Synchrotron radiation contributions to optical diffraction radiation measurements

Naumenko, G. A.

doi:10.1016/s0168-583x(02)01746-9

Cited by 9 publications

(6 citation statements)

References 9 publications

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“…The feasibility and advantages of this technique have been first demonstrated by measurements performed at ATF at KEK [4][5][6]. However, these results have also pointed out some difficulties related to the experimental setup, in particular the low ODR signal-tonoise ratio, mainly affected by the unavoidable synchrotron radiation (SR) background [7] produced by the same beam in the upstream magnetic elements of the transport line. Moreover, an accurate and nontrivial control of the beam trajectory is required due to the ambiguity of radiation produced by a pointlike beam passing through an aperture off center, and a centered Gaussian distributed beam with a transverse rms (root mean square) beam size equal to this offset with respect to the slit center according to Eq.…”

Section: Introductionmentioning

confidence: 99%

Nonintercepting electron beam size monitor using optical diffraction radiation interference

Cianchi

Castellano

Catàni

et al. 2011

Phys. Rev. ST Accel. Beams

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In recent years, the use of diffraction radiation (DR), emitted when a charged particle beam passes\ud through a rectangular slit, has been proposed and successfully tested as a nonintercepting diagnostic of\ud high brightness beams. However, some problems related to the control of the particle trajectory through\ud the slit still remain. If an additional slit is placed in front of the first one, at a distance shorter than the\ud radiation formation length, interference between the forward diffraction radiation from the upstream slit\ud and the backward diffraction radiation from the downstream slit can be observed. In this paper we report\ud the first experimental observation of this effect, which we call here optical diffraction radiation\ud interference (ODRI). If the two slits have different dimensions and are not aligned on the same axis,\ud the properties of the ODRI pattern can be effectively used for nonintercepting beam diagnostics,\ud especially for the unambiguously determination of the beam size. Indeed, the advantage of ODRI\ud compared with a single aperture DR screen is due to the reduction of synchrotron radiation background,\ud the increase of sensitivity for transverse beam dimensions, and the possibility to separate effects caused by\ud the beam size and by beam offset within the slit

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Section: Introductionmentioning

confidence: 99%

Nonintercepting electron beam size monitor using optical diffraction radiation interference

Cianchi

Castellano

Catàni

et al. 2011

Phys. Rev. ST Accel. Beams

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“…SR is the electromagnetic radiation emitted when charged particles are radially accelerated [36]. SR acts as an undesired background in ODR measurements, because the SR intensity can be similar to or higher than the ODR signal, resulting in destructive interference and poor reproducibility of the measurements [37,38]. In particular, SR produced upstream and reflected from the internal beampipe surface copropagates quasicollinearly with the beam, so in the angular distribution created in the back focal plane of the lens it is concentrated in the center of the ODR angular pattern, causing an overestimation of the beam size.…”

Section: A Synchrotron-radiation Suppressionmentioning

confidence: 99%

Noninvasive Micrometer-Scale Particle-Beam Size Measurement Using Optical Diffraction Radiation in the Ultraviolet Wavelength Range

et al. 2020

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We present recent achievements in the application of optical diffraction radiation (ODR) to the measurement of the transverse beam size of a 1.3 GeV micrometer-size electron beam performed with an instrument installed in the extended extraction line of the KEK Accelerator Test Facility. ODR is a recent technique for the measurement of the transverse size and emittance of highly relativistic particle beams. ODR has the advantage of being a noninvasive and relatively inexpensive technique and is a candidate for the operation of linear particle accelerators, where no simple alternatives (e.g., synchrotron radiation) are available. In an effort to improve the resolution and performance, we establish an alternative target microfabrication technology, adopt solutions to improve the signal-to-noise ratio, and perform an experiment in the UV spectrum at 250 nm. With such a configuration, a transverse beam size as low as 3 μm is measured, drastically improving on past measurements reported in the literature. In light of these results, ODR, when combined with a high-resolution optical-transition-radiation monitor, represents a credible diagnostics solution for low-emittance high-intensity particle beams.

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“…Nevertheless two main problems remained: the low ODR signal-to-noise ratio, mainly due to the synchrotron radiation (SR) background [6] produced in the upstream magnetic elements and the ambiguity in the determination of the beam size due to an offset of the particle trajectory in the slit with respect to the geometrical center, according to Eq.6 in Ref [2]. The last issue can be mitigated by using a complementary diagnostic able to track the beam trajectory inside the aperture.…”

Section: Introductionmentioning

confidence: 99%

Non-intercepting diagnostic for high brightness electron beams using Optical Diffraction Radiation Interference (ODRI)

Cianchi¹,

Balandin²,

Castellano³

et al. 2012

J. Phys.: Conf. Ser.

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First non-intercepting emittance measurement by means of optical diffraction radiation interference A Cianchi, V Balandin, M Castellano et al.-PIC code KARAT simulation of different types of polarization radiation generated by relativistic electron beam K P Artyomov, V V Ryzhov, G A Naumenko et al.-"Shadowing" of the electromagnetic field of relativistic charged particles G Naumenko, X Artru, A Potylitsyn et al. Abstract. High-gain Free Electron Lasers and future Linear Colliders require development of modern electron linacs with high brightness beams. Conventional intercepting transverse electron beam diagnostics, e.g. based on Optical Transition Radiation (OTR), cannot tolerate such high power beams without remarkable mechanical damages on the diagnostics device. Optical Diffraction Radiation (ODR) is an excellent candidate for measurements of the transverse phase space parameters in a non-intercepting way. One of the main problems of this method is the low signal to noise ratio, mainly due to the unavoidable synchrotron radiation background. This problem can be overcome by using two slits on metallic foils, placed at a distance shorter than the radiation formation zone. In this case a nearly backgroundfree ODR interference pattern is produced allowing the determination of the beam size and angular divergence. The accuracy on these parameters can be increased by exploiting both ODR polarization states, as well as different wavelengths. Here we report measurements of the ODR interference between two slits with different aperture sizes in a non-collinear geometry, carried out at FLASH (DESY, Germany). Our results demonstrate the unique potential of this technique to determine the beam parameters.

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Synchrotron radiation contributions to optical diffraction radiation measurements

Cited by 9 publications

References 9 publications

Nonintercepting electron beam size monitor using optical diffraction radiation interference

Nonintercepting electron beam size monitor using optical diffraction radiation interference

Noninvasive Micrometer-Scale Particle-Beam Size Measurement Using Optical Diffraction Radiation in the Ultraviolet Wavelength Range

Non-intercepting diagnostic for high brightness electron beams using Optical Diffraction Radiation Interference (ODRI)

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