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In 2020-2022, extensive discussions and deliberations have taken place in corresponding topical working groups of the Snowmass Accelerator Frontier (AF) and in numerous joint meetings with other Frontiers, Snowmass-wide meetings, a series of Colloquium-style Agoras, cross-Frontier Forums on muon and electron-positron colliders and the collider Implementation Task Force (ITF). The outcomes of these activities are summarized in this Accelerator Frontier report., contribution to Snowmass'21, v.2 (final)

Background: Esophagectomy traditionally has high levels of perioperative morbidity and mortality due to the surgical techniques and case complexity. While thoracic epidural analgesia (TEA) is considered first-line for postoperative analgesia after esophagectomy, there can be complications related to its sympathectomy and mobility impairment. Additionally, it has been shown that postoperative outcomes are improved with early extubation following esophagectomy. Our aim is to describe the impact of transversus abdominus plane (TAP) blocks on extubation rates following esophagectomy when uncoupled from TEA. Methods: This is a retrospective study of 42 patients who underwent trans-hiatal esophagectomy between 2019 and 2022 who received a TAP block in the absence of TEA. The primary outcomes of interest were the rates of extubation within the operating room (OR) and reintubation. Secondary outcomes included: intensive care unit (ICU) and hospital length of stay (LOS), opioid pain medication use, time to enteral diet, reported postoperative pain scores, development of anastomotic leak, and 30-day readmission. Results: The mean age at operation was 63 years and 97.6% of patients were represented by American Society of Anesthesia (ASA) physical status class III or IV. 35 (83.3%) patients immediately extubated postoperatively. Nine patients (21.4%) underwent reintubation during their hospital course. Only six patients (14%) required vasopressors postoperatively. The median LOS was five days in the ICU and 10 days in the hospital. TAP block alone was found to be equivalent to TAP with additional regional blocks (TAP+) on the basis of immediate extubation, reintubation, ICU and hospital LOS, and reported postoperative pain. Conclusion: The results of this study demonstrate TAP blocks do provide comparable rates of successful immediate extubation and reintubation to TEA with fewer hypotensive complications after trans-hiatal esophagectomy. This was shown despite the elevated comorbidity burden of this study’s population. Additionally, TAP blocks maintained similar reported pain control scores to TEA literature.Overall, this study supports the use of TAP blocks as the primary analgesia in patients undergoing trans-hiatal esophagectomy over TEA. Trial Registration: This study includes participants who were retrospectively registered. IRB# 037.HPB.2018.R

The acceleration and storage of high energy polarized proton beams has made tremendous progress over the last 40 years challenging along the way the technologies, precision and the understanding of the beam dynamics of accelerators. This progress is most evident in that one can now contemplate high energy colliders with polarized beams and high luminosity at the same time. After a brief summary of the development and history of polarized proton beam acceleration this chapter will focus on the acceleration of polarized proton beams from MeV to the 100s of GeVs and the possibility of accelerating polarized beams to even higher energies in the future. Elements of the history of polarized electron beams, subject to the effects of synchrotron radiation, will be found in the electron beam polarization dedicated chapters in these lectures.

We discuss the goals, the designs, the state of technical readiness, and the critical R&D needs of the accelerators that are currently under discussion as Higgs and electroweak factories. We also address the respective staging options enabling future energy-frontier colliders. The accelerators covered are based on many different techniques and approaches. They include several circular colliders, various linear colliders, colliders based on energy recovery linacs (ERLs), ERL-ring combinations, as well as gamma-gamma colliders. The linear colliders proposed consist of options for the International Linear Collider (ILC), for the Compact Linear Collider (CLIC), for the Cold Copper Collider (C^3), and for the more recent Higgs-Energy Lepton Collider (HELEN). ERLs are key components of the Recycling Linear e+e- Collider (ReLiC), of the Energy Recovery Linear Collider (ERLC), and of the Circular Energy Recovery Collider (CERC). Among the more conventional ring colliders, the following proposals are featured: the Future Circular Collider (FCC-ee), the Circular Electron Positron Collider (CEPC), the Electron Positron Circular Collider at Fermilab (EPCCF), and the Large Electron Positron collider $\#$3 (LEP-3). In addition, we consider the X-ray FEL based gamma-gamma Collider Higgs Factory (XCC) and the High-Energy High-Luminosity gamma-gamma collider (HE&HL gamma-gamma). Finally, a Higgs factory based on a circular muon collider is mentioned for completeness., Submitted to Snowmass 2021

Colliders are essential research tools for particle physics. Numerous future collider proposal were discussed in the course of the US high energy physics community strategic planning exercise Snowmass'21. The Implementation Task Force (ITF) has been established to evaluate the proposed future accelerator projects for performance, technology readiness, schedule, cost, and environmental impact. Corresponding metrics has been developed for uniform comparison of the proposals ranging from Higgs/EW factories to multi-TeV lepton, hadron and ep collider facilities, based on traditional and advanced acceleration technologies. This article describes the metrics and approaches, and presents evaluations of future colliders performed by the ITF.

The Snowmass 2021 Implementation Task Force has been established to evaluate the proposed future accelerator projects for performance, technology readiness, schedule, cost, and environmental impact. Corresponding metrics has been developed for uniform comparison of the proposals ranging from Higgs/EW factories to multi-TeV lepton, hadron and ep collider facilities, based on traditional and advanced acceleration technologies. This report documents the metrics and processes, and presents evaluations of future colliders performed by Implementation Task Force., Comment: 68 pages; Submitted to the Proceedings of the US Community Study on the Future of Particle Physics (Snowmass 2021)

Continuous-wave photoinjectors operating at high accelerating gradients promise to revolutionize many areas of science and applications. They can establish the basis for a new generation of monochromatic x-ray free electron lasers, high-brightness hadron beams, or a new generation of microchip production. In this Letter we report on the record-performing superconducting rf electron gun with CsK_{2}Sb photocathode. The gun is generating high charge electron bunches (up to 10 nC/bunch) and low transverse emittances, while operating for months with a single photocathode. This achievement opens a new era in generating high-power beams with a very high average brightness.

We explore the possible use of particle beam storage rings as quantum computers. More precisely, we consider creating an ion trap system, in which the same computational basis states can be defined as in a modern ion trap system, but in which the ions have a constant velocity and are rotating in a circular trap. The basic structures that we explore are classical and ultracold crystalline beams. What we propose is a novel method that uses the ion trap quantum computer concept, but puts the ions into a rotating frame of reference. The benefits of this approach are discussed.

Energy recovery has been achieved in a multipass linear accelerator, demonstrating a technology for more compact particle accelerators operating at higher currents and reduced energy consumption. Energy delivered to the beam during the first four passes through the accelerating structure was recovered during four subsequent decelerating passes. High-energy efficiency was achieved by the use of superconducting accelerating cavities and permanent magnets. The fixed-field alternating-gradient optical system used for the return loop successfully transported electron bunches of 42, 78, 114, and 150 MeV in a common vacuum chamber. This new kind of accelerator, an eight-pass energy recovery linac, has the potential to accelerate much higher current than existing linear accelerators while maintaining small beam dimensions and consuming much less energy per electron.

The physics program at the future electron ion collider (EIC) calls for polarized neutron beams at high energies. The best neutron carriers are $^{3}\mathrm{He}$ nuclei and deuterons. Both neutron carriers are expected to be utilized by the spin physics program in the EIC. Owing to the small magnetic moment anomaly of a deuteron particle, significantly higher magnetic fields are required for spin rotation, so that full Siberian snakes are not feasible. However, the resonance strengths are weak, and the number of resonances is small. It is possible to deal with individual resonances using conventional methods such as a betatron tune jump and vertical ac dipole for intrinsic depolarizing resonances, and a weak partial snake for imperfection resonances. This study employed a realistic magnet ramp rate and parameters (both transverse and longitudinal emittances, as well as realistic lattices) to show that it is possible to accelerate polarized deuterons beyond 100 GeV/n. This paper summarizes the details of the feasibility of a polarized deuteron beam for the future EIC at Brookhaven National Laboratory.

Cooling of beams of gold ions using electron bunches accelerated with radio-frequency systems was recently experimentally demonstrated in the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. Such an approach is new and opens the possibility of using this technique at higher energies than possible with electrostatic acceleration of electron beams. The challenges of this approach include generation of electron beams suitable for cooling, delivery of electron bunches of the required quality to the cooling sections without degradation of beam angular divergence and energy spread, achieving the required small angles between electron and ion trajectories in the cooling sections, precise velocity matching between the two beams, high-current operation of the electron accelerator, as well as several physics effects related to bunched-beam cooling. Here we report on the first demonstration of cooling hadron beams using this new approach.

In polarized proton collision experiments, spin flip is needed to reduce the systematic errors. At high energy colliders with Siberian snakes, a single magnet spin flipper does not work . A more sophisticated spin flipper, constructed of nine-dipole magnets, was used to flip the spin in the BNL Relativistic Heavy Ion Collider. A 97% spin-flip efficiency was measured at both 24 and 255 GeV. The spin flip experiment results are presented in this paper.

In this letter we present a novel approach for a high-energy high-luminosity electron-positron collider. Present designs for high-energy electron-positron colliders are either based on two storage rings with 100 km circumference with a maximum CM energy of 365 GeV or two large linear accelerators with a high energy reach but lower luminosity, especially at the lower initial CM energies. A shortcoming of the collider based on storage rings is the high electric power consumption required to compensate for the beam energy losses from the 100 MW of synchrotron radiation power [1]. We propose to use an Energy Recovery Linac (ERL) located in the same-size 100 km tunnel to mitigate this drawback. We show in this letter that using an ERL would allow large reduction of the beam energy losses while providing higher luminosity in this high-energy collider operating at or above 140 GeV center-of-mass energy. Furthermore, our approach allows for extending the CM energy to 500 GeV, which would enable double-Higgs production, and even to 600 GeV for tt‾H production. Keywords: Double-Higgs production, Top Yukawa coupling, Next lepton collider, Energy recovery

In polarized proton collision experiments, it is highly advantageous to flip the spin of each bunch of protons during the stores to reduce the systematic errors. Experiments done at energies less than 2 GeV have demonstrated a spin-flip efficiency over 99%. At high energy colliders with Siberian snakes, a single magnet spin flipper does not work because of the large spin tune spread and the generation of multiple, overlapping resonances. A more sophisticated spin flipper, constructed of nine-dipole magnets, was used to flip the spin in the BNL Relativistic Heavy Ion Collider. A special optics choice was also used to make the spin tune spread very small. A 97% spin-flip efficiency was measured at both 24 and 255 GeV. These results show that efficient spin flipping can be achieved at high energies using a nine-magnet spin flipper.

El Plan de Seguimiento Individualizado (PSI) en salud mental nace de la necesidad de atender a las personas diagnosticadas de Trastorno Mental Severo que corren el riesgo de quedar desvinculadas del sistema asistencial. A través de diferentes mecanismos de actuación, el profesional que ocupa la labor del PSI, tendrá que delimitar las necesidades y capacidades de la persona que atiende, y además, coordinar acciones preventivas, de curación, rehabilitación y/ o soporte. Las dificultades psicosociales y/o ambientales que la enfermedad provoca, son muchas veces muy difíciles de gestionar, sumándole además el deterioro propio de la enfermedad. La figura de gestor de casos extrahospitalaria facilita poder trabajar todas las dificultades con las que la persona pueda encontrarse, haciendo de esta figura un pilar clave en la gestión diaria, pudiéndonos encontrar en este programa con objetivos muy diversos individualizados a cada persona. Una de las funciones más importantes que tenemos los profesionales de enfermería es promover el bienestar de la persona, aumentar su calidad de vida dando las curas necesarias adaptadas a cada situación de salud y de autonomía personal. Los profesionales, para poder conseguir este fin, tiene que analizar, priorizar, planificar y coordinar toda una serie de intervenciones para atender estos casos complejas, siendo básica la intervención desde diferentes ámbitos. La gran versatilidad de nuestro perfil profesional, y la capacidad de adaptación y flexibilidad que requiere este trabajo, hacen que podamos poner en práctica muchas de las competencias enfermeras. Descripció del recurs: 2 de setembre de 2022 DDEUIT

The proposed electron-hadron collider (eRHIC) to be built at Brookhaven National Laboratory (BNL) will allow the collisions of 20 GeV polarized electrons with 250 GeV polarized protons, or $100\text{ }\mathrm{GeV}/\mathrm{n}$ polarized ${^{3}\mathrm{He}}^{+2}$ ions, or other unpolarized ion species. The large value of the anomalous magnetic moment of the $^{3}\mathrm{He}$ nucleus ${G}_{\mathrm{He}}=(g\ensuremath{-}2)/2=\ensuremath{-}4.184$ (where $g$ is the $g$-factor of the $^{3}\mathrm{He}$ nuclear spin) combined with the peculiar layout of the transfer line which transports the beam bunches from the Alternate Gradient Synchrotron (AGS) to the Relativistic Heavy Ion Collider (RHIC) makes the transfer and injection of polarized $^{3}\mathrm{He}$ ions from AGS to RHIC (AtR) a special case as we explain in the paper. Specifically in this paper we calculate the stable spin direction of a polarized $^{3}\mathrm{He}$ beam at the exit of the AtR line which is also the injection point of RHIC, and we discuss a simple modifications of the AtR beam-transfer-line, to perfectly match the stable spin direction of the injected polarized $^{3}\mathrm{He}$ beam to that of the circulating beam, at the injection point of RHIC.

We expand upon the idea of using gamma-rays for nuclear photoflssion of 238U at the giant dipole resonance to generate rare neutron-reach nuclei. The SPIRAL II project proposes the employment of 10-20-MeV Bremsstrahlung gamma-rays generated by a 45-MeV electron beam /http://ganinfo.in2p3.fr/research/ developments/ spiral2/ index.html/. In this paper, we explore the possibility of using a Compton gamma-ray source for such a process. The Collider Accelerator Department at Brookhaven National Laboratory is developing high-current (up to 1 A), high-brightness (down to 1-mm ldr mrad normalized emittance), and high-energy energy-recovery linacs (up to 20-GeV electron beam energy for eRHIC). These electron beams are perfectly suited for generating photon beams with tremendous average power, approaching the megawatt level. The range of photon's energy extends from subelectronvolts from free-electron lasers to 10 GeV from the Compton process. In this paper, we focus on a gamma-ray source for producing rare isotopes.

High-gradient CW photo-injectors operating at high accelerating gradients promise to revolutionize many sciences and applications. They can establish the basis for super-bright monochromatic X-ray free-electron lasers, super-bright hadron beams, nuclear- waste transmutation or a new generation of microchip production. In this letter we report on our operation of a superconducting RF electron gun with a record-high accelerating gradient at the CsK2Sb photocathode (i.e. ~ 20 MV/m) generating a record-high bunch charge (i.e., 3 nC). We briefly describe the system and then detail our experimental results. This achievement opens new era in generating high-power electron beams with a very high brightness., 13 pager, 5 figures

The Cornell-BNL FFAG-ERL Test Accelerator (C$\beta$) will comprise the first ever Energy Recovery Linac (ERL) based on a Fixed Field Alternating Gradient (FFAG) lattice. In particular, we plan to use a Non Scaling FFAG (NS-FFAG) lattice that is very compact and thus space- and cost- effective, enabling multiple passes of the electron beam in a single recirculation beam line, using the superconducting RF (SRF) linac multiple times. The FFAG-ERL moves the cost optimized linac and recirculation lattice to a dramatically better optimum. The prime accelerator science motivation for C$\beta$ is proving that the FFAG-ERL concept works. This is an important milestone for the Brookhaven National Laboratory (BNL) plans to build a major Nuclear Physics facility, eRHIC, based on producing 21 GeV electron beams to collide with the RHIC ion beams. A consequence of the C$\beta$ work would be the availability of significantly better, cost-effective, compact CW high-brightness electron beams for a plethora of scientific investigations and applications, such as X-ray sources, dark-matter and dark-energy searches, and industrial high-power Free-Electron Laser (FEL) applications. C$\beta$ brings together the resources and expertise of a large DOE National Laboratory, BNL, and a leading research university, Cornell. C$\beta$ will be built in an existing building at Cornell, for the most part using components that have been developed under previous R&D programs, including a fully commissioned world-leading photoemission electron injector, a large SRF accelerator module, and a high-power beam stop. The only elements that require design and construction from scratch is the FFAG magnet transport lattice. This white paper describes a project that promises to propel high-power, high-brightness electron beam science and applications to an exciting new level., Comment: White paper dated December 16, 2014. 16 pages, 8 figures

Horizontal beam orbit jitter at frequencies around 10 Hz has been observed at RHIC for several years. The distinct frequencies of this jitter have been found at superconducting low-beta quadrupole triplet magnets around the ring, where they coincide with mechanical vibration modes of the cold masses. Recently, we have identified liquid helium flow as the driving force of these oscillations.

A five-cell high current superconducting cavity for the electron cooling project at RHIC has been designed. The 703.75 MHz cavity and cryomodule is under fabrication and nearing completion. The different components of the cryomodule and the status of their fabrication is discussed.

A wide range of optics issues for energy recovery linac (ERL)-based projects are illustrated through the presentation of ongoing projects covering both light sources, at Cornell and Daresbury and high energy and nuclear physics accelerators at the Brookhaven National Laboratory. This presented range of projects demonstrates how the different designs teams see the challenges of studying and solving optics issues for their particular project's ERLs, with studies appropriate to the stage of maturity of the project. Finally, as an illustration of the complexity and detail behind a single aspect of ERL optics design we present an overview of the highly important generic topic of longitudinal phase space evolution in ERLs.

A new normal conducting snake magnet is being fabricated for the alternate gradient synchrotron (AGS) at Brookhaven National Laboratory (BNL). In the Relativistic Heavy Ion Collider (RHIC) project, a superconducting type helical dipole magnets had been developed and it performed successfully in high-energy polarized proton acceleration. The new AGS helical snake has the same basic magnetic structure but is more complicated. To achieve no beam shift and no beam deflection in one magnetic device, helical pitches and rotating angles were carefully calculated. Compared to a superconducting magnet, a normal warm magnet must have a large cross-sectional area of conductors which make it difficult to design a magnet with large helical pitch. We developed a modified window frame structure to accommodate the large number of conductors. Its three dimensional magnetic field was simulated by using OPERA3D/TOSCA.

This section describes both: successful commissioning of RHIC and the state of the art RHIC accelerator physics tools/applications. The commissioning provided collisions of the fully stripped gold ions at a beam energy of 65 GeV/nucleon in all four experiments “STAR”, “PHENIX”, “PHOBOS”, and “BRAHMS”. They collected more than 3 μb −1 of data. Measurements of betatron and dispersion functions have shown excellent agreement with predictions. Diagnostic results from tune-meter, wall current monitor, chromaticity, decoupling measurements, ionization beam profile monitor, Schottky monitors, etc. are shown. Progress towards stable gold ion beam stores with optimized luminosity is described [Proceedings of the HEACC2001 The 18th International Conference On High Energy Accelerators, March 26–30, 2001, Tsukuba, Japan, March, 2001]. Few major commissioning challenges are described first. The most important results, from some of the RHIC systems, are shown in the next section. In the following section bringing beams from two separate “blue” and “yellow” rings into collisions and measurements during long beam stores are described. In the summary part necessary steps and commissioning of additional systems during the next RHIC-2001 run are mentioned.