The group's method for directly measuring the magnetic moment of a particle is based on the fact that a proton in a Penning trap
aligns its spin with the trap's magnetic field.
Called a Penning trap
, it operates at the temperature of 4 degrees Kelvin (452.
Stefan Ulmer, a particle physicist at RIKEN in Wako, Japan, and colleagues analyzed antiprotons and negative hydrogen ions (a proton plus two electrons) one by one inside an instrument called a Penning trap.
They found that as particles circled inside the Penning trap, gravity acted on protons and antiprotons with the same strength, just as Einstein's theory predicts.
Developed by Biercuk and colleagues, the device consists of a few dozen beryllium ions in a device called a Penning trap
The most-advanced instrument for high-accuracy mass determinations is the Penning trap
using the fundamental techniques of cooling and storing.
Ulmer and his team used a device called a Penning trap
to improve on previous magnetic moment measurements for the proton.
To make the mass measurement, the team used a device called a Penning trap
, which employs electric and magnetic fields to confine atoms.
The so-called Paul trap and its cousin, the Penning trap
, play an important role in modern spectroscopy.
Such a crystal, confined in a Penning trap
with its rotation locked to a rotating electric field, has potential applications in atomic frequency standards and quantum logic.
One experiment aimed at doing that at the CERN laboratory in Geneva, Switzerland, has managed to capture antiprotons in a device called a Penning trap
and hold them for periods of up to 10 minutes.
In order to make their measurements, the researchers used protons generated by CERN's antiproton decelerator and placed them in Penning traps
, which use a strong magnetic field to trap particles.