Handbook of Accelerator Physics and Engineering

Chao, Alexander W.; Tigner, M.

doi:10.1142/3818

Cited by 324 publications

(222 citation statements)

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“…6 The coupling coefficient is related to the frequencies of the coupled modes in the 9-cell resonator by the formula f n f 0 ͞ p 1 1 2 k cell cos͑np͞9͒ where f 0 is the resonant frequency of a single cell and 1 # n # 9. a Following common usage in ac circuits and the convention adopted in Ref. [19], p. 523, we define the shunt impedance by the relation R V 2 ͞2P, where P is the dissipated power and V is the peak voltage in the equivalent parallel LCR circuit. Note that another definition is common, which has also been used in the TESLA Conceptual Design Report, R V 2 ͞P, leading to a factor of 2 larger shunt impedance.…”

Section: Cavity Geometrymentioning

confidence: 99%

Superconducting TESLA cavities

Aune¹,

Bandelmann²,

Bloess³

et al. 2000

Phys. Rev. ST Accel. Beams

346

266

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The conceptional design of the proposed linear electron-positron collider TESLA is based on 9-cell 1.3 GHz superconducting niobium cavities with an accelerating gradient of E acc $ 25 MV͞m at a quality factor Q 0 $ 5 3 10 9 . The design goal for the cavities of the TESLA Test Facility (TTF) linac was set to the more moderate value of E acc $ 15 MV͞m. In a first series of 27 industrially produced TTF cavities the average gradient at Q 0 5 3 10 9 was measured to be 20.1 6 6.2 MV͞m, excluding a few cavities suffering from serious fabrication or material defects. In the second production of 24 TTF cavities, additional quality control measures were introduced, in particular, an eddy-current scan to eliminate niobium sheets with foreign material inclusions and stringent prescriptions for carrying out the electronbeam welds. The average gradient of these cavities at Q 0 5 3 10 9 amounts to 25.0 6 3.2 MV͞m with the exception of one cavity suffering from a weld defect. Hence only a moderate improvement in production and preparation techniques will be needed to meet the ambitious TESLA goal with an adequate safety margin. In this paper we present a detailed description of the design, fabrication, and preparation of the TESLA Test Facility cavities and their associated components and report on cavity performance in test cryostats and with electron beam in the TTF linac. The ongoing research and development towards higher gradients is briefly addressed.

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Section: Cavity Geometrymentioning

confidence: 99%

Superconducting TESLA cavities

Aune¹,

Bandelmann²,

Bloess³

et al. 2000

Phys. Rev. ST Accel. Beams

346

266

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“…In other words, the electric field of the opposite bunch distorts the charge distribution of the probe bunch and, therefore, it influences the transverse beam size as well as the measured luminosity. The general theory of the dynamic- effect could be found in [11,12]. In the current implementation, it is assumed that the undistorted bunch has a Gaussian The measured rates could be decreased up to 10% as shown in Fig.…”

Section: Dynamic-β Effectmentioning

confidence: 99%

Beam-dynamic effects at the CMS BRIL van der Meer scans

Babaev

2018

J. Inst.

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The CMS Beam Radiation Instrumentation and Luminosity Project (BRIL) is responsible for the simulation and measurement of luminosity, beam conditions and radiation fields in the CMS experiment. The project is engaged in operating and developing new detectors (luminometers), adequate for the experimental conditions associated with high values of instantaneous luminosity delivered by the CERN LHC. BRIL operates several detectors based on different physical principles and technologies. Precise and accurate measurements of the delivered luminosity is of paramount importance for the CMS physics program. The absolute calibration of luminosity is achieved by the van der Meer method, which is carried out under specially tailored conditions. This paper presents models used to simulate of beam-dynamic effects arising due to the electromagnetic interaction of colliding bunches. These effects include beam-beam deflection and dynamic-beta effect. Both effects are important to luminosity measurements and influence calibration constants at the level of 1-2%. The simulations are carried out based on 2016 CMS van der Meer scan data for proton-proton collisions at a center-of-mass energy of 13 TeV.

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“…(7), Sec. 3.3.1 from [33]]. The larger beam emittance washes out noise suppression and microbunching alike by both scrambling particle positions [34] and expanding the beam size in the undulator (which reduces transverse coherence, see below); i.e., inserting the screen makes the beam behave like it has a shot noise distribution.…”

Section: Determining the Shot Noise Levelmentioning

confidence: 99%

Subradiant spontaneous undulator emission through collective suppression of shot noise

Ratner

Hemsing

Gover

et al. 2015

Phys. Rev. ST Accel. Beams

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The phenomenon of Dicke's subradiance, in which the collective properties of a system suppress radiation, has received broad interest in atomic physics. Recent theoretical papers in the field of relativistic electron beams have proposed schemes to achieve subradiance through suppression of shot noise current fluctuations. The resulting "quiet" beam generates less spontaneous radiation than emitted even by a shot noise beam when oscillating in an undulator. Quiet beams could have diverse accelerator applications, including lowering power requirements for seeded free-electron lasers and improving efficiency of hadron cooling. In this paper we present experimental observation of a strong reduction in undulator radiation, demonstrating the feasibility of noise suppression as a practical tool in accelerator physics.

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Handbook of Accelerator Physics and Engineering

Cited by 324 publications

References 0 publications

Superconducting TESLA cavities

Superconducting TESLA cavities

Beam-dynamic effects at the CMS BRIL van der Meer scans

Subradiant spontaneous undulator emission through collective suppression of shot noise

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