Tevatron extraction  updated Apr 11, 2016  (carrigan@fnal.gov - subject line must be sensible)

Channeling Formulary

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This page is dedicated to the memories of Thornton Murphy and Tim Toohig, key participants in the Fermilab channeling program.

Introduction

In the early 1990s a fixed target experiment was proposed for the Superconducting Super Collider (SSC) program to study heavy-flavor physics using a tiny fraction of the 20 TeV circulating beam extracted with bent crystal channeling. Conventional methods of beam extraction at such high energies posed problems with no obvious cost-effective solutions. E853 at Fermilab was designed to study the feasibility of this approach. The goals of E853 were to extract 106 900 GeV/c protons/second with 1012 protons circulating in the Tevatron, to study the extraction efficiency, to show that the luminosity lifetime of the circulating beam was not adversely affected, and to investigate the backgrounds created at the two Tevatron collider experiments. Losses at the  collider experiments, CDF had to be kept to a tolerable level. A central concern for the E853 operation was that losses be minimized so that the superconducting Tevatron magnets were not quenched. The experiment was wildly successful. All the goals were met. Channeling extraction was observed at a collider, a superconducting one at that, for the first and only time so far. E853 demonstrated that useful beams can be extracted from a superconducting accelerator during high luminosity collider operations without unduly affecting the background at the collider detectors.

History

  • First seen at Dubna - 1979
  • investigated at Serpukhov, CERN - 1980s
  • Tevatron - 1995 to 1996
E853 produced the highest energy extracted particle beam ever (900 GeV) and in the process observed particle channeling at the highest energy reached up to that time. Luminosity driven extraction, where collisions in a collider create halo, was observed for the first time.

In fact, E853 was perhaps the most successful experiment conducted under the ill-fated SSC program.
References
First Results from Bent Crystal Extraction at the Tevatron C. Murphy et al., Nucl. Instr. Methods Phys. Res., B119, 231 (1996)
First observation of luminosity-driven extraction using channeling R. Carrigan, et al., Phys. Rev. ST - Acc  & Beams 1, 022801 (1998)
Beam extraction studies at 900 GeV using a channeling crystal R. Carrigan, et al., Phys. Rev. AB, vol. 5, E043501 (2002)

E853 Apparatus

E 853 Results