diy Physics Blog

Category Archives: Instrumentation

OpenQuantum’s DIY Open-Source Magneto-Optical Atomic Trap

Posted on by Posted in Magneto-Optical Trap, Vacuum System
Open-source magneto-optical atomic trap by OpenQuantum

Image Credit: OpenQuantum

Last weekend, Max Shirokawa Aalto presented his OpenQuantum project at the 2023 Hackaday Superconference.  OpenQuantum’s platform is a fully open-source magneto-optical trap which can be used to collect, control, and manipulate ultracold rubidium atoms.

The design is fully open-source, and includes all the CAD files, machining instructions, electronics schematics, PCB files, firmware, and software necessary to build the apparatus for around $8k, which is significantly cheaper (by two orders of magnitude) than commercial solutions.

In his excellent talk, Max introduced the principle of atomic cooling and trapping using magnetic fields and lasers.  He then discussed the 3D-printed laser and system for observing the absorption spectrum of atoms, and touched on the high-vacuum system needed for a fully-operational trap.

Max envisions OpenQuantum to be a platform that can be used for teaching Quantum Mechanics, as well as the basis for developing new quantum technologies.  Max is looking for collaborators for his exciting project.  You may contact him at: team@open-quantum.org

The following YouTube video shows the talk that Max presented  at the Quantum Village at DEFCON 31:

In Memoriam: Robert (Bob) Iannini (1938-2023)

Posted on by Posted in Administrative, High-Voltage Power Supply, Instrumentation, Lasers, Marx Generators
Robert (Bob) Iannini, inventor, author, and founder of Information Unlimited

Image Credit: Information Unlimited

I recently learned the saddening news of the passing of Robert (Bob) Iannini on April 3, 2023, just shy of his 85th birthday. Bob, an extraordinary inventor, celebrated book author, and the mastermind behind “Information Unlimited,” succumbed to pneumonia, leaving a void in the world of amateur science and electronics.

From my high school days, Bob’s innovative paper plans and kits were my constant companions. They were more than just gadgets and devices; they were a gateway into the magical world of out-of-the-ordinary electronics, a world where possibilities seemed endless. Those kits, along with his captivating books, were my stepping stones into understanding the nuances of the ever-fascinating realm of high voltage, ultrasonics, and lasers. They nurtured my curiosity and fueled my passion.

Bob’s genius was evident in every project he conceived and every kit he designed. But beyond his brilliance, he had an innate ability to inspire young minds like mine. He made these very complex topics approachable, fun, and endlessly intriguing. With each of his creations, he imparted a sense of wonder that drove many of us to push boundaries and think beyond the conventional.

“Information Unlimited” was more than just a business; it was Bob’s legacy. It was a beacon for those with an insatiable thirst for knowledge, serving as a treasure trove of information, ideas, and inspiration for enthusiasts of all ages. In light of Bob’s passing, his wife Ann informed me that “Information Unlimited” had to be temporarily closed. However, with resilience and hope, Ann aspires to reopen its doors in just a few months, ensuring that Bob’s legacy continues to shine brightly and inspire many more.

As I reflect upon his remarkable journey, I can’t help but feel an overwhelming sense of gratitude. Bob Iannini’s indelible impact on amateur scientists, hobbyists, and curious minds across the world will forever resonate.

To Bob, thank you for igniting the flames of curiosity in countless souls. You may have departed from this world, but your legacy will continue to inspire generations to come.

A Custom Base for using the EMI/Thorn 9816B Photomultiplier Tube with the Products for Research Model TE-182 Thermoelectrically-Cooled PMT Housing for Ultra-Low Light Level Experiments

Posted on by Posted in Photomultipliers, PMT/Scintillation Processor

For a detailed writeup in pdf format please CLICK HERE

I’ve been planning some experiments with single-photon and ultra-low light levels. For these experiments I want the collection area to be large and for the detector to have very broad spectral response, so my preference is to use a photomultiplier tube (PMT) instead of a “silicon photomultiplier” avalanche single-photon detector.

I found a brand new EMI 9816B PMT on eBay® which meets my requirements. The 9816B is a 51 mm (2”) diameter end-window photomultiplier, with an S20 infrared-sensitive photocathode, and 14 BeCu dynodes of linear focused design. This tube features a very high gain of 25×106 A/lm under nominal conditions (2,200V) with a quantum efficiency of 21% at the peak response wavelength.

Integration time, and ultimately resolution and sensitivity for detecting single-photons or ultra-weak light levels are dependent on the noise floor (dark counts) which is a function of temperature. Cooling the PMT dramatically reduces its dark current and counts.

I bought a surplus thermoelectrically-cooled housing by Products for Research (Model TE-182) which is made for 2” end-window PMTs. I could not find a surplus base for the EMI 9816B 14-dynode PMT, so I decided to buy a surplus base for a different tube and modify it for the 9816B.

Products for Research TE-182 Thermoelectrically-Cooled Housing for 2″ PMTs

Clearing the inside of the base was a very messy affair. This is because the dynode voltage divider chain is partially potted in silicone, and the rest of the base is filled with expanding thermal-isolation foam. Part of the base is made of plastic, so the use of harsh chemical solvents or heat to remove the silicone rubber and expanding foam were not possible. I thus had to use a scalpel and dental picks to remove all this insulation and be able to disassemble the tube socket.

I built a new divider on a piece of phenolic breadboard . The base is wired for high voltage (-2,300V) applied to the cathode (through a 33kΩ resistor). The dynode_1-to-dynode_14 divider is built with 330kΩ resistors. As suggested by EMI, the cathode-to-focus (and dynode_1) is set at a fixed 300V difference using two 150V Zener diodes in series.

Results from a characterization run are shown in the following table. The room-temperature dark current agrees with the specified value. A very dramatic drop in dark current and dark count rate can be observed when the PMT is cooled.

For a detailed writeup in pdf format please CLICK HERE

Elegant Experiment to Measure Planck’s Constant using Photons from Distant Star

Posted on by Posted in Chapter 2 - Light as Particles, PMT/Scintillation Processor

Javier De Elias Cantalapiedra from Madrid, Spain posted the YouTube video above to show his very elegant experiment in which he measured Planck’s constant using photons from a distant star.  As in the e/m measurement he had previously shared with us, his experimental technique is very rigorous, which yielded Planck’s constant with just 5% error.  This is remarkable given the method he applied.

Javier is an industrial engineer who works in the telecommunications industry.  However, his passion is physics, which he pursues at a (very high) amateur level.

Thank you Javier for sharing!

Febetron/Fexitron Marx Bank Module

Posted on by Posted in High-Voltage Power Supply, Marx Generators

I have kept on making space in my lab for new projects, and came across 3 new-old-stock Marx generator modules that were made for the Fexitron and Febetron flash X-ray sources and electron accelerators. The Fexitron and Febetron devices were made in the 1970s by the Field Emission Corporation, a division of HP, which is now L-3 Pulse Sciences.

Each module contains two complete 30 kV Marx stages. In the Febetron/Fexitron pulsers, modules were stacked to form Marx generators of up to 2.3MV output. The spark gap distance is adjustable. These modules are designed for use under 20-70 psi air or nitrogen.

My intention was to build a 180 kV fast Marx with these, so I had reverse-engineered the schematic for these modules. I’m putting it here in case that someone is interested.

The following are interesting links related to Fexitron/Febetron units:

 

Converting a 1980s Video Camera into a Real-Time Polarimetric Imager

Posted on by Posted in Polarimetric Imaging

Real-time polarimetric imaging camera by David Prutchi Ph.D.

Three years ago I developed the DOLPi polarimetric cameras  based on the Raspberry Pi. One used an electro-optical polarization analyzer, while the other used discrete polarization filters mounted on a filter wheel. The only issue with their performance was lack of speed.  I mentioned back then that high-speed polarization imagers have been built using multiple sensors, each with its dedicated, fixed-state polarization analyzer.  I finally got around to converting a 1980s-era three-tube camera into a real-time polarimetric imager.  The full whitepaper with detailed step-by-step instructions is available for download in pdf format at:  Converting_the_JVC_KY-1900_into_a_Real-Time_Polarimetric_Imager_-_Prutchi_2018

Continue reading→

Rebuild of my diy Image Intensifier System for QP Experiments

Posted on by Posted in Chapter 2 - Light as Particles, Single-Photon Experiments, Single-Photon Imaging, Two-Slit Interference

After many years of use, the image intensifier tube (IIT) in the image intensifier system that I use for my experiments in quantum physics developed some nasty half-moon shadows in the periphery, so I decided to rebuild it with another MX-10160-type IIT.  I documented the build in the following document: diy Image Intensifier System Prutchi

Thermal Camera diy Macro and Telephoto Converters Posted to UVIRimaging.com

Posted on by Posted in Medium Wave Infrared Imaging, Thermal Camera

I recently purchased a Seek RevealPro Thermal Camera, which boasts a 320 x 240 thermal sensor with >15 Hz frame rate at an incredibly affordable price.

One of the only issues that I have with this camera is that it comes with a fixed 32° field-of-view lens. This is OK for general thermal inspection, but it’s a real disadvantage when trying to use the camera for close-up work to assess dissipation on printed circuit boards, or for identifying a faulty or undersized component. On the opposite side of the distance range, the 32° FOV lens makes it difficult to see and measure the temperature of objects at a distance, or of smaller objects at normal distances.

I thus decided to build magnifying (“macro”) and close-up (“telephoto”) converters for the RevealPro. I’m passing along information on my designs in hopes that others will find it useful.  Detailed instructions in the following whitepaper: Diy-Thermal-Camera-Telephoto-Converter

Posted to UVIRimaging.com: diy LW, MW, SW Ultraviolet Lamp for UV Fluorescence Photography

Posted on by Posted in Ultraviolet Illuminators

diy LW MW SW Ultraviolet lamp by David Prutchi PhD

I just posted a new whitepaper with a short primer on UV Fluorescence Photography and a diy 18W, 3-wavelength, professional-grade lamp.

Hackmanite UV fluorescence David Prutchi PhD
The figure above shows pictures of Hackmanite from Bancroft, Ontario, Canada taken using this diy lamp: a) White light photograph; b) reflected near-UV with Baader-U and long-wave illumination; c) fluorescence with wideband (LW, MW and SW) excitation; d) long-wave UV excitation; e) fluorescence with mid-wave UV excitation; f) fluorescence with short-wave UV excitation.

The whitepaper is available at: http://uvirimaging.c…ce-photography/

 

 

iPhone-based DOLPi Polarimetric Camera Developed by Paul Wallace

Posted on by Posted in Polarimetric Imaging
iPhone DOLPi Camera

iPhone DOLPi Camera developed by Paul Wallace

Reader Paul Wallace contacted me to tell me about the DOLPi electro-optic polarization camera that he built for his iPhone. His ingenious solution makes use of the iPhone’s flashlight to calibrate and synchronize the control of the polarization analyzer (hacked from a welder’s mask as described in the DOLPi whitepaper).

Continue reading→

DOLPi Visor Replication by Andrew Gliesman

Posted on by Posted in Polarimetric Imaging

DOLPi Visor replication by Andrew GliesmanAndrew Gliesman sent me these pictures of his DOLPi Visor replication along with a very kind note.

…I wanted to thank you for your excellent paper on the DOLPi Polarimetric Camera.  The amount of technical detail combined with providing a solution of a real world humanitarian problem made it special to me.

I recently built a DOLPi Visor and wanted to share my alternative form-factor with you (see photos.)  With respect to the build notes, everything was spot on – I just found that I needed to clean the adhesive residue after removing a polarizer film on the LCP (perhaps this had to do with the brand – I couldn’t find the MASK brand on Amazon.)…

The point about the adhesive is interesting.  Indeed, the adhesive remains transparent after removing the polarizer film, but becomes cloudy if scratched.  I found that the best way to remove it is to loosen it with a drop of “Goof-Off” and then scraping it with a sharp razor blade.

Thanks Andrew!

DOLPi Visor replication by Andrew Gliesman

 

Video of Shanni’s Lecture on Entangled Photon Generation at HaD SuperCon

Posted on by Posted in Entangled-Photon Source, Entanglement, QKD, Single-Photon Counting Modules (SPCMs)

Shanni_HaD_IMG_2111_600px

Shanni presented on “Construction of an Entangled Photon Source for Experimenting with Quantum Technologies” at the 2015 Hackaday SuperConference.

Her lecture has been uploaded by Hackaday and is available now available online.  CLICK HERE for the link to the HaD Blog and Video.

Shanni Prutchi presents at HaD SuperCon on Entangled Photon Generation

 

DOLPi – A Low-Cost RasPi-based Polarization Camera

Posted on by Posted in Polarimetric Imaging

DOLPi – A Low-Cost RasPi-based Polarization Camera

A polarimetric imager to detect invisible pollutants, locate landmines, identify cancerous tissues, and maybe even observe cloaked UFOs!

DOLPi Polarimetric camera by David Prutchi, Ph.D. www.diyPhysics.com

The polarization of light carries interesting information about our visual environment of which we are usually unaware. Some animals have evolved the capability to see polarization as a distinct characteristic of light, and rely critically on this sense for navigation and survival. For example, many fish, amphibians, arthropods, and octopuses use polarization vision as a compass for navigation, to detect water surfaces, to enhance the detection of prey and predators, and probably also as a private means to communicate among each other.

While we have used technology to expand our vision beyond the limits of our ordinary wavelength and intensity sensitivities, the unintuitive nature of polarization has slowed down the development of practical applications for polarization imaging. Polarization cameras do exist, but at over $50,000, they are mostly research curiosities that have found very few practical uses outside the lab.

The DOLPi project aims to widely open the field of polarization imaging by constructing a very low cost polarization camera that can be used to research and develop game-changing applications across a wide range of fields – spanning all the way from environmental monitoring and medical diagnostics, to security and antiterrorism applications.

The DOLPi polarization camera is based on a standard Raspberry Pi 2 single-board computer and its dedicated 5MP camera. What makes the DOLPi unique is that the camera sits behind a software-controlled electro-optic polarization modulator, allowing the capture of images through an electronic polarization analyzer. The modulator itself is hacked from two low-cost auto-darkening welding mask filters ($9 each). In spite of its simplicity, DOLPi produces very high quality polarization images.

This is a first-of-its-kind project! I am not aware of any polarization imager ever presented as an enthusiast-level DIY project, yet it holds truly awesome disruptive power for the development of brand new scientific and commercial applications!

A complete description of this project in pdf format is available at: DOLPi_Polarimetric_Camera_D_Prutchi_2015_v2

Continue reading→

$25 Philips Medical Systems PMTs from Sphere Research

Posted on by Posted in Photomultipliers

Low-Cost Scintillation Probe Based on a Surplus XP3312 PMT for Ludlum Ratemeters www.diyPhysics.com prutchiSphere Research is clearing out all the Philips PMT assemblies they have in stock to empty their expensive off-site rental storage space. While stock is available, you can order any PMT shown as a Philips Medical Systems assembly at the beginning of this page for only $25 +shipping:

http://www.sphere.bc.ca/test/photo-tubes.html

Simply identify the deal as coming from DIY Physics when ordering (Note from diyPhysics.com: nothing in it for us except passing along some great info…).

All these tubes will be cleared out shortly so they can close down their over-priced off-site rental storage space. The offer is limited to stock on hand at the time of order. Sphere Research is happy to consolidate orders and help you minimize shipping costs wherever possible.  They can take Visa, MasterCard and PayPal for orders. These are very high performance tubes and hard to find, but they are very awkward for them to store in the big factory boxes, so they have to go.