Tevatron extraction apparatus updated Apr. 13, 2016 ( - subject line must be sensible)

Channeling Formulary

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Bent crystal layout
              at C0

The apparatus

The bent crystal for E853 was located at B48. The abort magnet string of kickers replaced by the crystal consisted of four 1.8 m modules with peak fields of 3.7 kG giving a vertical deflection of 640 Árad. Removal of the upstream kicker module provided sufficient space for the crystal. The bent crystal on the outside of the ring deflected protons up through quadrupoles (Q) into the field-free region of the Lambertson magnets. Extraction consisted of two parts: a vertical kick into the field-free region of a Lambertson magnet string and horizontal separation of the circulating beam from the extracted beam by the Lambertsons. After the Lambertson magnets the extracted beam traversed two instrumented air gaps approximately 100 meters downstream of the crystal and then entered a beam dump. Air gaps, separated by 40 meters, were instrumented with several scintillators. Thin movable counters could scan the beam profile. A fluorescent screen coupled to a CCD camera in the first air gap also provided a digital readout of the beam‑profile for run‑time diagnostics.