Advantages of axially aligned crystals used in positron production at future linear colliders

Artru, X.; Chehab, R.; Chevallier, M.; Strakhovenko, V. M.

doi:10.1103/physrevstab.6.091003

Cited by 16 publications

(14 citation statements)

References 13 publications

(18 reference statements)

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“…This gives rise to photons of high energy and high degree of polarization. The scattered photons would then be converted to pairs using a solid target that could possibly be crystalline [37].…”

Section: Depolarizationmentioning

confidence: 99%

Strong field processes in beam-beam interactions at the Compact Linear Collider

Esberg

Uggerhøj

Dalena

et al. 2014

Phys. Rev. ST Accel. Beams

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The demand for high luminosity in the next generation of linear e þ e − colliders necessitates extremely dense beams, giving rise to strong fields at the collision point, and therefore the impact of the field on the physical processes occurring at the interaction point must be considered. These processes are well described by the interaction of the individual lepton with the field of the oncoming bunch, and they depend strongly on the beamstrahlung parameter ϒ which expresses the field experienced by the lepton in units of the critical field. In this paper, we describe calculations and simulations of strong field processes-also of higher order-at the interaction point.

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Section: Depolarizationmentioning

confidence: 99%

Strong field processes in beam-beam interactions at the Compact Linear Collider

Esberg

Uggerhøj

Dalena

et al. 2014

Phys. Rev. ST Accel. Beams

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“…These results confirm that the steady-state heat load on the crystal target as a function of the beam repetition rate is clearly reduced by about 20% compared with that of the previously used tungsten target. The power densities deposited on the crystal and conventional targets have been investigated theoretically by Artru et al [6] at an incident electron energy of 2 -10 GeV. Based on their results, the total energy deposit on a 10-mmthick crystal is estimated to be 20% lower than that of a 14-mm-thick conventional tungsten at an incident electron energy of 4 GeV.…”

Section: B Operational Performancementioning

confidence: 99%

“…Intensive theoretical investigations [3][4][5][6] have indicated that the optimum thickness is less for the crystal target and that the energy deposition in the crystal target is considerably reduced compared with that of a conventional target. Also, they have shown that the crystal effect is much larger at higher incident electron energies.…”

Section: Introductionmentioning

confidence: 99%

First application of a tungsten single-crystal positron source at the KEK B factory

Suwada

Satoh

Furukawa

et al. 2007

Phys. Rev. ST Accel. Beams

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A new tungsten single-crystal target has been successfully employed at the positron source of the KEKB injector linac. The crystal thickness was determined to be 10.5 mm based on previous systematic measurements of the positron-production efficiency. The crystal axis, h111i, was precisely aligned to the direction of the 4-GeV primary electron beam. The positron yield increased by 25% compared to that for a conventional tungsten plate with a thickness of 14 mm. On the contrary, the steady-state heat load on the crystal target decreased by 20%. After a two-month operation, no degradation of the positronproduction efficiency was observed, and the crystal target has been stably operating at the KEK B factory.

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“…Chehab and his colleagues at LAL d'Orsay [5], and experimental studies has been carried out with the 1.3-GeV synchrotron in Institute for Nuclear Study, the University of Tokyo [6], at CERN with the experiment WA 103 [7,8] and the KEKB linac at KEK [9]. Simulations have shown [10] that a crystal converter presents the advantage of less energy deposition than the equivalent amorphous converter (giving the same positron yield). However, to avoid significant energy deposition in the crystal, due to large incident beam power, which could affect the available string potential -due to thermal vibrations -a separation between the thin crystal-radiator and the thicker amorphous converter led to the hybrid source scheme.…”

Section: Introductionmentioning

confidence: 99%

Development of an intense positron source using a crystal-amorphous hybrid target for linear colliders

Uesugi¹,

Akagi²,

Chehab³

et al. 2014

Nuclear Instruments and Methods in Physics Research Section B:

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In a conventional positron source driven by a few GeV electron beam, a high amount of heat is loaded into a positron converter target to generate intense positrons required by linear colliders, and which would eventually damage the converter target. A hybrid target, composed of a single crystal target as a radiator of intense gamma-rays, and an amorphous converter target placed downstream of the crystal, was proposed as a scheme which could overcome the problem. This paper describes the development of an intense positron source with the hybrid target. A series of experiments on positron generation with the hybrid target has been carried out with a 8-GeV electron beam at the KEKB linac. We observed that positron yield from the hybrid target increased when the incident electron beam was aligned to the crystal axis and exceeded the one from the conventional target with the converter target of the same thickness, when its thickness is less than about 2 radiation length. The measurements in the temperature rise of the amorphous converter target was successfully carried out by use of thermocouples. These results lead to establishment to the evaluation of the hybrid target as an intense positron source.

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Advantages of axially aligned crystals used in positron production at future linear colliders

Cited by 16 publications

References 13 publications

Strong field processes in beam-beam interactions at the Compact Linear Collider

Strong field processes in beam-beam interactions at the Compact Linear Collider

First application of a tungsten single-crystal positron source at the KEK B factory

Development of an intense positron source using a crystal-amorphous hybrid target for linear colliders

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