Effects of RF noise on longitudinal emittance growth in the Tevatron

Steimel, J.; Lebedev, Valeri; Gonin, I.; Khabibouline, T.; Reid, J.; Romanov, Gennady; Shiltsev, V.; Tollestrup, A.

doi:10.1109/pac.2003.1288837

Cited by 7 publications

(7 citation statements)

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“…They correspond to the gas scattering lifetime of 380 hours, and the bunch lengthening due to RF noise of 2.2⋅10 -3 rad 2 /hour. RF phase noise was measured directly [11] and agrees with the fit to the model within the measurement accuracy (factor of 2). The computed proton and antiproton intensities are close to the measured ones as can be seen in Figure 6.…”

Section: Luminosity Evolutionsupporting

confidence: 60%

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Beam physics at Tevatron complex

Lebedev

Proceedings of the 2003 Bipolar/BiCMOS Circuits and Technology Meeting (IEEE Cat. No.03CH37440)

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The challenge of achieving the Tevatron Run II luminosity goal of 3⋅10 32 cm -2 s -1 requires high level of engineering and machine operation, good and reliable diagnostics, and clear understanding of the underlying accelerator physics. Recent history demonstrated steady increase of the Tevatron luminosity, which was supported by each of the three listed above items. This report reviews major developments in the accelerator physics, which contributed in the Run II luminosity growth. Present limitations of the luminosity and projections of further luminosity growth are also discussed.

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Section: Luminosity Evolutionsupporting

confidence: 60%

“…Accumulator [6] stacks antiprotons with an average accumulation rate of ~10 11 per hour, so that after 20 hours the stack of ~2⋅10 12 antiprotons can be accumulated. The total number of antiprotons along with the longitudinal and transverse emittances are the major parameters which determine the collider luminosity.…”

Section: Ibs In Accumulatormentioning

confidence: 99%

Beam physics at Tevatron complex

Lebedev

Proceedings of the 2003 Bipolar/BiCMOS Circuits and Technology Meeting (IEEE Cat. No.03CH37440)

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“…Longitudinal instabilities, RF noise, and intra-beam scattering can cause particles to leak out of RF buckets and into satellites or into the abort gaps [25,26] see Fig. 15.…”

Section: Abort Gap Monitorsmentioning

confidence: 99%

Beam instrumentation for the Tevatron collider

2009

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The Tevatron in Collider Run II (2001-present) is operating with six times more bunches and many times higher beam intensities and luminosities than in Run I (1992)(1993)(1994)(1995). Beam diagnostics were crucial for the machine start-up and the never-ending luminosity upgrade campaign. We present the overall picture of the Tevatron diagnostics development for Run II, outline machine needs for new instrumentation, present several notable examples that led to Tevatron performance improvements, and discuss the lessons for future colliders. FIGURE 2. a) (top) Evolution of beam losses (left axis) in 2002-2009.Red shows fractional loss of antiprotons between injection into the Tevatron and start of collisions, next (blue) one is for loss of protons, greenfractional reduction of the luminosity integral caused by beam-beam effects in collisions. b) (bottom) Injection process and beginning of the luminosity run in store #7040 (May 11, 2009). The square dots are the total proton and antiproton bunch intensities, respectively, as measured by the Fast Bunch Integrator (FBI) system. The line on the right represents the start of the HEP store with an initial peak luminosity of 321×10 30 cm -2 s -1 . The spikes in the beam intensities are instrumentation artifacts that occur when antiproton bunches pass through proton bunch integration gates during longitudinal cogging [1]. 4 BEAM DIAGNOSTICS DEVELOPMENTSOperation of a superconducting magnet hadron collider, like Fermilab's Tevatron, requires a great deal of care, understanding of beam conditions, and trust in the beam diagnostics, because comparatively innocent little imperfections can lead to either beam blow-up and luminosity loss or to beam loss and quench of SC magnets. In the Tevatron such a quench results in 2-4 hours of magnet recovery time and up to 8-16 hours of no-luminosity time needed to produce the antiprotons needed for the next High Energy Physics (HEP) store. Over 8 years of operations we witnessed machine downtimes due to 0.5-1% of beam intensity loss, poor beam lifetime, 0.5-1 mm orbit error, collimator malfunctioning, sequencer error, excursions of tunes or coupling of the order of few 0.001 or several units of chromaticity, instability occurrences, or malfunctioning of kickers, high voltage electrostatic separators, or one of hundreds of power supplies, etc. Naturally, these peculiarities were reflected in the kinds of beam diagnostics we developed (e.g. minimization of their invasiveness) and the way they were exploited (fast data-logging, convenience for post-mortem analysis, etc.).In the Tevatron, the protons and antiprotons circulate within a single beam pipe, so electrostatic separators are used to kick the beams onto distinct helical orbits to allow head-on collisions only at the desired interaction points. (See Fig. 3.) At 150 GeV, separation is limited to ~(10-22) mm by physical aperture, while the separation above 600 GeV, ~(3-6 mm), is limited by the breakdown (spark) rate of the separators at high voltage. Long-range beam effects degrade beam...

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“…Longitudinal instabilities, RF noise and Intra-Beam Scattering cause particles to leak out of RF buckets into satellites or into the abort gaps [22,23]. There are three 2.6 μs gaps between 3 trains of 12 bunches each separated by 396 ns.…”

Section: Abort Gap Monitorsmentioning

confidence: 99%

Tevatron Instrumentation: Boosting Collider Performance

Shiltsev¹,

Jansson²,

Moore³

2006

AIP Conference Proceedings

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Abstract. The Tevatron in Collider Run II (2001-present) is operating with six times more bunches, many times higher beam intensities and luminosities than in Run I (1992Run I ( -1995. Beam diagnostics were crucial for the machine start-up and the never-ending luminosity upgrade campaign. We present the overall picture of the Tevatron diagnostics development for Run II, outline machine needs for new instrumentation, present several notable examples that led to Tevatron performance improvements, and discuss the lessons for the next big machines -LHC and ILC.

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Effects of RF noise on longitudinal emittance growth in the Tevatron

Cited by 7 publications

References 1 publication

Beam physics at Tevatron complex

Beam physics at Tevatron complex

Beam instrumentation for the Tevatron collider

Tevatron Instrumentation: Boosting Collider Performance

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