Commissioning of the second Tevatron Electron Lens and beam study results

Kamerdzhiev, V.; Fellenz, B.; Hively, R.; Kuznetsov, G. F.; Olson, M.; Pfeffer, H.; Saewert, G.; Scarpine, V.; Shiltsev, V.; Zhang, X.L.

doi:10.1109/pac.2007.4440871

Cited by 3 publications

(5 citation statements)

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“…This result has been confirmed in several beam studies. Such an effect can be explained by a positive tune shift introduced by the TEL (tune shift of about 0.0014 at J e pk =0.6 A has been confirmed [3]) pushing the P12 tune away from the resonance. However, it is not yet clear whether it is the only mechanism responsible for the significant lifetime improvement.…”

Section: Resultsmentioning

confidence: 88%

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Experimental and simulation studies of beam-beam compensation with tevatron electron lenses

Kamerdzhiev

Alexahin

Shiltsev

et al. 2007

2007 IEEE Particle Accelerator Conference (PAC)

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Initially the Tevatron Electron Lenses (TELs) were intended for compensation of the beam-beam effect on the antiproton beam [1]. Owing to recent increase in the number of antiprotons and reduction in their emittance, it is the proton beam now that suffers most from the beambeam effect [2]. We present results of beam studies, compare them with the results of computer simulations using LIFETRAC code and discuss possibilities of further improvements of the Beam-Beam Compensation efficiency in the Tevatron. TEVATRON ELECTRON LENSESThree types of electron guns were developed for beambeam compensation (BBC). Currently, both electron lenses [3] are equipped with electron guns utilizing smooth-edge-flat-top (SEFT) transverse current density distribution. Fig.1 shows all three distributions. All experimental and computer simulation results presented in this paper were obtained with SEFT profiles. Accurate longitudinal and transverse electron beam alignment is crucial for successful beam-beam compensation. Figure 2 shows how TEL2 was timed for the beam-beam compensation experiments on proton bunch #12. The cathode and collector current transformers (CT), report electron current leaving the cathode and the one arriving on the collector. The flat top of the collector signal is distorted by waves caused by a proton bunch (P12) passing through the electron beam. This feature is often used for alignment optimization. The pickup signal (see Fig.2) featuring proton and antiproton bunches as well as the ac component of the electron pulse provides valuable information for longitudinal alignment. One can see that at TEL2 location the time separation of the counter rotating proton and antiproton bunches is less than 100 ns. However, the transverse proton-antiproton separation (see Fig. 3) allows performing beam-beam compensation of one species without affecting another. Transverse alignment of all three beams in TEL2 is shown in Fig. 3. One can see that the proton and antiproton beams are separated both in horizontal and in vertical planes. All the protons, even those with very large betatron amplitudes pass through the electron beam and thus experience the same tune shift.

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Section: Resultsmentioning

confidence: 88%

“…Currently, both electron lenses [3] are equipped with electron guns utilizing smooth-edge-flat-top (SEFT) transverse current density distribution. Fig.1 shows all three distributions.…”

Section: Tevatron Electron Lensesmentioning

confidence: 99%

Experimental and simulation studies of beam-beam compensation with tevatron electron lenses

Kamerdzhiev

Alexahin

Shiltsev

et al. 2007

2007 IEEE Particle Accelerator Conference (PAC)

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“…Thirdly, the second electron lens was built and installed at the A11 location of the Tevatron ring [19,8] that allowed us to conduct dedicated beam-beam compensation studies very oftenultimately, in every HEP storewith one of the lenses while the other one is always dedicated to the abort gap cleaning (a standard TEL job since early Run IIsee Refs. [20,16]).…”

Section: Improvement Of Proton Beam Intensity Lifetime and Luminosity...mentioning

confidence: 99%

Experimental studies of compensation of beam–beam effects with Tevatron electron lenses

et al. 2008

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Applying the space-charge forces of a low-energy electron beam can lead to a significant improvement of the beam-particle lifetime limit arising from the beam-beam interaction in a highenergy collider [1]. In this article we present the results of various beam experiments with "electron lenses," novel instruments developed for the beam-beam compensation at the Tevatron, which collides 980-GeV proton and antiproton beams. We study the dependencies of the particle betatron tunes on the electron beam current, energy and position; we explore the effects of electron-beam imperfections and noises; and we quantify the improvements of the high-energy beam intensity and the collider luminosity lifetime obtained by the action of the Tevatron Electron Lenses.

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“…This level, though less than desired, was similar to the level of the TEL1 modulator. It was sufficient to be useful for the TEL2 experiments that were carried out [1,5].…”

Section: Challengesmentioning

confidence: 99%

“…The 2 nd Tevatron Electron Lens (TEL2) was installed and commissioned in 2006 in the framework of BeamBeam Compensation project at Fermilab [1]. The project aims at reducing non-luminous proton/antiproton losses in collider operation by mitigating head-on and long range beam-beam effects [2].…”

Section: Introductionmentioning

confidence: 99%