Catch and Release: Fishing for Barium Ions

Dec 05, 2006
Catch and Release: Fishing for Barium Ions
Peter Rowson examines a vacuum system containing a liquid xenon cell, which was used to test cryogenically cooled "fishing poles." Credit: Stanford Linear Accelerator Center

How do you identify the rare thing you're looking for in a vast sea? Go fishing.

Researchers on the Enriched Xenon Observatory (EXO) project, including a group from SLAC, are currently developing ways to catch barium ion "fish" from inside a multi-ton vessel of liquid. They then remove the ions from the liquid and release them from the fishing pole so they can be identified as barium.

A barium-136 ion is the unmistakable sign that somewhere in the sea of xenon-136, a xenon atom underwent radioactive decay. If the two electrons released from that decay have a particular energy, scientists will have hooked the proof that neutrinos are their own anti-particle—an exciting but unproven idea. The observation will also give EXO a way to measure the scanty mass of neutrinos.

The radioactive decay normally emits two neutrinos as well, yet ironically, finding a decay with no neutrinos is what will tell scientists that neutrinos and anti-neutrinos are the same thing. In "neutrinoless double beta decay," the electrons carry all the decay energy otherwise shared with the neutrinos.

Fishing for barium will help the experiment separate the real fish from spurious fish—electrons in the right energy range that come from other sources, such as natural radioactivity and cosmic rays.

After a xenon decay, "the barium ion is sitting there. It hardly moves, so you have to go fish it out," said EXO physicist Peter Rowson.

SLAC has already demonstrated that an electrostatic probe—a small metal fishing pole—can pick up ions from xenon liquid. The probe's electric field attracts positively charged ions. R&D now centers on how to unhook the barium ion from the probe, so it can be identified by a laser system developed by Stanford University, which leads the EXO collaboration. The SLAC group has developed one approach, a cryogenically cooled probe.

"When the probe is dipped in the liquid, xenon ice forms and the ion gets trapped on ice. We pull the probe out, let it thaw and release the ion," said Rowson.

Just don't try it on real fish.

Source: by Heather Rock Woods, Stanford Linear Accelerator Center

Explore further: Neutron tomography technique reveals phase fractions of crystalline materials in 3-dimensions

add to favorites email to friend print save as pdf

Related Stories

Big chill sets in as RHIC physics heats up

Feb 04, 2014

If you think it's been cold outside this winter, that's nothing compared to the deep freeze setting in at the Relativistic Heavy Ion Collider (RHIC), the early-universe-recreating "atom smasher" at the U.S. ...

Shaking the electron has strengthened quantum mechanics

Aug 24, 2012

Decays of atomic nuclei are potential sources of information on fundamental phenomena occurring in the quantum world. Unfortunately, it is a rather difficult task to model such processes. However, NCBJ physicists ...

Tin-100 produced in key nuclear physics experiment

Jun 20, 2012

A few minutes after the Big Bang the universe contained no other elements than hydrogen and helium. Physicists of the Technische Universitaet Muenchen and the Helmholtz Center for Heavy Ion Research have now ...

Antarctic "Telescopes" Look for Cosmic Rays

Feb 08, 2005

Working in the harsh conditions of Antarctica, Maryland researchers are creating new ways of detecting cosmic rays, high energy particles that bombard the Earth from beyond our solar system.

Recommended for you

50-foot-wide Muon g-2 electromagnet installed at Fermilab

1 hour ago

One year ago, the 50-foot-wide Muon g-2 electromagnet arrived at the U.S. Department of Energy's Fermi National Accelerator Laboratory in Illinois after traveling 3,200 miles over land and sea from Long Island, ...

Spin-based electronics: New material successfully tested

Jul 30, 2014

Spintronics is an emerging field of electronics, where devices work by manipulating the spin of electrons rather than the current generated by their motion. This field can offer significant advantages to computer technology. ...

User comments : 0