ILC's High-Energy Collisions Require Accurate Energy Measurements

Jul 03, 2007
ILC's High-Energy Collisions Require Accurate Energy Measurements
University of California, Berkeley, student Erik Petigura (left) and Alexey Lyapin of University College London stand by components of the energy spectrometer in End Station A.

The International Linear Collider (ILC) collaboration proposes to crash electron and positron beams together with a total energy of 500 GeV (billion electron volts). The actual energy of each beam will vary slightly from one bunch of particles to the next, so just before the collision point, energy spectrometers will measure each bunch's exact energy.

"We need to be able to measure the beam energy with an accuracy of one part in 10,000 to establish the masses of the new particles we'll hopefully see," said Yury Kolomensky, associate professor of physics at the University of California-Berkeley.

Kolomensky and his collaborators (from SLAC, the University of California, Berkeley, and the University of Notre Dame in the U.S.; University College London, Royal Holloway College, and Cambridge University in the U.K.; DESY in Germany; and Dubna in Russia) have installed their prototype energy spectrometer on the beam line in End Station A. For most of July, a test beam of electrons will whiz down the beam line, letting Kolomensky and others test equipment under ILC-like conditions. The energy of the test beam is about ten times less than that of an ILC beam, but has the same bunch length and charge.

Existing spectrometers can't provide the required accuracy for a single bunch at a time. The prototype starts where most energy spectrometers do, with a set of magnets that deflect the beam. Beam position monitors, provided by SLAC and a group from University College London, measure the amount of deflection. The higher the beam's energy, the less the beam gets deflected. In End Station A, four magnets bend the beam about 5 millimeters horizontally over the course of the 20-meter-long energy spectrometer set-up.

In addition, the prototype has a way to very precisely and very accurately measure the magnetic field over the entire spectrometer during each pulse of the beam. 'Precisely' is like throwing darts that all land very close to one another; 'accurately' is all those darts hitting the bull's-eye. Collaborators from DESY and Dubna worked with the Magnetic Measurement Group at SLAC this past fall and winter to determine the magnetic fields at all positions along the beam trajectory through the spectrometer magnets.

After testing the components in March, researchers are now ready to run. "The goal is to have a demonstration of the technology that will ultimately go into the ILC design," Kolomensky said.

Source: by Heather Rock Woods, SLAC Today

Explore further: Tiny particles have big potential in debate over nuclear proliferation

add to favorites email to friend print save as pdf

Related Stories

Team pioneers strategy for creating new materials

Aug 29, 2014

Making something new is never easy. Scientists constantly theorize about new materials, but when the material is manufactured it doesn't always work as expected. To create a new strategy for designing materials, ...

EUV calibrations for satellite sensors

Aug 26, 2014

Thanks to precision calibration measurements recently performed at NIST, satellites may soon be looking at sunlight with new and improved vision.

A single diamond crystal does the job

Aug 25, 2014

( —X-ray absorption spectroscopy (XAS) is a technique used in many areas of science, from biology to materials science,that allows researchers to uncover information on a sample's molecular structure ...

Recommended for you

New method for non-invasive prostate cancer screening

2 hours ago

Cancer screening is a critical approach for preventing cancer deaths because cases caught early are often more treatable. But while there are already existing ways to screen for different types of cancer, ...

How bubble studies benefit science and engineering

3 hours ago

The image above shows a perfect bubble imploding in weightlessness. This bubble, and many like it, are produced by the researchers from the École Polytechnique Fédérale de Lausanne in Switzerland. What ...

Famous Feynman lectures put online with free access

4 hours ago

( —Back in the early sixties, physicist Richard Feynman gave a series of lectures on physics to first year students at Caltech—those lectures were subsequently put into print and made into text ...

Single laser stops molecular tumbling motion instantly

8 hours ago

In the quantum world, making the simple atom behave is one thing, but making the more complex molecule behave is another story. Now Northwestern University scientists have figured out an elegant way to stop a molecule from ...

User comments : 0