Machine design and electron beam control of a single-pass linac for free electron laser : the FERMI@Elettra case study

In classical electromagnetism, a charged particle radiates energy in the form of electromagnetic radiation when it is subject to a force. This effect is the principle behind many useful sources of radiation such as electron synchrotrons and linear accelerators. The main figures of merit of synchrotron radiation sources are (narrow) spectral bandwidth, photon wavelength tunability and brilliance. The periodic motion of particles in a synchrotron makes these machines well-suited for a stable emission at high repetition rate. However, in addition to the synchrotron radiation and complementary to that, a strong need has emerged over the last few years for a source of radiation with extremely high brilliance, close to full coherence, a bandwidth approaching the Fourier limit and a stable and well characterized temporal structure in the femtosecond time domain. Such a source is the single-pass Free Electron Laser (FEL) that, due to Doppler frequency upshifting of emitted radiation by relativistic electrons, is particularly well-suited to generate short wavelength X-ray pulses with peak brilliance many orders of magnitude higher than that generated in modern synchrotrons and with subpicosecond pulse lengths. There are currently no alternative sources that have such high pulse energies and short durations. The investigation domain opened by the new FEL sources covers essentially all basic science fields giving access to explorations of matter in practically unexplored regimes. The scientific opportunities will in fact impact studies of a large number of disciplines encompassing material and biomaterial science, nanoscience, plasma physics, molecular and cluster femto- and nano- physics and chemistry, as well as having various connections to life, environmental, astrophysical and earth science. The FEL high brilliance, high intensity and shot-to-shot stability strongly depends on the electron beam source. Delivering a high quality electron beam and machine flexibility to serve a broad range of potential applications imposes severe requirements on the final electron beam parameters and the machine design. To meet these requirements, the need of a linac design based on extensive studies of possible perturbations that may affect the electron beam dynamics, of means to correct them and of parameter optimization has emerged.

High Energy & High Luminosity γγ\gamma\gamma Colliders

With the best of modern standard lasers, high-energy $\gamma\gamma$ colliders from electron beams of E larger than 250 GeV are only possible at the expense of photon luminosity, i.e. 10 times lower than for photon colliders at c.m. energies below 0.5 TeV. For existing state-of-the art lasers, an optimistic upper energy limit for x=4.8 is an electron beam of less than 250 GeV. This Snowmass21 Contributed Paper shows how Free Electron Lasers (FEL) pave the way for High Energy & High Luminosity $\gamma\gamma$ colliders. We present and assess a conceptual design study of a FEL with wavelength of 2.4 $\mu$m and an x-factor in the range of 2 to 40, to maximize the luminosity of a $\gamma\gamma$ collider as second interaction region of 0.5 TeV to 10 TeV c.m. $e^+e^-$ colliders.Comment: Contribution to Snowmass 202

Fish Skin Graft: Narrative Review and First Application for Abdominal Wall Dehiscence in Children

Summary: Acellular fish skin grafts (FSGs) are tissue-based products created by minimally processing the skin of the Atlantic cod (Gadus morhua). The FSG is rich in omega-3 and facilitates tissue regeneration by supporting revascularization and ingrowth in the proliferation and remodeling phases of wound healing. FSG is structurally more similar to human skin than antiviral-processed skin substitutes such as amniotic membrane, and there are no known prion, bacterial, or viral diseases that can be transmitted from North-Atlantic cod to humans. The FSG is processed using a proprietary method that preserves the structure and lipid composition of the skin. FSG is CE marked, and US Food and Drug Administration cleared for multiple clinical applications in partial and full-thickness wounds. FSG is currently the only acellular dermal matrix product that does not originate from mammalian tissues. For this narrative review, Medline and UpToDate were used to include a total of 21 articles published from 2015 to 2022 about fish skin graft use. We also reported a case of a 7-year-old boy who underwent treatment with FSG for abdominal wall dehiscence at our department of pediatric surgery, IRCCS Sant’Orsola- Malpighi, Alma Mater Studiorum, University of Bologna, University Hospital of Bologna. FSG provides a valuable and sustainable treatment that improves wound healing in both adult and pediatric populations. We described the first application of an FSG for wound dehiscence of the abdominal wall in a pediatric patient, reporting how FSG was completely reabsorbed and improved the skin’s repai

A case of massive subcutaneous emphysema and transient ischemic attack due to argon plasma coagulation following endoscopic pilonidal sinus treatment

Pilonidalsinusisasmallholeaffectingtheskinandsubcutaneoustissue,whichusuallycontainshairandskindebris,resultinginthecreationoftheso-calledpilonidalcyst.Theendoscopicpilonidalsinustreatment(EPSiT)isaminimallyinvasiveprocedureconsistingoftheremovalofhairsandcauterizationofthecavityunderdirectendoscopicvision.Inourinstitution,weusedtoendthisprocedurewithargonplasmacoagulation(APC).Here,wediscussacaseof22-year-oldmanaffectedbypilonidaldisease,whodevelopedamassivesubcutaneousemphysemaandsuspectedtransientischemicattacksecondarytogasreabsorptionafteranEPSiTinwhichAPCwassedforthecoagulation

Pelvic Health Assessment in Adult Females Following Pediatric Appendicitis: A Monocentric Retrospective Case—Control Study

open10noAbstract: Background: The anatomical location of the appendix in females determines its close contact with the internal genitalia, involving the latter in case of acute appendicitis (AA). The aim of this study was to evaluate the incidence of pelvic health impairment in adult women who underwent appendicectomy during childhood. Materials and Methods: A retrospective observational study was conducted including all female patients who underwent appendicectomy for acute appendicitis at our Center between January 1985 and December 1995. The patients were divided into two groups, i.e., complicated AA (Group A) and not complicated AA (Group B), and were asked to respond to a questionnaire investigating their general health status, fertility impairment, ectopic pregnancies, miscarriages, endometriosis, and chronic pelvic pain. The same questionnaire was administered to female volunteers with past medical history (PMH) negative for AA. The data were compared using chi-square test and Fisher exact test (a p value < 0.05 was considered for statistical significance). Results: In total, 75 patients operated for AA during childhood (22 in Group A and 53 in group B) and 44 female volunteers with PMH negative for AA (group C) were enrolled in the study. Seventeen patients (77.3%) in group A, 40 (75.4%) in group B, and 29 (65.9%) in group C (p > 0.05) had pregnancies. The number of miscarriages among women who became pregnant in their life was 5 in group A, 13 in group B, and 12 in group C (p > 0.05). Chronic pelvic pain was reported by 7 out of 22 (31.8%) patients in group A, 7 out of 53 (13.2%) in group B, and 5 out of 44 (11.4%) in group C (A vs. C: p = 0.04, OR = 3.64; A vs. B: p = 0.06 and B vs. C: p = 0.52). Conclusions: In our series, AA, complicated or not, neither determined repercussions on fertility, risk of miscarriages, and ectopic pregnancies nor increased the risk of developing endometriosis. However, women who experienced complicated AA showed a higher prevalence of chronic pelvic pain onset in adulthood compared to healthy women.openParente, Giovanni; Di Mitri, Marco; D’Antonio, Simone; Cravano, Sara; Thomas, Eduje; Vastano, Marzia; Lunca, Robert; Gargano, Tommaso; Libri, Michele; Lima, MarioParente, Giovanni; Di Mitri, Marco; D’Antonio, Simone; Cravano, Sara; Thomas, Eduje; Vastano, Marzia; Lunca, Robert; Gargano, Tommaso; Libri, Michele; Lima, Mari

Ask Doctor Smartphone! An App to Help Physicians Manage Foreign Body Ingestions in Children

Abstract: Background: Foreign body ingestion (FBI) represents the most common cause of emergent gastrointestinal endoscopy in children. FBI’s management can be quite challenging for physicians because of the variability of the clinical presentation, and the decision tree becomes even more intricate because of patient-specific variables that must be considered in the pediatric age range (e.g., age of patients and neuropsychiatric disorders) in addition to the mere characteristics of the foreign body. We present an application for smartphones designed for pediatricians and pediatric surgeons based on the latest guidelines from the official pediatric societies. The app aims to help physicians manage FBI quickly and properly in children. Materials and methods: The latest pediatric FBI management guidelines were reviewed and summarized. The flow chart we obtained guided the development of a smartphone application. A questionnaire was administered to all pediatric surgeon trainees at our institute to test the feasibility and helpfulness of the application. Results: An app for smartphones was obtained and shared for free on the Google Play Store and Apple Store. The app guides the physician step by step in the diagnostic process, analyzing all patient- and foreign body-specific characteristics. The app consultation ends with a suggestion of the most proper decision to make in terms of further radiological investigations and the indication and timing of endoscopy. A questionnaire administered to trainees proved the app to be useful and easy to use. Conclusion: We developed an app able to help pediatricians and pediatric surgeons manage FBI in children, providing standardized and updated recommendations in a smart and easily available way

Characterization of the transient response of diamond sensors to collimated, sub-ps, 1 GeV electron bunches

Diamond sensors (DS) are widely used as solid-state particle detectors, beam loss monitors, and dosimeters in high-radiation environments, e.g., particle colliders. We have calibrated our DS with steady β - and X-radiation, spanning a dose rate in the range 0.1-100 mGy/s. Here, we report the first systematic characterization of transient responses of DS to collimated, sub-picosecond, 1 GeV electron bunches. These bunches, possessing a charge ranging from tens to hundreds of pC and a size from tens of microns to millimeters, are suitably provided by the FERMI electron linac in Trieste, Italy. The high density of charge carriers generated by ionization in the diamond bulk causes a transient modification of electrical properties of DS (e.g., resistance), which in turn affects the signal shape. We have modeled a two-step numerical approach, simulating the effects on the signal of both the evolution of charge carrier density in the diamond bulk and the changes in the circuit parameters. This approach interprets features observed in our experimental results to a great extent

GeV-Class two-fold CW linac driven by an arc-compressor

We present a study of an innovative scheme to generate high repetition rate (MHz-class) GeV electron beams by adopting a two-pass two-way acceleration in a super-conducting Linac operated in Continuous Wave (CW) mode. The beam is accelerated twice in the Linac by being re-injected, after the first pass, in opposite direction of propagation. The task of recirculating the electron beam is performed by an arc compressor composed by 14 Double Bend Achromat (DBA). In this paper, we study the main issues of the two-fold acceleration scheme, the electron beam quality parameters preservation (emittance, energy spread), together with the bunch compression performance of the arc compressor, aiming to operate an X-ray Free Electron Laser. The requested power to supply the cryogenic plant and the RF sources is also significantly reduced w.r.t a conventional one-pass SC Linac for the same final energy