From Saturday Morning B
In my prior post I told about components in my CO2 laser’s RF power supply becoming unsoldered when they overheated. After the repair, I needed some way of retuning the RF output stage for maximum laser output. This motivated me to build the power sensor shown in the picture above. Read more…
I was thinking about buying a laser engraver/cutter for home, but after retrofitting for CNC the Micro-Mark mini mill that my wife gave me for my birthday, I figured that I could simply add a CO2 laser to the X2 mini mill.
Before describing the mod, I figured you would want to see some results. Here is a YouTube video of my X2 mini-mill laser engraver in action: Read more…
Home-Made Radiac Turns Surplus Military Scintillation Probes into Sensitive, General-Purpose Gamma Radiation Counter
Military-surplus scintillation probes meant for the detection of plutonium contamination are widely available in the surplus market. The DT590A/PDR-56F “Plutonium-239 Contamination X-Ray Probe” was used with the PDR-56 Radiac Set (radiation detection and measurement instrument), that has been obsoleted by the US Air Force.
The probe is designed specifically for detecting the 14 to 21 keV gamma lines emitted by Plutonium-239 along with its main alpha-particle emissions. For this reason, despite its availability in the surplus market, this probe has not found wide acceptance by science enthusiasts interested in radiation counters.
I just posted to www.diyPhysics.com detailed instructions for the construction of my home-built PDR-56-like radiac set capable of driving a surplus DT590A/PDR-56F “Plutonium-239 Contamination X-Ray Probe.” In addition, I also give instructions on how to open the single-channel analyzer window to convert the instrument into a very sensitive, general-purpose gamma radiation counter. Read more…
Some time ago I was developing a medical instrument which required histogramming, which got me in the mood to retake my own PIC MCA project(http://home.comcast.net/~prutchi/index_files/scint.htm ). I used the variable RAM in the microcontroller (16F877), so I limited the number of channels to 95 and let the histogram run until some channel reaches 240 counts (the highest 8-bit number that yields an integer when divided by 8). The firmware then displays the spectrum as a bar with a maximum height of 30 pixels for each one of the 95 channels.
Click here for complete how-to construction instructions in pdf format.
Click here for a pdf of the schematic diagram for the front-end of the MCA
Today we received the first two copies of our new book! It is a do-it-yourself book on Experimental Quantum Physics, and was published by John Wiley & Sons.
From the back cover:
“Build an intuitive understanding of the principles behind quantum mechanics through practical construction and replication of original experiments.
With easy-to-acquire, low-cost materials and basic knowledge of algebra and trigonometry, Exploring Quantum Physics through Hands-on Projects takes readers step by step through the process of re-creating scientific experiments that played an essential role in the creation and development of quantum mechanics.
Presented in near chronological order—from discoveries of the early twentieth century to new material on entanglement—this book includes question- and experiment-filled chapters on:
- Light as a Wave
- Light as Particles
- Atoms and Radioactivity
- The Principle of Quantum Physics
- Wave/Particle Duality
- The Uncertainty Principle
- Schrödinger (and his Zombie Cat)
From simple measurements of Planck’s constant to testing violations of Bell’s inequalities using entangled photons, Exploring Quantum Physics through Hands-on Projects not only immerses readers in the process of quantum mechanics, it gives them insight into the history of the field—how the theories and discoveries apply to our world not only today . . . but also tomorrow.
By immersing readers in groundbreaking experiments that can be performed at home, school, or in the lab, this first-ever, hands-on book successfully demystifies the world of quantum physics for all who seek to explore it—from science enthusiasts and undergrad physics students to practicing physicists and engineers.”
For more information, please visit our d.i.y. Modern/Quantum Physics projects website at: www.diyPhysics.com
Our space-communicationsantenna array includes a camera that looks in the direction that the array is pointing. This camera helps us check that we are aiming directly at the moon during EME attempts. In addition, when it lets us see airplanes that may be the source of interfering signals when we conduct radio-astronomy observations. Read more…
This is a hack that combines three of my favorite passions: pacemakers, photography, and coffee!
I took this photograph by feeding the output of an infrared barrier to the atrium input of an old DDD pacemaker, setting an appropriate AV delay, and using the ventricular output to trigger a camera flash (via a optoisolator). In a darkened room, I opened my camera’s shutter for 2 seconds. I then let one drop of milk fall through the infrared barrier, starting the AV delay in VAT mode. The flash then fires as the drop enters the coffee in the cup, freezing the action. Read more…
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” Read more…
Lately I’ve received many inquiries about the paper on radiation-hardness testing of implantable integrated circuits that I published with Dr. Larry Stotts (now Executive VP R&D at Biotronik), and the late Dr. John Prince. This is because the effects of medical diagnostic and therapeutic radiation are becoming an issue of concern to physicians who often encounter the need for radiotherapy in the growing population of patients implanted with pacemakers, defibrillators, neural stimulators, and drug-delivery pumps.
Although the paper reported mainly on the test of floating-gate EEPROMs, the modern interest is on the test methods that we developed to test ICs used in implantable devices for hardness to the type of radiation encountered in the medical field.
Click here for our paper: D. Prutchi, J.L. Prince and L.J. Stotts, “X- and Gamma-Ray Hardness of Floating-Gate EEPROM Technology as Applied to Implantable Medical Devices”, IEEE Transactions on Electronic Components and Packaging Technology, 22(3), 390-398, 1999.
Note: Cross-posted at www.implantable-device.com