Observation of thermal effects on the LEP wire scanners

Camas, J.; Fischer, C.; Gras, J J; Jung, R.; Koopman, J.

doi:10.1109/pac.1995.505647

Cited by 3 publications

(3 citation statements)

References 3 publications

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“…CERN personnel have used a variety of wire materials including 0.05 mm Be, 0.036 mm C, 0.01 mm SiC, and 0.007 mm SiO 2 . Extensive wire heating studies have been performed and reported in previous workshops and conferences (15). Another type of CERN flying-wire scanner rotationally translates a 0.03 mm carbon fiber through a beam with velocities of 10 to 20 meters per second.…”

Section: Flying Wire Profile Measurementsmentioning

confidence: 99%

Techniques for intense-proton-beam profile measurements

Gilpatrick¹

1998

AIP Conference Proceedings

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Abstract. In a collaborative effort with industry and several national laboratories, the Accelerator Production of Tritium (APT) facility and the Spallation Neutron Source (SNS) linac are presently being designed and developed at Los Alamos National Laboratory (LANL). The APT facility is planned to accelerate a 100 mA H + cw beam to 1.7 GeV and the SNS linac is planned to accelerate a 1 to 4 mA-average, H -, pulsed-beam to 1 GeV. With typical rms beam widths of 1 to 3 mm throughout much of these accelerators, the maximum average-power densities of these beams are expected to be approximately 30 and 1 MW-per-square millimeter, respectively. Such power densities are too large to use standard interceptive techniques typically used for acquisition of beam profile information. This paper will summarize the specific requirements for the beam profile measurements to be used in the APT, SNS, and the LowEnergy Development Accelerator (LEDA) -a facility to verify the operation of the first 20 MeV section of APT. This paper will also discuss the variety of profile measurement choices discussed at a recent high-average-current beam profile workshop held in Santa Fe, NM, and will present the present state of the design for the beam profile measurements planned for APT, SNS, and LEDA.

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Section: Flying Wire Profile Measurementsmentioning

confidence: 99%

Techniques for intense-proton-beam profile measurements

Gilpatrick¹

1998

AIP Conference Proceedings

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“…The forks were made of ceramics and could be observed with CCD cameras through viewing ports (1). These multi-fork tanks included the operational vertical profile wire which was made of 30 µm Quartz.…”

Section: Tests Descriptionmentioning

confidence: 99%

“…Investigations made in 1994 with the LEP wire scanners have shown that the major heating mechanism in a conducting wire comes from the electromagnetic fields (1). The effects are felt well before the lepton beam traverses the wire and outside the portion of the wire crossed by the beam.…”

Section: Introductionmentioning

confidence: 99%

Quartz wires versus carbon fibres for improved beam handling capacity of the LEP wire scanners

Fischer¹,

Jung²,

Koopman³

1997

AIP Conference Proceedings

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Abstract.After the first investigations performed in 1994, the study of thermal effects on Carbon and Quartz wires has been pursued in 1995. Carbon wires of 8 µm have been studied. Light emission resulting from the two heating mechanisms, electromagnetic fields and collision losses with the beam, were observed. Quartz wires of 10 and 30 µm were investigated and light emission due to the heating by collision with the beam was observed. The heat pattern differs completely from that of Carbon fibres. The Quartz wires withstood at 20 GeV circulating currents of at least 8 mA, the 1995 operational level in LEP. Quantitative evaluations and the influence of various dissipation processes are presented with the aim of evaluating a beam current limit.

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New methods to derive the optical and beam parameters in transport channels

Arduini

Giovannozzi

Hanke

et al. 2001

Nuclear Instruments and Methods in Physics Research Section A:

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The standard approach to compute the optical parameters and the beam emittance in a transport channel is based on the analysis of the profiles measured by three monitors. This requires the independent measurement of the dispersion function at the monitor locations and the knowledge of the value of the beam's momentum spread. In this paper different approaches based on the use of more than three beam profiles are presented. These techniques allow the determination of the complete set of four optical parameters, the betatron and dispersion functions and their derivatives, along with the beam emittance and the beam's momentum spread, simultaneously and without varying the physical parameters of the transport channel or the upstream machine. A detailed description of the different methods is carried out with a particular emphasis on their accuracy. Results of numerical simulations are presented. Accepted for publication in Nuclear Instr. and Methods in Physics Research A IntroductionThe complexity of the new generation of high-energy superconducting machines imposes tight constraints on the whole injector chain. In order to achieve the top performance in terms of luminosity of the planned CERN LHC [1], it is mandatory to preserve the value of the beam emittance through the whole chain of low-energy machines [2,3]. Although a crucial point is to avoid beam blow-up in the circular accelerators, which is obtained by carefully tuning the machines, the matching of the transfer lines to the phase space of the preceding and the subsequent machine also play a predominant role.In fact, even neglecting emittance blow-up due to the presence of possible non-linear fields, a transfer line generates transverse or longitudinal mismatch which will produce emittance increase after beam filamentation.Hence, as a consequence of the high performance required for the physics experiments, there has been a renewed interest in optics issues in transfer lines, with special emphasis on automated algorithms to measure optical parameters with the aim of computing mismatch factors, and, eventually, of applying corrections (see Ref. [4] for an overview of this field). These algorithms are usually devoted to the correction of the beam trajectory, via dedicated steering magnets, or to reducing the injection mismatch by using quadrupole magnets. An application of these concepts to the transfer line joining the PS and the SPS machines allowed a substantial improvement of the beam quality [5].Every correction procedure is based on a set of measured parameters to be compared with their theoretical values. Two different approaches are available. The first one deals with the measurement of the optical parameters by trajectory fit on Beam Position Monitor (BPM) data [6]. It allows the reconstruction of the transfer matrices between different BPMs and, in particular, the value of the dispersion function.The second technique allows to derive not only the optical parameters α, β, γ but also the beam characteristics, emittance and beam's momentum sp...

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Observation of thermal effects on the LEP wire scanners

Cited by 3 publications

References 3 publications

Techniques for intense-proton-beam profile measurements

Techniques for intense-proton-beam profile measurements

Quartz wires versus carbon fibres for improved beam handling capacity of the LEP wire scanners

New methods to derive the optical and beam parameters in transport channels

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