Antihydrogen detection in ALPHA

• Published in: Hyperfine interactions 2012-12, Vol.212 (1-3), p.91-99
• Main Authors: Hydomako, Richard, Andresen, Gorm Bruun, Ashkezari, Mohammad Dehghani, Baquero-Ruiz, Marcelo, Bertsche, William, Butler, Eoin, Bowe, Paul David, Cesar, Claudo Lenz, Chapman, Steve, Charlton, Michael, Fajans, Joel, Friesen, Tim, Fujiwara, Makoto C., Gill, David Russell, Hangst, Jeffrey Scott, Hardy, Walter Newbold, Hayano, Ryugo S., Hayden, Michael Edward, Humphries, Andrew James, Jonsell, Svante, Kurchaninov, Leonid, Madsen, Niels, Menary, Scott, Nolan, Paul, Olchanski, Konstantin, Olin, Arthur, Povilus, Alexander, Pusa, Petteri, Robicheaux, Francis, Sarid, Elazar, Silveira, Daniel Miranda, So, Chukman, Storey, James William, Thompson, Robert Ian, van der Werf, Dirk Peter, Wurtele, Jonathan Syrkin, Yamazaki, Yasunori
• Format: Article
• Language: English
• Subjects: Atomic; Condensed Matter Physics; Hadrons; Heavy Ions; Molecular; Nuclear Physics; Optical and Plasma Physics; Physics; Physics and Astronomy; Surfaces and Interfaces; Thin Films
• ISSN: 0304-3843; 1572-9540
• DOI: 10.1007/s10751-011-0456-8

The ALPHA project is an international collaboration, based at CERN, with the experimental goal of performing precision spectroscopic measurements on antihydrogen. As part of this endeavor, the ALPHA experiment includes a silicon tracking detector. This detector consists of a three-layer array of silicon modules surrounding the antihydrogen trapping region of the ALPHA apparatus. Using this device, the antihydrogen annihilation position can be determined with a spatial resolution of better than 5 mm. Knowledge of the annihilation distribution was a critical component in the recently successful antihydrogen trapping effort. This paper will describe the methods used to reconstruct annihilation events in the ALPHA detector. Particular attention will be given to the description of the background rejection criteria.