Tag Archives: CERN

First Ever Antimatter Spectroscopy in ALPHA-2

Peter Lobner

ALPHA-2 is a device at the European particle physics laboratory at CERN, in Meyrin, Switzerland used for collecting and analyzing antimatter, or more specifically, antihydrogen.  A common hydrogen atom is composed of an electron and proton.  In contrast, an  antihydrogen atom is made up of a positron bound to an antiproton.

Screen Shot 2016-12-22 at 4.19.01 PMSource: CERN

The ALPHA-2 project homepage is at the following link:


On 16 December 2016, the ALPHA-2 team reported the first ever optical spectroscopic observation of the 1S-2S (ground state – 1st excited state) transition of antihydrogen that had been trapped and excited by a laser.

“This is the first time a spectral line has been observed in antimatter. ……..This first result implies that the 1S-2S transition in hydrogen and antihydrogen are not too different, and the next steps are to measure the transition’s lineshape and increase the precision of the measurement.”

In the ALPHA-2 online news article, “Observation of the 1S-2S Transition in Trapped Antihydrogen Published in Nature,” you will find two short videos explaining how this experiment was conducted:

  • Antihydrogen formation and 1S-2S excitation in ALPHA
  • ALPHA first ever optical spectroscopy of a pure anti atom

These videos describe the process for creating antihydrogen within a magnetic trap (octupole & mirror coils) containing positrons and antiprotons. Selected screenshots from the first video are reproduced below to illustrate the process of creating and exciting antihydrogen and measuring the results.

Alpha2 mirror trap

The potentials along the trap are manipulated to allow the initially separated positron and antiproton populations to combine, interact and form antihydrogen.

Combining positron & antiproton 1Combining positron & antiproton 2Combining positron & antiproton 3

If the magnetic trap is turned off, the antihydrogen atoms will drift into the inner wall of the device and immediately be annihilated, releasing pions that are detected by the “annihilation detectors” surrounding the magnetic trap. This 3-layer detector provides a means for counting antihydrogen atoms.

Detecting antihydrogen

A tuned laser is used to excite the antihydrogen atoms in the magnetic trap from the 1S (ground) state to the 2S (first excited) state. The interaction of the laser with the antihydrogen atoms is determined by counting the number of free antiprotons annihilating after photo ionization (an excited antihydrogen atom loses its positron) and counting all remaining antihydrogen atoms. Two cases were investigated: (1) laser tuned for resonance of the 1S-2S transition, and (2) laser detuned, not at resonance frequency. The observed differences between these two cases confirmed that, “the on-resonance laser light is interacting with the antihydrogen atoms via their 1S-2S transition.”

Exciting antihydrogen

The ALPHA-2 team reported that the accuracy of the current antihydrogen measurement of the 1S-2S transition is about “a few parts in 10 billion” (1010). In comparison, this transition in common hydrogen has been measured to an accuracy of “a few parts in a thousand trillion” (1015).

For more information, see the 19 December 2016 article by Adrian Cho, “Deep probe of antimatter puts Einstein’s special relativity to the test,” which is posted on the Sciencemag.org website at the following link:


CERN Announces Large Hadron Collider (LHC) Return to Operation

Peter Lobner

After a two-year shutdown for modifications that are expected to nearly double the maximum energy of LHC to 13 TeV, CERN has completed a long re-test process and restored LHC to operation. You can read about the restart process at the following link:


image   Source: CERN

Re-start was delayed by an intermittent short circuit that had to be resolved after the superconducting machine had already been cooled down. Maintenance and repair is time-consuming when a superconducting component or system is involved, since the equipment must be warmed up before it can be serviced, and then cooled down again to 1.9 degrees Celsius before LHC operation can resume.

With the LHC back in operation, the search for more Higgs Bosons and signs of supersymmetry continues. Read more about LHC operations at the following link:


You also might want to review Maria Spiropulo’s 27 August 2014 Lyncean presentation: “The Future of the Higgs Boson.” You can find this presentation in the Past Meetings section of this Lyncean website.

The World’s Oldest dot.com Address is 30 Years Old

Peter Lobner

We’ve come a long way since the first Internet dot-com address, symbolics.com, was registered on 15 March 1985 by Massachusetts-based computer company Symbolics, which  was one of the original makers of computer workstations. The Lisp computer language that Symbolics developed eventually faded in popularity. Symbolics  filed for bankruptcy in 1993, but the company and its symbolics.com website continue to exist today. Read more at the following link:


It wasn’t until 1989 that the basis for the world-wide web was created by British computer scientist Tim Berners-Lee in a proposal that originally was meant to create a more effective  communication system at the European Organization for Nuclear Research (CERN). Berners-Lee and Belgian computer scientist Robert Cailliau proposed in 1990 to use hypertext “to link and access information of various kinds as a web of nodes in which the user can browse at will.” Berners-Lee built and tested the first website around 20 December 1990 and reported about the project on the newsgroup alt.hypertext on 7 August 1991.

First www site

You can read more about Berners-Lee’s first website, and several other early web sites, at the following link: