Results of bent crystal channeling and collimation at the Relativistic Heavy Ion Collider

Fliller, R.; Drees, A.; Gassner, D.; Hammons, L.; McIntyre, G.; Peggs, S.; Trbojević, D.; Biryukov, V.M.; Chesnokov, Yu. A.; Терехов, В. И.

doi:10.1103/physrevstab.9.013501

Cited by 60 publications

(51 citation statements)

References 11 publications

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“…The studies of beam extraction and collimation assisted by channeling in a bent crystal have progressed well in recent decades [1][2][3][4][5][6][7][8][9][10]. The technique was applied at up to world highest energy [4,8], in good agreement with predictions [11].…”

Section: Introductionsupporting

confidence: 52%

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Possibility of crystal extraction and collimation in the sub-GeV range

Bellucci

Biryukov

2007

Phys. Rev. ST Accel. Beams

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Bent crystal situated in a circulating beam can serve for efficient slow extraction or active collimation of the beams. This technique, well established at 1-1000 GeV, could be efficient also at the energies as low as 0.1-1 GeV according to the computer simulations presented in this paper. Applications might include halo scraping in the spallation neutron sources or slow extraction from medical synchrotrons.

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Section: Introductionsupporting

confidence: 52%

“…[23]. The code had earlier been successfully tested in crystal extraction experiments at CERN SPS [1], Tevatron [4], RHIC [9], and IHEP U-70 [6].…”

Section: Introductionmentioning

confidence: 99%

Possibility of crystal extraction and collimation in the sub-GeV range

Bellucci

Biryukov

2007

Phys. Rev. ST Accel. Beams

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“…Several years ago a study of crystal collimation was carried out at the superconducting Relativistic Heavy Ion Collimator (RHIC) at Brookhaven 6 . Because of limitations of useful space in the accelerator lattice the crystal was mounted at an unfavorable location where the angular divergence was high.…”

Section: The Challenge Of Collider Collimationmentioning

confidence: 99%

<title>Channeling collimation studies at the Fermilab Tevatron</title>

et al. 2007

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Bent crystal channeling has promising advantages for accelerator beam collimation at high energy hadron facilities such as the LHC. This significance has been amplified by several surprising developments including multi-pass channeling and the observation of enhanced deflections over the entire arc of a bent crystal. The second effect has been observed both at RHIC and recently at the Tevatron. Results are reported showing channeling collimation of the circulating proton beam halo at the Tevatron. Parenthetically, this study is the highest energy proton channeling experiment ever carried out. The study is continuing.Keywords: Channeling, collimation, accelerator, Tevatron THE CHALLENGE OF COLLIDER COLLIMATIONDuring the design of the Superconducting Super Collider (SSC) it was recognized that collimating the intense proton beams required for high luminosity posed daunting challenges. A halo develops around any circulating beam due to many effects such as beam-gas and beam-beam interactions. Superconducting magnets can be quenched or destroyed if they scrape even a tiny portion of the beam. Collider detector devices such as silicon strip detectors are even more sensitive.In so-called single stage conventional collimation the beam halo is scraped by a collimator moved into the halo. Typically the collimator is a 1.5 m long block of steel or other medium or high-Z material. A certain fraction of the halo will survive, either by traversing the length of the collimator or by scattering out of the collimator block. Suppressing the out-scattered particles can be quite difficult. A more sophisticated way to handle the out-scattered particles is to go to a two-stage collimation system 1 . A thin primary target is used to scatter the beam out by increasing the amplitude of the betatron oscillations of the halo particles and thereby increasing the impact parameters on to secondary collimators during the next turns without influencing the unscattered beam.At the SSC, Mokhov and his colleagues 2 proposed an innovative solution to the collimation problem. In their arrangement an aligned, bent single crystal is used to deflect the beam out into a collimator much as a magnetic septum would. However, using the crystal results in a much higher deflection per unit length with little effective septum width. Since the SSC design there have been several developments that have made crystal collimation even more promising. One was a fuller understanding of so-called crystal multi-pass extraction first observed at CERN 3 . The other was the development of several approaches at the Institute for High Energy Physics (IHEP) and the Petersburg Nuclear Physics Institute (PNPI) for producing very short crystal bending lengths characteristically using anticlastic crystal deformations 4 . In view of the promise for both extraction and collimation the SSC sponsored a research program on crystal extraction at the Tevatron. That experiment, E853 5 , showed that extraction was possible in the context of a superconducting accelerator. FERMILA...

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“…Ideally this would be in terms of a diffusion treatment in the spirit of the diffusion calculation for electron dechanneling by Backe et al 14 (2) where Z i is the incident particle charge, d p is the interplanar distance and a TF is the Thomas-Fermi screening length. At 1 TeV this leads to λ D = 510 mm for (110) planar proton channeling in Si.…”

Section: Dechanneling Estimatesmentioning

confidence: 99%

Negative Particle Planar and Axial Channeling and Channeling Collimation

Carrigan¹

2010

Charged and Neutral Particles Channeling Phenomena

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While information exists on high energy negative particle channeling there has been little study of the challenges of negative particle bending and channeling collimation. Partly this is because negative dechanneling lengths are relatively much shorter. Electrons are not particularly useful for investigating negative particle channeling effects because their material interactions are dominated by channeling radiation. Another important factor is that the current central challenge in channeling collimation is the proton-proton Large Hadron Collider (LHC) where both beams are positive. On the other hand in the future the collimation question might reemerge for electron-positron or muon colliders. Dechanneling lengths increase at higher energies so that part of the negative particle experimental challenge diminishes. In the article different approaches to determining negative dechanneling lengths are reviewed. The more complicated case for axial channeling is also discussed. Muon channeling as a tool to investigate dechanneling is also discussed. While it is now possible to study muon channeling it will probably not illuminate the study of negative dechanneling.

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Results of bent crystal channeling and collimation at the Relativistic Heavy Ion Collider

Cited by 60 publications

References 11 publications

Possibility of crystal extraction and collimation in the sub-GeV range

Possibility of crystal extraction and collimation in the sub-GeV range

<title>Channeling collimation studies at the Fermilab Tevatron</title>

Negative Particle Planar and Axial Channeling and Channeling Collimation

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