David Prutchi – Page 4 – diy Physics Blog

Excelitas Technologies (Perkin-Elmer) C30902SH Single-Photon Avalanche Photodiode (SPAD) used in d.i.y. SPCM

Posted on January 25, 2012 by David Prutchi Posted in Bell's Inequality Test, Chapter 8 - Entanglement, Entanglement, Quantum Random Number Generation, Single-Photon Counting Modules (SPCMs), Single-Photon Experiments

Excelitas Technologies C30902S-DTC SPAD used in d.i.y. single-photon counting module

Image Credit: Excelitas Technologies

Figure 144 in the book shows the schematic diagram for our d.i.y. passively-quenched SPCM based on a Perkin-Elmer C30902S-DTC SPAD.

In our circuit, the SPAD is reverse-biased through a 200kΩ resistor. This value is sufficiently large that an avalanche in the SPAD will be quenched by itself within less than a nanosecond. The pulses produced by the SPAD are AC-coupled to a fast constant-level discriminator which has an output that is compatible with TTL logic circuits. Continue reading→

Type I Downconversion Beta-Barium-Borate (BBO) Crystal Array for diy Entangled Photon Source

Posted on January 23, 2012 by David Prutchi Posted in Bell's Inequality Test, Chapter 8 - Entanglement, Entangled-Photon Source, Entanglement, Single-Photon Experiments

Photop BBO crystal array for diy entangled photon source Our diy entangled-photon source, shown in the book’s Figure 142, uses two BBO crystals that support type I down-conversion that are mounted according to a design by Paul Kwiat and his colleagues at the Los Alamos National Laboratory.

The nonlinear crystal in our photon entangler comprises two 5 mm x 5 mm x 0.1 mm BBO crystals mounted face-to-face at an angle of 90 degrees to each other. As shown in the book’s Figure 140, pump photons polarized at 45 degrees produce two cones of entangled down-converted photons.

Continue reading→

405 nm Pump Laser for diy Entangled Photon Source

Posted on January 23, 2012 by David Prutchi Posted in Bell's Inequality Test, Chapter 8 - Entanglement, Entangled-Photon Source, Entanglement, Quantum Random Number Generation, Single-Photon Experiments

405 nm UV pump laser used in diy entangled photon source

This is the 405 nm pump laser used in the circuit shown in the book’s Figure 141. The laser is built from a Blu Ray disk burner laser diode. We drive the laser diode with 160 mA to produce around 100 mW of 405-nm polarized light. The laser diode is capable of producing 250 mW, but we prefer to drive it much more conservatively. Continue reading→

diy PMT Pulse Processor Suitable For Use With “Pulse Recorder and Analyser (PRA)” MCA

Posted on January 20, 2012 by David Prutchi Posted in Chapter 2 - Light as Particles, Chapter 5 - Wave-Particle Duality, Compton Scattering, Ionizing Radiation Detection, MCA/PHA, Photomultipliers, PMT/Scintillation Processor, Scintillation Detector, Single-Photon Experiments 2 Comments

diy Photomultiplier Processor

Figure 34 in the book shows the schematic diagram for the photomultiplier tube (PMT) signal processing circuit that amplifies the narrow pulses detected by the PMT probe. The discriminator stage removes small pulses produced by thermal noise in the tube. A pulse stretcher outputs pulses that can be heard on a speaker. In addition, the analog output is suitable for use with a sound-card-based multichannel pulse-height analyzer (MCA). Continue reading→

diy Low-Cost, Regulated, Variable, Low-Ripple High-Voltage (2kV) Photomultiplier Tube Power Supply

Posted on January 20, 2012 by David Prutchi Posted in Chapter 2 - Light as Particles, Chapter 3 - Atoms and Radioactvity, Chapter 5 - Wave-Particle Duality, Compton Scattering, High-Voltage Power Supply, Ionizing Radiation Detection, MCA/PHA, Photomultipliers, Scintillation Detector, Single-Photon Experiments

The book’s Figure 32 shows the schematic diagram for a low-cost, variable-voltage PMT power supply based on a BXA-12579 inverter module that is originally designed as a power supply for cold-cathode fluorescent lamps. This under-$20 module produces 1,500VAC at around 30kHz from a 12VDC input.

We are posting this picture to help you build your own power supply. It shows the BXA-12579 that has been modified as described in the book. The op-amp to the right of the CCFL module is used to control the voltage supplied to the module. The high-voltage AC output of the inverter is rectified and doubled and filtered by the diodes and capacitors at the left of the CCFL module. Continue reading→

Beam Diagram for Entangled-Photon Source

Posted on January 14, 2012 by David Prutchi Posted in Chapter 8 - Entanglement, Entangled-Photon Source, Entanglement, Single-Photon Experiments

diy Entangled photon source described in the book "Exploring Quantum Physics through Hands-On Experiments" by David Prutchi Ph.D. and Shanni R. Prutchi

This picture supplements Figure 148 in the book. The colors should help you visualize the paths of the beams in our entangled-photon source: Violet – 405 nm pump laser beam; Pink – 810 nm signal and idler entangled-photon beams. A detailed schematic diagram for the entangler is available in the book’s Figure 147. Figure 149 shows the 405 nm beamstop. Continue reading→

RCA 6655A PMT Data Sheet

Posted on January 14, 2012 by David Prutchi Posted in Chapter 2 - Light as Particles, Chapter 3 - Atoms and Radioactvity, Chapter 5 - Wave-Particle Duality, Chapter 7 - Schrödinger's Wave Equation, Compton Scattering, Ionizing Radiation Detection, Photomultipliers, Scintillation Detector

RCA 6655A photomultiplier tube

This is the datasheet for the RCA 6655A PMT used in the probe shown in the book’s Figure 30: RCA_6655A_Datasheet

This is the datasheet for Hamamatsu’s replacement of the RCA 6655A PMT: Hamamatsu replacement for RCA 6655A R2154-02

Schematic diagrams for the probe are in Figure 29.

Assembly View of diy Variable-Output, High-Performance PMT High-Voltage Power Supply

Posted on January 14, 2012 by David Prutchi Posted in Chapter 2 - Light as Particles, Chapter 3 - Atoms and Radioactvity, Chapter 5 - Wave-Particle Duality, Chapter 7 - Schrödinger's Wave Equation, Compton Scattering, High-Voltage Power Supply, Ionizing Radiation Detection, MCA/PHA, Photomultipliers, Single-Photon Experiments

We are posting this picture to help you construct the variable-output, low-ripple, high-stability, high-voltage power supply described in pages 38-40 of “Exploring Quantum Physics Through Hands-On Projects.” The schematic diagrams for this power supply are in the book’s Figure 31. Output voltage (up to 2 kV) and current (up to 1 mA) are monitored via two LCD panel meters. Continue reading→

Compton Scattering Experiment Using Spectrum Techniques’ Equipment

Posted on January 13, 2012 by David Prutchi Posted in Chapter 5 - Wave-Particle Duality, Compton Scattering, Ionizing Radiation Detection, MCA/PHA, Scintillation Detector

Observing Compton Scattering Using the Spectrum Techniques UCS-20 MCA

Spectrum Techniques of Oak Ridge, TN – a top supplier of Exempt Quantity radioisotope sources and nuclear measurement instrumentation – released today our tutorial:

“Experiment Note: Exploring Compton Scattering Using the Spectrum Techniques Universal Computer Spectrometer” Continue reading→

quTools quED Entanglement Demonstrator

Posted on January 11, 2012 by David Prutchi Posted in Bell's Inequality Test, Chapter 8 - Entanglement, Entangled-Photon Source, Entanglement, Single-Photon Experiments

: Image Credit: quTools

quTools of München, Germany is the maker of the quED quantum entangled state demonstrator system to generate and analyze polarization entangled photons. This system is a professionally-manufactured version of the type of entangled-photon generator used by many universities, and similar to the diy version described in Chapter 8 of our book (Figure 148).

quED employs a spontaneous parametric down conversion process (type I or type II; collinear or non-collinear) to generate polarization entangled photon pairs. Fiber-coupled single photon detectors in connection with polarizing filters are used to detect the photon pairs, analyze their polarizations and verify their non-classical correlations. Continue reading→

ALPhA’s Single Photon Detector Group Order for Educational Institutions

Posted on January 11, 2012 by David Prutchi Posted in Chapter 8 - Entanglement, Entanglement, Single-Photon Counting Modules (SPCMs), Single-Photon Experiments

Excelitas Perkin-Elmer Single Photon Counting Module ALPhA (Advanced Laboratory Physics Association) has worked out a deal with Excelitas to sell Single-Photon Counting Modules (SPCMs) to instructional labs. The detectors carry labels specifying that these units belong in the undergraduate instructional labs and not in research labs. These educational detectors have reduced specs, notably a higher background dark count rate, compared to other models from the company.

The set of four SPCMs can be purchased for $5,720 (instead of the usual ~$10k). Continue reading→

Actively-Quenched SPAD SPCM Student Design Project

Posted on January 7, 2012 by David Prutchi Posted in Chapter 8 - Entanglement, Photon/Coincidence Counter, Single-Photon Counting Modules (SPCMs), Single-Photon Experiments

diy Single-Photon Counting Module designed by students at University of Illinois

Image Credit: Oliver Jan and Phil Makotyn

In 2006, then-students Oliver Jan and Phil Makotyn from University of Illinois (at Professor Paul Kwiat’s lab) developed an actively-quenched Single-Photon Counting Module (SPCM) based on the Perkin-Elmer C30902S-DTC Single-Photon Avalanche Photodiode (SPAD). Continue reading→

β-Particle Magnetic Deflection Experiment – Supplementary Pictures

Posted on January 5, 2012 by David Prutchi Posted in CDV700 Pro Geiger-Müller Counter, Chapter 3 - Atoms and Radioactvity, Ionizing Radiation Detection, β-Particle Magnetic Deflection

β-Particle Magnetic Deflection Experiment

The book’s Figure 65 shows our β-particle magnetic deflection setup. It consists of a ⁹⁰Sr disc source of beta particles, two copper washers to collimate the beam, and GM tubes placed at 0º and 90º to the β-particle beam. A sufficiently strong magnetic field (around 800 Gauss = 0.08 Tesla) provided by a permanent magnet bends the beam so much that it is easily detected at a right angle (notice the meter needles in the pictures above).

Continue reading→

Attenuation of Alpha, Beta and Gamma Radiation in Air

Posted on January 5, 2012 by David Prutchi Posted in Attenuation of Radiation, CDV700 Pro Geiger-Müller Counter, Chapter 3 - Atoms and Radioactvity, Ionizing Radiation Detection

Measurement of alpha, beta, and gamma radiation by air as a function of distance

The attenuation of radiation as a function of distance can be measured using a radiation counter with a Geiger-Müller tube that is sensitive to α, β, and γ radiation. We used exempt plastic-disc sources containing Polonium 210 (²¹⁰Po), Strontium 90 (⁹⁰Sr), and Cobalt 60 (⁶⁰Co) to experiment with the penetrating power of α, β, and γ radiation in air. Continue reading→

Color Spectrograph Using Spectrometer of Figure 80

Posted on January 5, 2012 by David Prutchi Posted in Chapter 4 - The Priciple of Quantum Physics, Emission Spectrometry, Spectrometer

Color spectrographs using the spectrometer described by Prutchi in "Exloring Quantum Physics Through Hands-On Projects"

These two images supplement the book’s Figure 81. They were taken with the spectrometer of Figure 80.