Antiproton Decelerator

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CERN Complex
CERN accelerator complex 2022.png
Current particle and nuclear facilities
LHC Accelerates protons and heavy ions
LEIR Accelerates ions
SPS Accelerates protons and ions
PSB Accelerates protons
PS Accelerates protons or ions
Linac 3 Injects heavy ions into LEIR
Linac4 Accelerates ions
AD Decelerates antiprotons
ELENA Decelerates antiprotons
ISOLDE Produces radioactive ion beams
MEDICIS Produces isotopes for medical purposes

The Antiproton Decelerator (AD) is a storage ring at the CERN laboratory near Geneva. [1] It was built from the Antiproton Collector (AC) to be a successor to the Low Energy Antiproton Ring (LEAR) and started operation in the year 2000. Antiprotons are created by impinging a proton beam from the Proton Synchrotron on a iridium target. The AD decelerates the resultant antiprotons to an energy of 5.3 MeV, which are then ejected to one of several connected experiments.

Contents

The major goals of experiments at AD are to spectroscopically observe the antihydrogen and to study the effects of gravity on antimatter. Though each experiment at AD has varied aims ranging from testing antimatter for cancer therapy to CPT symmetry and antigravity research.

History

Antimatter facilities
Low Energy Antiproton Ring (1982–1996)
Antiproton Accumulator Antiproton production
Antiproton Collector Decelerated and stored antiprotons
Antimatter Factory (2000–present)
Antiproton Decelerator (AD) Decelerates antiprotons
Extra Low Energy Antiproton ring (ELENA) Decelerates antiprotons received from AD

From 1982 to 1996, CERN operated the Low Energy Antiproton Ring (LEAR), through which several experiments with slow-moving antiprotons were carried out. During the end stages of LEAR, the physics community involved in those antimatter experiments wanted to continue their studies with the slow antiprotons. The motivation to build the AD grew out of the Antihydrogen Workshop held in Munich in 1992. [2] [3] This idea was carried forward quickly and AD's feasibility study was completed by 1995. [4]

In 1996, the CERN Council asked the Proton Synchrotron (PS) division to look into the possibility of generating slow antiproton beams. The PS division prepared a design study in 1996 with the solution to use the antiproton collector (AC), and transform it into a single Antiproton Decelerator Machine. The AD was approved in February 1997. [5] [6]

AC modification, AD installation, and commissioning process were carried out in the next three years. By the end of 1999, the AC ring was modified into a decelerator and cooling system- forming the Antiproton Decelerator. [3] [7]

Decelerator

AD's oval-shaped perimeter has four straight sections where the deceleration and cooling systems are placed. There are several dipole and quadrupole magnets in these sections to avoid beam dispersion. Antiprotons are cooled and decelerated in a single 100-second cycle in the AD synchrotron. [3]

Production of antiprotons

AD requires about protons of momentum 26 GeV/c to produce antiprotons per minute. The high-energy protons coming from the proton synchrotron are made to collide with a thin, highly dense rod of iridium metal of 3-mm diameter and 55 cm in length. [3] The iridium rod embedded in graphite and enclosed by a sealed water-cooled titanium case remains intact. But the collisions create a lot of energetic particles, including the antiprotons. A magnetic bi-conical aluminum horn-type lens collects the antiprotons emerging from the target. This collector takes in the 3.5 GeV/c antiprotons, and they are separated from other particles using deflection through electromagnetic forces. [3] [4]

CERN AD with the ALPHA, ASACUSA and ATRAP experiments. Experimental area at CERNs Antiproton Decelerator (AD) Hall.jpg
CERN AD with the ALPHA, ASACUSA and ATRAP experiments.

Deceleration, accumulation and cooling down

Radio frequency (RF) systems decelerate and bunch the cooled antiprotons at 3.5 GeV/c. Numerous magnets inside focus the randomly moving antiprotons into a collimated beam and bend the beam. Simultaneously the electric fields further decelerate them. [1] [4]

Stochastic cooling and electron cooling stages designed inside the AD decrease the energy of beams as well as limit the antiproton beam from any significant distortions. Stochastic cooling is applied for antiprotons at 3.5 GeV/c and then at 2 GeV/c, followed by electron cooling at 0.3 GeV/c and at 0.1 GeV/c. The final output beam has a momentum of 0.1 GeV/c (kinetic energy equal to 5.3 MeV). These antiprotons move with the speed of about one-tenth that of light. [1] [3] [7]

But the experiments need much lower energy beams (3 to 5 KeV). So the antiprotons are again decelerated to ~5 KeV, using the degrader foils. This step accounts for the loss of 99.9% of antiprotons. The collected antiprotons are then temporarily stored in the Penning traps; before being fed into the several AD experiments. The Penning traps can also form antihydrogen by combining antiprotons with the positrons. [3] [7]

ELENA

ELENA ring CERN Antimatter factory - Elena experiment.jpg
ELENA ring

ELENA (Extra Low ENergy Antiproton) is a 30 m hexagonal storage ring situated inside the AD complex. [8] [9] It is designed to further decelerate the antiproton beam to an energy of 0.1 MeV for more precise measurements. [10] [11] The first beam circulated ELENA on 18 November 2016. [12] GBAR was the first experiment to use a beam from ELENA, with the rest of the AD experiments to follow suit after LS2 when beam transfer lines from ELENA will have been laid to all the experiments using the facility. [13]

AD experiments

AD experiments
ExperimentCodenameSpokespersonTitleProposedApprovedBeganCompletedLinkWebsite
AD-1 ATHENA Alberto Rotondi Antihydrogen production and precision experiments20 Oct 199612 Jun 19976 Apr 200116 Nov 2004 INSPIRE
Grey Book 		–
AD-2 ATRAP Gerald Gabrielse Cold antihydrogen for precise laser spectroscopy25 Mar 199712 Jun 199712 Feb 2002Running INSPIRE
Grey Book 		Website Archived 2 August 2016 at the Wayback Machine
AD-3 ASACUSA Eberhard Widmann and Masaki HoriAtomic spectroscopy and collisions using slow antiprotons7 Oct 199720 Nov 199712 Feb 2002Running INSPIRE
Grey Book 		Website Archived 17 January 2016 at the Wayback Machine
AD-4 ACE Michael Holzscheiter Relative biological effectiveness and peripheral damage of antiproton annihilation21 Aug 20026 Feb 200326 Jan 200424 Sep 2013 INSPIRE
Grey Book 		Website
AD-5 ALPHA Jeffrey Hangst Antihydrogen laser physics apparatus21 Sep 20042 Jun 200518 Apr 2008Running INSPIRE
Grey Book 		Website
AD-6 AEgIS Ruggero Caravita Antimatter Experiment gravity Interferometry Spectroscopy8 Jun 20075 Dec 200828 Sep 2014Running INSPIRE
Grey Book 		Website
AD-7 GBAR Patrice Perez Gravitational Behaviour of Anti-Hydrogen at Rest30 Sep 201130 May 201203 Oct 2012Preparation INSPIRE
Grey Book 		Website Archived 20 August 2016 at the Wayback Machine
AD-8 BASE Stefan Ulmer Baryon Antibaryon Symmetry ExperimentApr 20135 Jun 20139 Sep 2014Running INSPIRE
Grey Book 		Website
AD-9 PUMA Alexandre Obertelli antiProton Unstable Matter Annihilation29 Sep 201917 Mar 2021N/APreparation INSPIRE
Grey Book 		–

ATHENA

ATHENA, AD-1 experiment, was an antimatter research project that took place at the Antiproton Decelerator. In August 2002, it was the first experiment to produce 50,000 low-energy antihydrogen atoms, as reported in Nature . [14] [15] In 2005, ATHENA was disbanded and many of the former members worked on the subsequent ALPHA experiment.

ATRAP

The Antihydrogen Trap (ATRAP) collaboration, responsible for the AD-2 experiment, is a continuation of the TRAP collaboration, which started taking data for the PS196 experiment in 1985. [16] [17] The TRAP experiment (PS196) pioneered cold antiprotons, cold positrons, and first made the ingredients of cold antihydrogen to interact. Later ATRAP members pioneered accurate hydrogen spectroscopy and observed the first hot antihydrogen atoms.

ASACUSA

Atomic Spectroscopy and Collisions Using Slow Antiprotons (ASACUSA), AD-3, is an experiment testing for CPT-symmetry by laser spectroscopy of antiprotonic helium and microwave spectroscopy of the hyperfine structure of antihydrogen. It compares matter and antimatter using antihydrogen and antiprotonic helium and looks into matter-antimatter collisions. [18] [19] It also measures atomic and nuclear cross-sections of antiprotons on various targets at extremely low energies. [20]

ACE

Members of ACE collaboration at experimental setup Ace22.jpg
Members of ACE collaboration at experimental setup

The Antiproton Cell Experiment (ACE), AD-4, started in 2003. It aims to assess fully the effectiveness and suitability of antiprotons for cancer therapy. The results showed that antiprotons required to break down the tumor cells were four times less than the number of protons required. The effect on healthy tissues due to antiprotons was significantly less. Although the experiment ended in 2013, further research and validation still continue, owing to the long procedures of bringing in novel medical treatments. [21] [22]

ALPHA

ALPHA experiment CERN Antimatter factory - Alpha experiment.jpg
ALPHA experiment

The Antihydrogen Laser Physics Apparatus (ALPHA), the AD-5 experiment, is designed to trap neutral antihydrogen in a magnetic trap, and conduct experiments on them. The ultimate goal of this endeavour is to test CPT symmetry through comparison of the atomic spectra of hydrogen and antihydrogen (see hydrogen spectral series). [23] The ALPHA collaboration consists of some former members of the ATHENA collaboration (the first group to produce cold antihydrogen, in 2002), as well as a number of new members.

AEgIS

AEgIS, Antimatter Experiment: gravity, Interferometry, Spectroscopy, AD-6, is an experiment at the Antiproton Decelerator. AEgIS would attempt to determine if gravity affects antimatter in the same way it affects normal matter by testing its effect on an antihydrogen beam. The first phase of the experiment created antihydrogen using the charge exchange reaction between antiprotons from the Antiproton Decelerator (AD) and positronium, producing a pulse of antihydrogen atoms. These atoms are sent through a series of diffraction gratings, ultimately hitting a surface and thus annihilating. The points where the antihydrogen annihilates are measured with a precise detector. Areas behind the gratings are shadowed, while those behind the slits are not. The annihilation points reproduce a periodic pattern of light and shadowed areas. Using this pattern, it can be measured how many atoms of different velocities are vertically displaced due to gravity during n their horizontal flight. Therefore, the Earth's gravitational force on antihydrogen can be determined. [24]

GBAR

GBAR (Gravitational Behaviour of Anti hydrogen at Rest) experiment CERN Antimatter factory - GBAR experiment.jpg
GBAR (Gravitational Behaviour of Anti hydrogen at Rest) experiment

GBAR (Gravitational Behaviour of Anti hydrogen at Rest), AD-7 experiment, is a multinational collaboration at the Antiproton Decelerator of CERN. The GBAR project aims to measure the free-fall acceleration of ultra-cold neutral anti-hydrogen atoms in the terrestrial gravitational field. By measuring the free fall acceleration of anti-hydrogen and comparing it with acceleration of normal hydrogen, GBAR is testing the equivalence principle proposed by Albert Einstein. The equivalence principle says that the gravitational force on a particle is independent of its internal structure and composition. [25]

BASE

BASE (Baryon Antibaryon Symmetry Experiment), AD-8, is a multinational collaboration at the Antiproton Decelerator of CERN.

The goal of the Japanese/German BASE collaboration [26] are high-precision investigations of the fundamental properties of the antiproton, namely the charge-to-mass ratio and the magnetic moment. The single antiprotons are stored in an advanced Penning trap system, which has a double-trap system at its core, for high precision frequency measurements and for single particle spin flip spectroscopy. By measuring the spin flip rate as a function of the frequency of an externally applied magnetic-drive, a resonance curve is obtained. Together with a measurement of the cyclotron frequency, the magnetic moment is extracted.

PUMA

The PUMA (antiProton Unstable Matter Annihilation experiment), AD-9, aims to look into the quantum interactions and annihilation processes between the antiprotons and the exotic slow-moving nuclei. PUMA's experimental goals require about one billion trapped antiprotons made by AD and ELENA to be transported to the ISOLDE-nuclear physics facility at CERN, which will supply the exotic nuclei. [27] Antimatter has never been transported out of the AD facility before. Designing and building a trap for this transportation is the most challenging aspect for the PUMA collaboration. [28] [29] [27]

See also

Related Research Articles

<span class="mw-page-title-main">Antimatter</span> Material composed of antiparticles of the corresponding particles of ordinary matter

In modern physics, antimatter is defined as matter composed of the antiparticles of the corresponding particles in "ordinary" matter, and can be thought of as matter with reversed charge, parity, and time, known as CPT reversal. Antimatter occurs in natural processes like cosmic ray collisions and some types of radioactive decay, but only a tiny fraction of these have successfully been bound together in experiments to form antiatoms. Minuscule numbers of antiparticles can be generated at particle accelerators; however, total artificial production has been only a few nanograms. No macroscopic amount of antimatter has ever been assembled due to the extreme cost and difficulty of production and handling. Nonetheless, antimatter is an essential component of widely available applications related to beta decay, such as positron emission tomography, radiation therapy, and industrial imaging.

<span class="mw-page-title-main">Antihydrogen</span> Exotic particle made of an antiproton and positron

Antihydrogen is the antimatter counterpart of hydrogen. Whereas the common hydrogen atom is composed of an electron and proton, the antihydrogen atom is made up of a positron and antiproton. Scientists hope that studying antihydrogen may shed light on the question of why there is more matter than antimatter in the observable universe, known as the baryon asymmetry problem. Antihydrogen is produced artificially in particle accelerators.

<span class="mw-page-title-main">Antiproton</span> Subatomic particle

The antiproton,
p
, is the antiparticle of the proton. Antiprotons are stable, but they are typically short-lived, since any collision with a proton will cause both particles to be annihilated in a burst of energy.

ATHENA, also known as the AD-1 experiment, was an antimatter research project at the Antiproton Decelerator at CERN, Geneva. In August 2002, it was the first experiment to produce 50,000 low-energy antihydrogen atoms, as reported in Nature. In 2005, ATHENA was disbanded and many of the former members of the research team worked on the subsequent ALPHA experiment and AEgIS experiment.

<span class="mw-page-title-main">Protonium</span> Bound state of a proton and antiprotron

Protonium, also known as antiprotonic hydrogen, is a type of exotic atom in which a proton and an antiproton are bound to each other.

The Antihydrogen Trap (ATRAP) collaboration at the Antiproton Decelerator facility at CERN, Geneva, was responsible for the AD-2 experiment. It was a continuation of the TRAP collaboration, which started taking data for the TRAP experiment in 1985. The TRAP experiment pioneered cold antiprotons, cold positrons, and first made the ingredients of cold antihydrogen to interact. Later ATRAP members pioneered accurate hydrogen spectroscopy and observed the first hot antihydrogen atoms.

<span class="mw-page-title-main">Antiprotonic helium</span> Exotic matter with an antiproton in place of an electron

Antiprotonic helium is a three-body atom composed of an antiproton and an electron orbiting around a helium nucleus. It is thus made partly of matter, and partly of antimatter. The atom is electrically neutral, since an electron and an antiproton each have a charge of −1 e, whereas a helium nucleus has a charge of +2 e. It has the longest lifetime of any experimentally produced matter–antimatter bound state.

<span class="mw-page-title-main">Gravitational interaction of antimatter</span> Theory of gravity on antimatter

The gravitational interaction of antimatter with matter or antimatter has been observed by physicists. As was the consensus among physicists previously, it was experimentally confirmed that gravity attracts both matter and antimatter at the same rate within experimental error.

<span class="mw-page-title-main">Low Energy Antiproton Ring</span> Former CERN infrastructure

The Low Energy Anti-Proton Ring (LEAR) was a particle accelerator at CERN which operated from 1982 until 1996. The ring was designed to decelerate and store antiprotons, to study the properties of antimatter and to create atoms of antihydrogen. Antiprotons for the ring were created by the CERN Proton Synchrotron via the Antiproton Collector and the Antiproton Accumulator (AA). The creation of at least nine atoms of antihydrogen were confirmed by the PS210 experiment in 1995.

Atomic Spectroscopy and Collisions Using Slow Antiprotons (ASACUSA), AD-3, is an experiment at the Antiproton Decelerator (AD) at CERN. The experiment was proposed in 1997, started collecting data in 2002 by using the antiprotons beams from the AD, and will continue in future under the AD and ELENA decelerator facility.

High-precision experiments could reveal small previously unseen differences between the behavior of matter and antimatter. This prospect is appealing to physicists because it may show that nature is not Lorentz symmetric.

<span class="mw-page-title-main">Antiproton Collector</span> CERN infrastructure

The Antiproton Collector (AC) was part of the antiparticle factory at CERN designed to decelerate and store antimatter, to study the properties of antimatter and to create atoms of antihydrogen. It was built in 1986 around the existing Antiproton Accumulator (AA) to improve the antiproton production by a factor of 10. Together, the Antiproton Collector and the Antiproton Accumulator formed the so-called Antiproton Accumulator Complex (AAC).

<span class="mw-page-title-main">Antiproton Accumulator</span> Part of the CERN proton-antiproton collider

The Antiproton Accumulator (AA) was an infrastructure connected to the Proton–Antiproton Collider – a modification of the Super Proton Synchrotron (SPS) – at CERN. The AA was built in 1979 and 1980, for the production and accumulation of antiprotons. In the SppS the antiprotons were made to collide with protons, achieving collisions at a center of mass energy of app. 540 GeV. Several experiments recorded data from the collisions, most notably the UA1 and UA2 experiment, where the W and Z bosons were discovered in 1983.

<span class="mw-page-title-main">ALPHA experiment</span> Antimatter gravitation experiment

The Antihydrogen Laser Physics Apparatus (ALPHA), also known as AD-5, is an experiment at CERN's Antiproton Decelerator, designed to trap antihydrogen in a magnetic trap in order to study its atomic spectra. The ultimate goal of the experiment is to test CPT symmetry through comparing the respective spectra of hydrogen and antihydrogen. Scientists taking part in ALPHA include former members of the ATHENA experiment (AD-1), the first to produce cold antihydrogen in 2002.

AEgIS, AD-6, is an experiment at the Antiproton Decelerator facility at CERN. Its primary goal is to measure directly the effect of Earth's gravitational field on antihydrogen atoms with significant precision. Indirect bounds that assume the validity of, for example, the universality of free fall, the Weak Equivalence Principle or CPT symmetry also in the case of antimatter constrain an anomalous gravitational behavior to a level where only precision measurements can provide answers. Vice versa, antimatter experiments with sufficient precision are essential to validate these fundamental assumptions. AEgIS was originally proposed in 2007. Construction of the main apparatus was completed in 2012. Since 2014, two laser systems with tunable wavelengths and synchronized to the nanosecond for specific atomic excitation have been successfully commissioned.

<span class="mw-page-title-main">GBAR experiment</span> Experiment at the Antiproton Decelerator

GBAR, AD-7 experiment, is a multinational collaboration at the Antiproton Decelerator of CERN.

<span class="mw-page-title-main">Jeffrey Hangst</span> Experimental particle physicist

Jeffrey Scott Hangst is an experimental particle physicist at Aarhus University, Denmark, and founder and spokesperson of the ALPHA collaboration at the Antiproton Decelerator (AD) at CERN, Geneva. He was also one of the founding members and the Physics Coordinator of the ATHENA collaboration at the AD facility.

<span class="mw-page-title-main">Stefan Ulmer (physicist)</span> Particle physicist

Stefan Ulmer is a particle physicist, professor of Physics at Heinrich Heine University Düsseldorf and chief scientist at the Ulmer Fundamental Symmetries Laboratory, RIKEN, Tokyo. He is the founder and the spokesperson of the BASE experiment (AD-8) at the Antiproton Decelerator facility at CERN, Geneva. Stefan Ulmer is well known for his contributions to improving Penning trap techniques and precision measurements on antimatter. He is the first person to observe spin transitions with a single trapped proton as well as single spin transitions with a single trapped antiproton, a significant achievement towards a precision measurement of the antiproton magnetic moment.

Extra Low ENergy Antiproton ring (ELENA) is a 30 m hexagonal storage ring that decelerates antiproton beams and delivers it to different AD experiments. It is situated inside the Antiproton Decelerator (AD) complex at CERN, Geneva. It is designed to further decelerate the antiproton beam coming from the Antiproton decelerator to an energy of 0.1 MeV for more precise measurements. The first beam circulated ELENA on 18 November 2016. The ring is expected to be fully operational by the end of the Long Shutdown 2 (LS2) in 2021.

<span class="mw-page-title-main">PUMA experiment</span> Particle physics experiment at CERN

The PUMA AD-9 experiment, at the Antiproton decelerator (AD) facility at CERN, Geneva, aims to look into the quantum interactions and annihilation processes between the antiprotons and the exotic slow-moving nuclei. PUMA's experimental goals require about one billion trapped antiprotons made by AD and ELENA to be transported to the ISOLDE-nuclear physics facility at CERN, which will supply the exotic nuclei. Antimatter has never been transported out of the AD facility before. Designing and building a trap for this transportation is the most challenging aspect for the PUMA collaboration.

References

  1. 1 2 3 "The Antiproton Decelerator – CERN" . Retrieved 21 December 2016.
  2. ↑ "Antihydrogen Workshop, Munich, Germany, July 30–31, 1992". Hyperfine Interact. 76 (1993) 1, pp.1–397. Springer. 1993. Retrieved 6 July 2021.
  3. 1 2 3 4 5 6 7 Baird, S. A.; Berlin, D.; Boillot, J.; Bosser, Jacques; Brouet, M.; Buttkus, J.; Caspers, Friedhelm; Chohan, V.; Dekkers, Daniel (1996). Design study of the antiproton decelerator: AD. doi:10.17181/cern.knxm.aykr.
  4. 1 2 3 Autin, Bruno; Baird, S. A.; Berlin, D.; Boillot, J.; Bosser, Jacques; Brouet, M.; Caspers, Friedhelm; Chanel, M.; Chohan, V. (1995). The antiproton decelerator (AD), a simplified antiproton source (feasibility study). doi:10.17181/cern.0w6p.8onp.
  5. ↑ CERN. Geneva. Research Board; CERN. Geneva. Research Board, eds. (1997). Minutes of the 130th Meeting of the Research Board held on Thursday 6 February, 1997. CERN-DG-RB-Minutes.
  6. ↑ "The Low Energy Antiproton Ring". CERN. Retrieved 6 July 2021.
  7. 1 2 3 Hémery, J.Y.; Maury, S. (9 August 1999). "The Antiproton Decelerator: Overview". Nuclear Physics A. 655 (1–2): c345 –c352. Bibcode:1999NuPhA.655..345H. doi:10.1016/S0375-9474(99)00223-7. ISSN   0375-9474.
  8. ↑ "ELENA – Home". Archived from the original on 3 November 2013. Retrieved 28 November 2016.
  9. ↑ Oelert, W. (2015). "The ELENA Project at CERN". Acta Physica Polonica B . 46 (1): 181. arXiv: 1501.05728 . Bibcode:2015AcPPB..46..181O. doi:10.5506/APhysPolB.46.181. S2CID   119270123.
  10. ↑ Jorgensen, L V; Nosych, A; Sanchez-Quesada, J; Harasimowicz, J; LeGodec, G; Angoletta, M E; Kuchler, D; Zickler, T; Eriksson, T; Capatina, O; Dobers, T (2014). Extra Low ENergy Antiproton (ELENA) ring and its Transfer Lines: Design Report. CERN Yellow Reports: Monographs. doi:10.5170/CERN-2014-002. ISBN   9789290834007.
  11. ↑ Madsen, N. (2018). "Antiproton physics in the ELENA era". Phil. Trans. R. Soc. A. 376 (2116): 20170278. Bibcode:2018RSPTA.37670278M. doi:10.1098/rsta.2017.0278. PMC   5829179 . PMID   29459419.
  12. ↑ "A new ring to slow down antimatter – CERN" . Retrieved 21 December 2016.
  13. ↑ "Exceptionally slow antiprotons". CERN. Retrieved 28 February 2020.
  14. ↑ "Thousands of cold anti-atoms produced at CERN" (Press release). CERN. 18 September 2002.
  15. ↑ Amoretti, M.; et al. (ATHENA Collaboration) (2002). "Production and detection of cold antihydrogen atoms". Nature . 419 (6906): 456–459. Bibcode:2002Natur.419..456A. doi: 10.1038/nature01096 . PMID   12368849. S2CID   4315273.
  16. ↑ Gabrielse, G.; Fei, X.; Orozco, L.; Tjoelker, R.; Haas, J.; Kalinowsky, H.; Trainor, T.; Kells, W. (September 1990). "Thousandfold improvement in the measured antiproton mass". Physical Review Letters. 65 (11): 1317–1320. Bibcode:1990PhRvL..65.1317G. doi:10.1103/PhysRevLett.65.1317. ISSN   0031-9007. PMID   10042233.{{cite journal}}: CS1 maint: date and year (link)
  17. ↑ "Greybook: PS196". greybook.cern.ch. Archived from the original on 9 July 2021. Retrieved 6 July 2021.
  18. ↑ "ASACUSA – General". Archived from the original on 22 March 2016. Retrieved 21 December 2016.
  19. ↑ "Archived copy" (PDF). Archived from the original (PDF) on 13 December 2013. Retrieved 9 February 2011.{{cite web}}: CS1 maint: archived copy as title (link)
  20. ↑ "Archived copy". Archived from the original on 15 April 2013. Retrieved 17 February 2010.{{cite web}}: CS1 maint: archived copy as title (link)
  21. ↑ "ACE – CERN" . Retrieved 21 December 2016.
  22. ↑ Bassler, Niels; Alsner, Jan; Beyer, Gerd; DeMarco, John J.; Doser, Michael; Hajdukovic, Dragan; Hartley, Oliver; Iwamoto, Keisuke S.; Jäkel, Oliver; Knudsen, Helge V.; Kovacevic, Sandra (January 2008). "Antiproton radiotherapy". Radiotherapy and Oncology. 86 (1): 14–19. doi:10.1016/j.radonc.2007.11.028. PMID   18158194.
  23. ↑ Madsen, N. (2010). "Cold antihydrogen: a new frontier in fundamental physics". Philosophical Transactions of the Royal Society A . 368 (1924): 3671–82. Bibcode:2010RSPTA.368.3671M. doi: 10.1098/rsta.2010.0026 . PMID   20603376. S2CID   12748830.
  24. ↑ Aegis Collaboration (2018). "AEgIS Experiment". CERN .
  25. ↑ "GBAR". CERN. Retrieved 29 June 2021.
  26. ↑ "official BASE website".
  27. 1 2 Obertelli, Alexandre (2018). PUMA: antiprotons and radioactive nuclei. Memorandum. CERN. Geneva. ISOLDE and neutron Time-of-Flight Experiments Committee, INTC.
  28. ↑ "The PUMA project: Antimatter goes nomad". CERN. Retrieved 11 July 2021.
  29. ↑ Aumann, T.; Bartmann, W.; Bouvard, A.; Boine-Frankenheim, O.; Broche, A.; Butin, F.; Calvet, D.; Carbonell, J.; Chiggiato, P. (2019). PUMA: antiprotons and radioactive nuclei. Proposal. CERN. Geneva. SPS and PS Experiments Committee, SPSC.
  1. GBAR experiment
  2. Beams at AD
  3. Alpha experiment results
  4. AD's Antiproton source
  5. AD website Archived 2 August 2012 at the Wayback Machine
  6. ATHENA website
  7. ATRAP website
  8. ASACUSA website
  9. ALPHA website
  10. AEgIS website
  11. "What is the AD?". CERN. Archived from the original on 15 February 2006.
  12. "ATHENA figures and pictures". CERN. Archived from the original on 22 June 2007.
  13. Record for Antiproton Decelerator on INSPIRE-HEP

Further reading

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