Large area x-ray detector

This is an x-ray detector built by [Ben Krasnow]. It’s an interesting combination of parts working with an oscilloscope. The result is an audible clicking much the same as you would hear from a Geiger counter

He’s measuring backscatter, which is the reflection of x-rays on other objects. Because the signal will be quite weak compared to waves emitted directly from an x-ray source he needed a large collector to measure them. He started by gutting an x-ray image intensifying cassette. This has a phosphor layer that glows when excited by x-rays. The idea is that the glowing phosphors do a better job of exposing film than direct x-rays can. But [Ben’s] not using film. He built that pyramid-shaped collector with the phosphor material as the base. At the apex of the pyramid he mounted a photomultiplier tube (repurposed from his scanning electron microscope) which can detect the excited points on its surface. His oscilloscope monitors the PMT, then issues a voltage spike on the calibration connector which is being fed to an audio amplifier. Don’t miss his presentation embedded after the break.

[Ben] mentions that this build is in preparation for a future project. We’d love to hear what you think he’s working on. Leave your guess in the comments section.

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Building an x-ray machine and letting everything go to your head

It’s not every day one of the builds on Hackaday gets picked up by a big-name publication, and it’s even rarer to see a Hackaday contributor grace the pages of an actual print magazine. Such is the case with [Adam Munich] and his home-built x-ray machine.

We first saw [Adam]’s x-ray machine at the beginning of this year as an entry for the Buildlounge/Full Spectrum laser cutter contest. [Adam] won the contest, landed himself a new laser cutter, and started writing for Hackaday. Now that [Adam] is gracing the pages of Popular Science, we’re reminded of the story of Icarus, flying too close to the sun.

[Adam]’s x-ray machine is built around a Coolidge tube, the same type of vacuum tube found in dental x-ray machines. The device is housed in two suitcases – one used as a control panel and graced with beautiful dials and Nixies, the other housing the Coolidge tube and power supply. Proper x-ray images can be taken by pointing a camera at the scintillation screen, allowing [Adam] to see inside hard drives and other inanimate objects.

Sure, it’s a build we’ve seen before but it’s still very cool to see one of Hackaday’s own get some big name recognition.

[Grenadier] wins the laser cutter for his portable X-ray project

The results of the Full Spectrum Laser contest over at Build Lounge have been announce. The top prize of a 40 watt deluxe laser cutter goes to [Grenadier] for the portable x-ray machine we saw at the beginning of the month. We think this is an excellent choice for top prize because, come on, this is pretty hard-core.

Taking second place was a Christmas light show choreographed to music. The open spaces of the University of Minnesota hosted the installation. We’ve embedded a video of the performance after the break.

Third prize went to the QC Co-lab Hackerspace for their light wall. It uses the ever popular GE Color Effects lights, with each bulb housed in a vacuum formed pyramid which acts as a diffuser.

There were also several honorable mentions. There’s a special place in our heart for [Jack Buffington’s] solar clock which was included in this group. We think the use of fiber optics to pipe the sunlight into a machined index ring is ingenious. And you’ve got to give him credit for developing a project that uses no electricity and almost no moving parts (there is a slider to adjust for daylight savings time).

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See through everything with a home made x-ray

[Grenadier] built his very own x-ray machine. He’s no stranger to high voltage – we’ve seen his Jacob’s Ladders and Marx generators. Surely he can handle himself with high voltage and dangerous equipment. With this portable x-ray machine, [Grenadier] has begun overloading Geiger counters. We’re just happy he knows what he’s doing.

The key component of [Grenadier]’s portable x-ray machine is the Coolidge tube, a simple vacuum tube that produces x-rays with the help of 75 kilovolts of power. The finished build looks awesome. Two meters display the milliamps and kilovolts going to the x-ray tube, and a trio of nixies display the exposure time.

Even though [Grenadier] doesn’t have x-ray film, he can see through things with a scintillation screen that fluoresces when exposed to ionizing radiation. There are two pictures of the x-ray in action – one showing the inside of a pen and the guts of a hard drive (as shown in the title pic).

The output of the x-ray was measured with a Geiger counter. [Grenadier] was able to get a hit every second or so at 50 yards, and very loud white noise at 1 foot. Check out the video of [Grenadier]’s Buildlounge laser cutter contest submission after the break.

via Buildlounge

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Rapatronic shutter; snap a pic of an atomic bomb

We never really thought about it before, but this post about Rapatronic Shutters answers the question of how to photograph an atomic bomb detonation. The post includes an MIT video where [Charles Wyckoff] explains how he and [Harold Edgerton] developed the Rapatronic Camera. It is designed to snap a photograph based on zero time, marked by the X-ray transmission emanating from the bomb before it actually explodes. This pulse is picked up by a light sensor on a delay circuit, allowing for very precise exposure timing. Many of these cameras were used at the same time, all with slightly different delays so that the images could be viewed in order to show what happens during each stage of detonation.

[Thanks Petrus]