Local discrimination of orbital angular momentum in entangled states

We address the use of a calcite crystal-based local detector to the discrimination of orbital angular momentum of quantum radiation produced by parametric down conversion. We demonstrate that a discrimination can be obtained exploiting the introduction of a fine and controlled spatial shift between two replicas of the state in the crystals. We believe that this technology could be used for future development of long-distance quantum communication techniques, where information encoding is based on orbital angular momentum

CERN’s beam instrumentation R&D study for FCC-ee

The Future Circular Collider (FCC) R&D study was started in 2021 as a comprehensive feasibility analysis of CERN’s future accelerator project encompassing technical, administrative and financial aspects. As part of the study, Beam Instrumentation (BI) is a key technical infrastructure that will have to face unprecedented challenges. In the case of electron-positron FCC-ee, these are represented, among others, by the size of the accelerator, the amount of radiation produced along the ring and in machine-detector interaction region, the presence of the top-up booster and collider ring in the same tunnel. In this contribution we will present the current FCC-ee BI study and discuss its status and perspectives

Exploring services provided by top Italian museums websites:What are they used for?

Even though a number of studies have focused on museum websites, specific studies about top Italian museums and the services provided online have not been found. This paper aims to fill this gap in the literature and investigate the online services performed by top Italian museums. The objective is to determine whether these museums have developed their own website, and what kind of services they provide to their online visitors. The presence or lack of services provided was recorded with the adoption of a descriptive approach, based on qualitative content analysis principles. Results are shown in terms of three kinds of services provided (virtual visit opportunities, e-commerce services, and e-relation tools). Results provide managers a mapping of the services provided by their specific museum. Nevertheless, they need to be expanded with further primary research

Electron Beam Size Measurements Using the Heterodyne Near Field Speckles at ALBA

Experiments using the heterodyne near field speckle method (HNFS) have been performed at ALBA to characterize the spatial coherence of the synchrotron radiation, with the ultimate goal of measuring both the horizontal and vertical electron beam sizes. The HNFS technique consists on the analysis of the interference between the radiation scattered by a colloidal suspension of nanoparticles and the synchrotron radiation, which in this case corresponds to the hard x-rays (12keV) produced by the in-vacuum undulator of the NCD-Sweet beamline. This paper describes the fundamentals of the technique, possible limitations, and shows the first experimental results changing the beam coupling of the storage ring

Progress on Transverse Beam Profile Measurement Using the Heterodyne Near Field Speckles Method at ALBA

We present the recent developments of a study aiming at measuring the transverse beam profile using the Heterodyne Near Field Speckles (HNFS) method. The HNFS technique consists of a suspension of nanoparticles suspended in a liquid and illuminated by synchrotron radiation (either in the visible or in X-ray wavelength range). The transverse coherence of the source, and therefore, under the conditions of validity of the Van Cittert and Zernike theorem, the transverse electron beam size is retrieved from the interference between the transmitted beam and the spherical waves scattered by each nanoparticle. We here describe the fundamentals of this technique, as well as the recent experimental results obtained with 12 keV radiation at the NCD beamline at ALBA. The applicability of such technique for future accelerators (e.g. CLIC or FCC) is also discussed

Transverse Beam Size Diagnostics using Brownian Nanoparticles at ALBA

In this work we describe a novel beam diagnostic method based on coherence characterization of broad-spectrum bending magnet radiation through the Heterodyne Near Field Scattering (HNFS) technique. HNFS is a self- referencing technique based on the interference between the transmitted beam and the spherical waves scattered by each particle of a colloidal suspension. The resulting single-particle interferogram shows circular interference fringes modulated by the spatio-temporal Complex Coherence Factor (CCF) of the radiation. Superposition of a number of these patterns results in a stochastic speckle field, from which spatial and temporal coherence information can be retrieved in near field conditions. Here we describe the basics of this technique, the experimental setup mounted along the hard X-ray pinhole at the ALBA synchrotron light source, and the possibility of transverse electron beam size retrieval from the spatial coherence function of the emitted dipole radiation. We also show preliminary results concern- ing power spectral density of visible synchrotron radiation as obtained from temporal coherence

FOCUS: Fast Monte-CarlO Approach to Coherence of Undulator Sources

We present Fast Monte-CarlO approach to Coherence of Undulator Sources (FOCUS), a new GPU-based code to compute the transverse coherence of X-ray radiation from undulator sources. The code relies on scaled dimension- less quantities and analytic expressions of the electric field emitted by electrons in an undulator. A consistent use of Fourier optics and statistical optics naturally leads to the core structure of the code, which exploits GPUs for massively parallel computations. We validate our approach by direct comparison with Synchrotron Radiation Workshop (SRW), evidencing a reduction in computation times by up to five orders of magnitude on a consumer laptop. Finally, we show examples of applications to beam size diagnostics

Simulation Methods for Transverse Beam Size Measurements Using the Heterodyne Near Field Speckles of Hard X-rays

The Heterodyne Near Field Speckles (HNFS) is a special type of interferometry technique where radiation is scattered by nanoparticles suspended in a medium. The scattered waves and the transmitted radiation form an interference pattern, which is modulated by the spatial coherence of the radiation and by the scattering properties of the nanoparticles. The superposition of many such interference patterns results in a speckle pattern, from which the spatial coherence of the radiation and thus the transverse beam profile can be determined. In this contribution we present approaches for simulating the HNFS patterns from hard X-ray radiation and compare then with data from experiments at the ALBA synchrotron

Beam Instrumentation Challenges for FCC-ee

For the accelerator-based future of high energy physics at the energy frontier, CERN started to investigate a 92 km circumference Future Circular Collider (FCC), as e⁺/e⁻ collider the FCC-ee will operate at beam energies up to 182.5 GeV. Beside the machine operational aspects, beam instrumentation will play a key role in verifying and optimizing the machine to achieve the ambitious beam parameters and quality. This paper gives a brief overview of the various challenges to develop the required beam instruments, with focus on beam position, beam size and bunch length measurements, and well as an outline of the planned R&D; activities

Two-Dimensional Beam Size Measurements with X-Ray Heterodyne Near Field Speckles

We report on 2D beam size measurements with a novel interferometric technique named Heterodyne Near Field Speckles, capable of resolving few-micrometer beam sizes. It relies on the interference between the weak spherical waves scattered by a colloidal suspension and the intense transilluminating X-ray beam. Fourier analysis of the resulting speckles enables full 2D coherence mapping of the incoming radiation, from which the beam sizes along the two orthogonal directions are retrieved. We show experimental results obtained with 12.4 keV X-rays at the NCD-SWEET undulator beamline at ALBA, where the vertical beam size has been changed between 5 and 15 micrometers by varying the beam coupling. The results agree well with the estimated beam sizes from the pinhole calculations. Finally, we discuss recent investigations on alternative targets aimed at improving the signal-to-noise ratio of the technique