publication . Article . 2011

Effect of impedance and higher order chromaticity on the measurement of linear chromaticity

V. H. Ranjbar; C. Y. Tan;
Open Access English
  • Published: 01 Aug 2011 Journal: Physical Review Special Topics. Accelerators and Beams, volume 14, issue 8 (issn: 1098-4402, Copyright policy)
  • Publisher: American Physical Society
Abstract
The combined effect of impedance and higher order chromaticity can act on the beam in a nontrivial manner which can cause a tune shift which depends on the relative momenta with respect to the 'on momentum' particle ({Delta}p/p). Experimentally, this tune shift affects the measurement of the linear chromaticity which is traditionally measured with a change of {Delta}p/p. The theory behind this effect will be derived in this paper. Computer simulations and experimental data from the Tevatron will be used to support the theory.
Persistent Identifiers
Subjects
arXiv: Physics::Accelerator Physics
free text keywords: Physics and Astronomy (miscellaneous), Nuclear and High Energy Physics, Surfaces and Interfaces, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, lcsh:QC770-798, Particle, Computational physics, Tevatron, Electrical impedance, Optics, business.industry, business, Momentum, Particle accelerator, law.invention, law, Physics, Beam (structure), Chromaticity

[1] Uncoalesced beam in the Tevatron means that there are 30 bunches in adjacent buckets.

[2] One coalesced bunch means that seven bunches from the main injector are coalesced into one high current bunch and injected into the Tevatron. For our experiment, four coalesced bunches separated by 21 buckets are used.

[3] S. Y. Lee, Accelerator Physics (World Scientific, Singapore, 1999), pp. 199-206.

[4] P. M. Ivanov et al., in Proceedings of the 20th Particle Accelerator Conference, Portland, OR, 2003 (IEEE, New York, 2003), p. 3062; in Proceedings of the 21st Particle Accelerator Conference, Knoxville, 2005 (IEEE, Piscataway, NJ, 2005), p. 1714; in Proceedings of the 21st Particle Accelerator Conference, Knoxville, 2005 (IEEE, Piscataway, NJ, 2005), p. 2756; P. M. Ivanov, F0 Lambertson liner review (2003), internal FNAL document.

[5] V. H. Ranjbar and P. Ivanov, Phys. Rev. ST Accel. Beams 11, 084401 (2008).

[6] http://www.wolfram.com/.

[7] C. Y. Tan and V. H. Ranjbar, Phys. Rev. ST Accel. Beams 11, 032802 (2008).

[8] There is a small change in the local oscillator (LO) frequency of f < 20 Hz used for up-conversion and down-conversion because the low level rf, from which the LO of 21.4 MHz is derived, is changed for chromaticity measurements.

[9] C. Y. Tan, Nucl. Instrum. Methods Phys. Res., Sect. A 602, 352 (2009).

[10] http://www-ap.fnal.gov/~hjkim/.

[11] A. Burov and C. Y. Tan, in Proceedings of 2011 Particle Accelerator Conference, New York, NY, WEP116 [http://www.c-ad.bnl.gov/pac2011/proceedings/ papers/wep116.pdf ].

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