber • Also used for illumination, wrapped in bundles • Immune to EM interference • light goes through with few hindrances compared to electrical cables (better) • Wavelength division multiplexing (WDM)- each fiber can carry many independent channels with light of different wavelengths • Multimode fibers- fibers that support many waves, efficient, cheaper • Single mode fibers- fibers that support a single wave, few hindrances • Good sensors for strain, temperature, pressure (DM sensor)

  22. Laser Basics • Laser emit amplified light (electromagnetic radiation) with high spatial and temporal coherence • At higher temperatures, more current is needed to get the same power • Cold = more power • Window between effective output current and breaching max operating current is slim • Diode- semiconductor with 2 terminals, flows one way

  23. Hardware: Building the Interferometer

  24. Wavelength stabilized single mode fiber coupled laser diode • 5mW of 1300nm (wavelength) -infrared • Low threshold current and high slope efficiency • Operating temperature range: -40ºC 50ºC • Built-in monitor photodiode, thermo-electric cooler, and thermistor

  25. LASER SPLIT

  26. Optiphase PZ1 • Fiber wound piezoelectric element (transfers electrical to mechanical) • Takes in voltage, displaces the optical fiber to get rid of phase differences between 2 beams • High-speed fiber stretcher

  27. Sensor • Optical Fibers • Picks up noise

  28. FIBER STRETCHER DISPLACES TO FIX THE PHASE DIFFERENCE BETWEEN THE TWO BEAMS LASER SPLIT RECOMBINE INTERFERED BEAMS SENSOR SENSES DARK MATTER BUBBLE POPS

  29. InGaAs Fixed Gain Detector • Used to convert light into voltage • 700-1800 nm (infrared) • 150 MHz BW • Amplified photodetector

  30. FIBER STRETCHER DISPLACES TO FIX THE PHASE DIFFERENCE BETWEEN THE TWO BEAMS LASER PHOTODIODE CONVERTS LIGHT INTO VOLTAGE SPLIT RECOMBINE INTERFERED BEAMS SENSOR SENSES DARK MATTER BUBBLE POPS

  31. T-Cube Laser Diode Controller

  32. T-Cube TEC Controller

  33. PXI-6221 • Capable of both Analog Input and Analog Output (ideal for the feedback loop to the Fiber Stretcher) • Slower than 6133 (250k samples per second) PXI-6133 • Only Capable of Analog Input • 10 times faster than 6221 (2.5M samples per second)

  34. RECORDS DM BUBBLE POPS PXI-6133 RECORDS IF PHASE PXI-6221 AMPLIFIER FIBER STRETCHER DISPLACES TO FIX THE PHASE DIFFERENCE BETWEEN THE TWO BEAMS LASER PHOTODIODE CONVERTS LIGHT INTO VOLTAGE SPLIT RECOMBINE INTERFERED BEAMS SENSOR SENSES DARK MATTER BUBBLE POPS

  35. PID Controller • Proportional-Integral-Derivative (PID) control is the most common control algorithm used in industry and has been universally accepted in industrial control • generic control loop feedback mechanism used in industrial control systems • Attempts to minimize error by adjusting process control inputs • PID feedback loop fixes the phase difference between the two beams and keeps the ideal fringe (light/dark; constructive/destructive) • PID Controls • P- Proportional (Kp) • I- Integral (Ki) • D- Derivative (Kd)

  36. The “Car” Analogy • A car’s cruise control is a PID Controller

  37. PID Theory • P Response- determines ratio of output response to error signal • controls the speed of the control system response • depends on error (set point – process variable) • can cause process variable to oscillate and system to become unstable • I Response- sums error over time (past error) • increases more as the error term increases • D Response- predicts future error • causes output to decrease if process variable is increasing rapidly • increases with rate of change • very sensitive to noise

  38. PID Equation • U(t) = controller output • MV(t)= manipulated variable • Kp= proportional gain, constant • Ki = Integral gain, constant • Kd = Derivative gain, constant • E = error (Set Point – Process Variable) • T = Time

  39. Terminology

  40. FEEDBACK LOOP TO INPUT TO FIBER STRETCHER RECORDS DM BUBBLE POPS PXI-6133 RECORDS IF PHASE PXI-6221 PXI-6221 AMPLIFIER FIBER STRETCHER DISPLACES TO FIX THE PHASE DIFFERENCE BETWEEN THE TWO BEAMS LASER PHOTODIODE CONVERTS LIGHT INTO VOLTAGE SPLIT RECOMBINE INTERFERED BEAMS SENSOR SENSES DARK MATTER BUBBLE POPS

  41. School • Applied science jumpstart to career and prepare for the real world • Principles and the laws of science are applicable to many things • Ability to do specialized and targeted research goes a long way

  42. Computer Programming Awareness • Growing industry • Useful in almost any job field • In high demand • Creativity • FUN

  43. To the Next Group of Victims and Scientists • VI readme for all programs • My deepest regrets • Advice document listing useful tutorials, articles, websites, etc. • My programs

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