Neutrino Hunters Hack Chat

January 15, 2024 by Dan Maloney 1 Comment

Join us on Wednesday, January 17 at noon Pacific for the Neutrino Hunters Hack Chat with Patrick Allison!

It’s a paradox of science that the biggest of equipment is needed to study the smallest of phenomena. The bestiary of subatomic particles often requires the power and dimension of massive accelerators to produce, and caverns crammed with racks full of instruments to monitor their brief but energetic lives. Neutrinos, though, are different. These tiny, nearly massless, neutral particles are abundant in the extreme, zipping through space from sources both natural and artificial and passing through normal matter like it isn’t even there.

That poses a problem: how do you study something that doesn’t interact with the stuff you can make detectors out of? There are tricks that neutrino hunters use, and most of them use very, VERY big instruments to do it. Think enormous tanks of ultrapure water or a cubic kilometer of Antarctic ice, filled with photomultiplier tubes to watch for the slightest glimmer of Cherenkov radiation as a neutrino passes by.

Neutrino hunting is some of the biggest of Big Science, and getting all the parts to work together takes some special engineering. Patrick Allison has been in the neutrino business for decades, both as a physicist and as the designated guru who keeps all the electronics humming. He’ll join us on the Hack Chat to talk about the neutrino hunting trade, and what it takes to keep the data flowing.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, January 17 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

Featured image: Daderot, CC0, via Wikimedia Commons

Detecting Neutrinos, The Slippery Ghost Particles That Don’t Want To Interact

November 14, 2023 by Lewin Day 62 Comments

Neutrinos are some of the most elusive particles that are well-known to science. These tiny subatomic particles have no electric charge and an extremely small mass, making them incredibly difficult to detect. They are produced in abundance by the sun, as well as by nuclear reactions on Earth and in supernovae. Despite their elusive nature, scientists are keen to detect neutrinos as they can provide valuable information about the processes that produce them.

Neutrinos interact with matter so rarely that it takes a very special kind of detector to catch them in the act. These detectors come in a few different flavors, each employing its unique method to spot these elusive particles. In this article, we’ll take a closer look at how these detectors work and some of the most notable examples of neutrino detectors in the world today.

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Detecting Anti-Neutrinos From Distant Fission Reactors Using Pure Water At SNO+

April 16, 2023 by Maya Posch 32 Comments

Although neutrinos are exceedingly common, their near-massless configuration means that their presence is rather ephemeral. Despite billions of them radiating every second towards Earth from sources like our Sun, most of them zip through our bodies and this very planet without ever interacting with either. This property is also what makes studying these particles that are so fundamental to our understanding so complicated. Fortunately recently published results by researchers behind the SNO+ neutrino detector project shows that we may see a significant bump in our neutrino detection sensitivity.

The Sudbury Neutrino Detector (Courtesy of SNO)

In their paper (preprint) in APS Physical Review Letters, the researchers describe how during the initial run of the new SNO+ neutrino detector they were able to detect anti-neutrinos originating from nuclear fission reactors over 240 kilometers away, including Canadian CANDU and US LWR types. This demonstrated the low detection threshold of the SNO+ detector even in its still incomplete state between 2017 and 2019. Filled with just heavy water and during the second run with the addition of nitrogen to keep out radioactive radon gas from the surrounding rock of the deep mine shaft, SNO+ as a Cherenkov detector accomplished a threshold of 1.4 MeV at its core, more than sufficient to detect the 2.2 MeV gamma radiation from the inverse beta decays (IBD) that the detector is set up for.

The SNO+ detector is the evolution of the original Sudbury Neutrino Observatory (SNO), located 2.1 km below the surface in the Creighton Mine. SNO ran from 1999 to 2006, and was part of the effort to solve the solar neutrino problem, which ultimately revealed the shifting nature of neutrinos via neutrino oscillation. Once fully filled with 780 tons of linear alkylbenzene as a scintillator, SNO+ will investigate a number of topics, including neutrinoless double beta decay (Majorana fermion), specifically the confounding question regarding whether neutrinos are its own antiparticle or not

The focus of SNO+ on nearby nuclear fission reactors is due to the constant beta decay that occurs in their nuclear fuel, which not only produces a lot of electron anti-neutrinos. This production happens in a very predictable manner due to the careful composition of nuclear fuel. As the researchers noted in their paper, SNO+ is accurate enough to detect when a specific reactor is due for refueling, on account of its change in anti-neutrino emissions. This is a property that does not however affect Canadian CANDU PHWRs, as these are constantly refueled, making their neutrino production highly constant.

Each experiment by SNO+ produces immense amounts of data (hundreds of terabytes per year) that takes a while to process, but if these early results are anything to judge by, then SNO+ may progress neutrino research as much as SNO and kin have previously.

Anatomy Of A Fake CO2 Sensor

February 18, 2023 by Jenny List 44 Comments

The pandemic brought with it a need to maintain adequate ventilation in enclosed spaces, and thus, there’s been considerable interest in inexpensive C02 monitors. Unfortunately, there are unscrupulous actors out there that have seen this as a chance to make a quick profit.

Recently [bigclivedotcom] got one such low-cost CO2 sensor on his bench for a teardown, and confirms that it’s a fake. But in doing so he reveals a fascinating story of design decisions good and bad, from something which could almost have been a useful product.

Behind the slick color display is a PCB with an unidentified microcontroller, power supply circuitry, a DHT11 environmental sensor, and a further small module which purports to be the CO2 sensor. He quickly demonstrates with a SodaStream that it doesn’t respond to CO2 at all, and through further tests is able to identify it as an alcohol sensor.

Beyond the alcohol sensor he analyses the PSU circuitry. It has a place for a battery protection chip but it’s not fitted, and an error in the regulator circuitry leads to a slow drain of the unprotected cell. Most oddly there’s an entire 5 volt switching regulator circuit that’s fitted but unused, being in place to support a missing infra-red module. Finally the screen is an application-specific LCD part.

It’s clear some effort went in to the design of this unit, and we can’t help wondering whether it could have started life as a design for a higher-spec genuine unit. But as [Clive] says, it’s a party detector, and of little more use than as a project case and battery.

Need more dubious instrumentation? How about a magnetic field tester?

Continue reading “Anatomy Of A Fake CO2 Sensor” →

Excuse Me, Your Tie Is Unzipped

January 5, 2023 by Al Williams 102 Comments

If you ask your typical handyperson what’s the one thing you need to fix most things, the answer might very well be duct tape. But second place — and first place in some circles — would have to be zip ties. These little wonders are everywhere if you look for them. But they are a relatively recent invention and haven’t always had the form they have today.

The original zip tie wasn’t called a zip tie or even a cable tie. In 1958 they were called Ty-Raps and produced by a company called Thomas and Betts. Originally meant to improve aircraft wiring harnesses, they found their way into various electronic equipment and packaging uses. But they’ve also become helpful in very unusual places too. A policeman trying to round up rioters would have problems carrying more than a few conventional handcuffs. But flexible cuffs based on zip ties are lightweight and easy to carry. Colon surgeons sometimes use a modified form of zip tie during procedures.

History

Maurus Logan worked for the Thomas and Betts company. In 1956, he was touring an aircraft manufacturing plant. Observing a wiring harness being put together on a nail board, similar to how car harnesses are made, he noted that the cables were bundled with waxed twine or nylon cord. A technician had to tie knots in the cord, sometimes cutting their fingers and often developing calluses. In addition, the twine was prone to fungal growth, requiring special treatment.

Logan kept turning the problem over in his mind and tried various approaches. By 1958, he had a patent for the Ty-Rap. The tie was lightweight, easy to install, easy to remove, and inexpensive.

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Detecting Alpha Particles Using Copper Wire And High Voltage

January 22, 2022 by Robin Kearey 14 Comments

If you want to measure radioactivity, nothing really beats a Geiger counter: compact, rugged, and reasonably easy to use, they’re by far the most commonly used tool to detect ionizing radiation. However, several other methods have been used in the past, and while they may not be very practical today, recreating them can make for an interesting experiment.

[Mirko Pavleski] used easily obtainable components to build one such device known as an alpha radiation spark detector. Invented in 1945, a spark detector contains a strong electric field into which discharges are triggered by ionizing radiation. Unlike a Geiger-Müller tube, it uses regular air, which makes it sensitive only to alpha radiation; beta and gamma rays don’t cause enough ionization at ambient pressure. Fortunately, alpha radiation is the main type emitted by the americium tablets found in old smoke detectors, so a usable source shouldn’t be too hard to find.

The construction of this device is very simple: a few thin copper wires are suspended above a round metal can, while a cheap high-voltage source provides a strong electric field between them. Sparks fly from the wires to the can when an alpha source is brought nearby; a series resistor limits the current to ensure the wires don’t overheat and melt.

Although not really practical as a measurement device, the spark detector can nevertheless be used to perform simple experiments with radioactivity. As an example, [Mirko] demonstrates in the video embedded below that alpha particles are stopped by a piece of paper and therefore present no immediate danger to humans. The high voltage present in the device does however, so care must be taken with the detector more than with the radiation source.

We’ve seen several homebrew Geiger counters, some built with plenty of duct tape or with the good old 555 timer. But you can also use photodiodes or even certain types of plastic to visualize ionizing radiation.

Continue reading “Detecting Alpha Particles Using Copper Wire And High Voltage” →