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MIT's New Tabletop Particle Detector Sees Individual Electrons
An anonymous reader writes: Scientists at MIT have created a small, tabletop particle detector capable of identifying individual electrons within a cloud of radioactive gas. "As the radioactive krypton gas decays, it emits electrons that vibrate at a baseline frequency before petering out; this frequency spikes again whenever an electron hits an atom of radioactive gas. As an electron ping-pongs against multiple atoms in the detector, its energy appears to jump in a step-like pattern." The researchers used the detector to record the activity of 100,000 different electrons within the gas (abstract). They're hoping that with enough data about how the electrons bounce around, they'll be able to pinpoint the amount of energy released during these krypton atom decay events. Once they know how much energy is released, they can figure out the mass of a neutrino, which is also emitted during the decay.
""26 gigahertz,” Formaggio says."
Actually, his name is Joe.
ECR is fascinating to some of us... actually, very few of us.
However, one statement in the article about another experiment is horribly wrong:
“In KATRIN, the electrons are detected in a silicon detector, which means the electrons smash into the crystal, and a lot of random things happen, essentially destroying the electrons,” says Daniel Furse..."
No,no,no,no,NO!
The Beta particles get slowed down, trapped, and captured, and one or more neighboring electrons cascade out and eventually escape the Detector, to be counted. This is the principle behind Surface Barrier Detectors.
Sheesh!
Do electrons actually vibrate?
No.
The electrons emit cyclotron radiation, because they are being accelerated by a magnetic field. The acceleration is always perpendicular to the electron's velocity vector, so they don't speed up, they just turn in a circle. However, all accelerating charges emit electromagnetic radiation, and in the case of an electron moving in a magnetic field in this fashion it is called "cyclotron radiation". In other contexts it is called "bremsstrahlung", and so on. Physicists often have multiple names for the same basic phenomenon manifesting itself in different circumstances.
Add "electrons vibrate" or "everything vibrates" to this account adds nothing and obscures the actual source of the radiation, which is continuity conditions on the electro-magnetic field. These conditions are described by Maxwell's Equations, which predict such radiation. There is exactly nothing in Maxwell's Equations that could be said to describe a "vibrating electron" in this context.
The summary is equivalent to an account of a baseball game written by someone who has never seen a ball, or a game, of any kind. It is depressing that "science journalism" scrapes along at a standard that is an order of magnitude below anything found in sports journalism, which is itself not exactly a paragon of insight and coherence.
The paper itself can be found here: http://arxiv.org/pdf/1408.5362...
It is a beautiful piece of work that really does open up new doors to precision measurement of beta spectra.
Blasphemy is a human right. Blasphemophobia kills.