Antiproton Accumulator
The Antiproton Accumulator (AA) was an infrastructure connected to the
The concept of the project was developed and promoted by C. Rubbia, for which he received the Nobel prize in 1984.[5] He shared the prize with Simon van der Meer, whose invention of the method of stochastic cooling made large scale production of antiprotons possible for the first time.
Operation
Antiprotons were produced by directing an intense proton beam at a momentum of 26 GeV/c from the
The dense core of antiprotons was then ejected from the AA, and accelerated to 26 GeV/c, using the PS. Three antiproton bunches were consecutively transferred to the SppS, every 2.4 s.[7] Just before the antiproton transfer, the PS would already have accelerated and transferred three proton bunches circulating the opposite direction to the antiprotons. When three bunches of antiprotons and three bunches of protons have filled the SppS, the bunches were accelerated to 315 GeV, and the beams were circulated for hours. During this time the AA continued to accumulate, to be ready for the next day's transfer.[7]
Antimatter experiments
Extra Low Energy Antiproton ring (ELENA) | Decelerates antiprotons received from AD |
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From the beginning of the project, the potential of physics with low-energy antiprotons was recognized. A Low Energy Antiproton Ring (LEAR) was built and received antiprotons from the AA from 1983 on, for deceleration to as low as 100 MeV/c.[8] The first artificially created antimatter, in the form of anti-Hydrogen, was created in a trapping experiment at LEAR in 1995. However, the first client for antiprotons from the AA had been the Intersecting Storage Rings
Upgrade of the Antiproton Accumulation system
To satisfy the need for more antiprotons, the ACOL (Antiproton COLlector) project was conceived in 1983[9] and implemented in 1986 and 1987. The antiproton production (target and target area) was upgraded; the Antiproton Collector (AC), with an acceptance in transverse and longitudinal phase-space much larger than that of the AA, was built tightly around the AA; and the AA was consequently modified. The AA accumulation rate, previously typically 1011 antiprotons per day, was thus raised by an order of magnitude, to typically 1012.
AC and AA together were referred to as the Antiproton Accumulation Complex (AAC).[10][11] The AAC was one of the most highly automated complex of accelerators of its time.[12]
After the last run of the SppS, in 1991, LEAR remained the sole client of the AAC, and a simpler way to serve low-energy physics was sought. LEAR was converted to become the Low Energy Ion Ring (LEIR), the AA was dismantled, and the AC was converted to become the Antiproton Decelerator (AD).
See also
- UA1 experiment
- UA2 experiment
- Stochastic cooling
- W and Z bosons
- Antiproton Collector
- Super Proton–Antiproton Synchrotron
References
- S2CID 33805929.
- S2CID 39013232.
- ISSN 0370-1573.
- )
- ^ "Press Release: The 1984 Nobel Prize in Physics". Nobelprize.org. 17 October 1984. Retrieved 24 July 2017.
- ISSN 0018-9499.
- ^ a b c d Evans, Lyndon; Jones, Eifionydd; Koziol, Heribert (1989). "The CERN ppbar Collider". In Altarelli, G.; Di Lella, Luigi (eds.). Proton-Antiproton Collider Physics. Advanced Series on Directions in High Energy Physics. Vol. 4. World Scientific Publishing.
- ISSN 0370-1573.
- ^ Wilson, Edmund J. N., ed. (1983). Design study of an antiproton collector for the antiproton accumulator (ACOL) (PDF). CERN.
- ISBN 9789971502560.
- ^ Carron, G.; et al. (1993). "The CERN antiproton accumulator complex (AAC) : current status and operation for the nineties" (PDF). In Rossbach, J. (ed.). 15th International Conference on High-Energy Accelerators. World Scientific. pp. 106–108.
- ISSN 0168-9002.