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An Electro-Optic Beam Position Monitor (EO-BPM) is being developed as a high-frequency (up to 10 GHz) diagnostic for crabbing and Head-Tail intra-bunch detection at the HL-LHC. Following an earlier prototype at the SPS that demonstrated single-pickup signals, an upgraded design of an interferometric EO-BPM has been beam-tested at the HiRadMat facility for validation and characterisation studies. In the new design, the fibre-coupled Mach-Zehnder interferometer arms are modulated by lithium niobate waveguides integrated in an upgraded opto-mechanical arrangement that has been developed to produce a highly magnified image field replica of the passing Coulomb field. A new detection technique that is directly sensitive to the interferometric optical difference signal from opposite EO buttons has been applied to measure single-shot bunches for the first time. A transverse resolution study over a ±20 mm range at 3 GHz bandwidth produced the first successful electro-optic bunch-by-bunch position measurement at the HiRadMat in-air extraction line. The results of this campaign show promise for an in-vacuum design that is in production for beam tests at the SPS during Run-3 of the LHC., Proceedings of the 11th International Beam Instrumentation Conference, IBIC2022, Kraków, Poland

A high bandwidth electro-optical beam position monitor is under development for the High Luminosity LHC. A series of measurements of the electro-optic signals were previously obtained by an EO-BPM prototype installed in the SPS. This paper focuses on an advanced design that would further improve the sensitivity of the pick-up by optimising the shape of the metallic electrode mounted onto the crystal. The proposed upgraded electro-optic pickups significantly increase the image field profile of the passing bunch inside a lithium niobate crystal embedded within the pickup. This work is based on parametric studies, performed using CST particle studio, investigating various electro-optic (electrode and crystal) configurations. We present the expected performance of the different designs, alongside with their evaluation on a test bench, highlighting the most relevant choice for a prototype pick-up to be installed on LHC, Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

Since 2016 a prototype electro-optic pickup has been installed on the SPS as part of the ongoing development of a high bandwidth electro-optic beam position monitor for the High Luminosity LHC. Following the success of initial beam signal observations with the prototype, improvements of the sensitivity and stability of the pickup have become the main focus of the project. A new concept has been developed which uses an interferometric technique to measure the image field of a passing bunch. One arm of an interferometer passes through an electro-optic lithium niobate crystal, embedded in a pickup, whereas the other arm bypasses. The recombination after the pickup results in an interference pattern that changes as a bunch passes by, due to the electro-optic response of the crystal to the image field. This technique enhances the sensitivity to the field and improves control of the working point. Results from high intensity beams at the SPS are presented. These include a comparison between two different interferometric configurations that were tested on different pickups with similar beam conditions. The stability is assessed by frequency scanning interferometry during beam operation., Proceedings of the 8th International Beam Instrumentation Conference, IBIC2019, Malmö, Sweden

An Electro-Optic Beam Position Monitor is being developed for the HL-LHC, aimed at the detection of high order proton bunch instabilities and as a diagnostic for crabbed bunch rotation. A prototype EO-BPM was installed in the CERN SPS during 2016 and recent first beam tests of the EO pick-up are presented. The tested system comprises two opposing pick-ups, each equipped with 5mm cubic LiNbO3 crystals in vacuum, illuminated by polarized light from a fibre-coupled CW 780 nm laser. The 1 ns proton bunch induces a temporal modulation in the polarization state of light emerging from each birefringent crystal, by the Pockels effect. The modulation is analyzed, then recorded by a fibre-coupled fast photodetector in the counting room. The very first experimental signals obtained by the EO-pickups of a passing proton bunch are reported as a proof of concept of the idea. Moreover, the expected response of the beam signal is measured with respect to remotely controlled changes in the polarizer and analyzer orientations. The data are compared with analytical and electromagnetic simulations. Following the first detection, we report the latest status of the prototype design and future prospects., Proceedings of the 6th Int. Beam Instrumentation Conf., IBIC2017, Grand Rapids, MI, USA

Bladder diverticula are herniations of the mucosa through the fibers of the bladder muscle connected by necks of variable amplitude. They are often asymptomatic, although they may lead to complications that require a surgical therapeutic approach. We report the case of a patient with bilateral obstructive uropathy secondary to a giant periureteral diverticulum that was treated by diverticulectomy and reimplantation of the left ureter in the bladder.