bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Beam Orbit Shift due to Synchrotron Radiation
Authors: Wang C H , Lan J K , Zhouf T Y , Sun B G
Published: January 2024

The beam orbit stability is the crucial indicator to evaluate the performance of the synchrotron radiation source. In order to obtain higher beam quality, higher stability requirements are placed on the beam orbit. The stability can be improved through accurate measurement of beam orbit by beam position monitors (BPMs) and appropriate feedback system. However, due to radiation of the synchrotron beams on the vacuum chamber, the thermal effect of synchrotron radiation causes the thermal deformation of the vacuum chamber. The thermal deformation drives the BPM fixed on the vacuum chamber to move, which will induce error to the beam orbit. We analyze the effect of beam current on the vacuum chamber movement and the effect of vacuum chamber movement on the beam orbit. We also built an online vacuum chamber displacement measurement system on Hefei Light Source II (HLS II), which is used to validate and correct our analysis. After analysis and verification, the vacuum chamber moves with the change of current. The larger the change of current, the larger the vacuum chamber displacement. The vacuum chamber displacement has a hysteresis compared to the current change.
A compact dielectric grating-based charged particle bunch length diagnostic device at ARES
Authors: Stacey B , Assmann R , Hillert W , Kuropka W , Vinatier T
Published: January 2024

Dielectric gratings are already used in Dielectric Laser Acceleration due to their high damage thresholds at high acceleration gradients. When an electron bunch passes close to one of these gratings, it emits radiation, and the features of this radiation will be dependent upon the beam position relative to the grating, the bunch charge, and the bunch length. A compact high-resolution diagnostics device will be developed that consists of multiple gratings with different periods; these types of devices are required for the accurate operation of future compact accelerators which are currently undergoing development and testing. ARES linac at DESY is able to provide sub-fs electron bunches and has a range of high-resolution diagnostic devices installed, such as the PolariX Transverse Deflecting Structure, which will allow for performance verification of a new diagnostic. The electron bunches can be altered, allowing for the measurement and analysis of the emitted radiation for different bunch lengths and charges. This work will present the current progress in this area, including the presentation and discussion of simulations, and a discussion of the planned experiments at ARES.
Study on beam position measurement based on diode detection in HLS-II
Authors: Lan J K , Wang C H , Zhouf T Y , Sun B G
Published: January 2024

In order to improve the sensitivity and long-term stability of beam position measurement for Hefei Light Source – II (HLS-II), it is necessary to improve the measurement method. The beam position monitor (BPM) electronics is used to measure the beam position and is an important part of the beam position measurement system. In this paper, a beam position measurement system based on the compensated diode detection (CDD) technology for electron storage ring was proposed. Since HALF under construction, the parameters of HLS-II were used to design the system and simulate the system circuits to verify its feasibility.
Design Aspects of the Emittance Diagnostic for the Scorpius Accelerator
Authors: Raphaelian M.L. , Dzenitis D.M. , Littleton S.T. , Mazotti A.A. , Weber F.A. , Pogue N.J. , Duffy P. , Falabella S. , Stem W.D.
Published: January 2024

A multi-pulse linear induction accelerator, Scorpius, will be constructed at the NNSS U1A facility for use in radiographic experiments. One of the many diagnostics, the injector emittance diagnostic, will provide information on the quality of the beam emanating from the injector and therefore the quality of the beam in the accelerator. A slit-harp design was chosen for the emittance diagnostic. We have modeled the performance of the diagnostic for various simulated Scorpius beams, using several computational tools depending on the physics of the effects under investigation. Additional modeling of electron stopping power, energy deposition, heat dissipation, and x-ray attenuation drove material choices for the collimator jaws and harp wires. The signal chain is designed around constraints of signal extraction, biasing to suppress crosstalk between harp wires via secondary electron emission, and multi-pulse record capability. The ensemble of materials, electrical, and mechanical aspects of the design to reconstruct the emittance from the injector of the accelerator are described.
TPS Fast Orbit Feedback Upgrade
Authors: Chiu P. C. , Huang C. H. , Wu C. Y. , Hsu K.T. , Liao C.Y. , Cheng Y.S. , Hu K.H.
Published: January 2024

The orbit feedback system for the Taiwan Photon Source (TPS) was delivered in 2014. With the installation of an increasing number of insertion devices, a variety of wide-band disturbances are produced. In 2019, a proposal was put forth to enhance the stability of the orbit through the implementation of the fast orbit feedback (FOFB) system upgrade. The upgrade plan encompasses the revision of the power supply controller and an increase in the feedback computation rate from 10 kHz to 30 kHz. Following the upgrade, the bandwidth of the TPS fast orbit feedback system has been expanded from 250 Hz to 400 Hz in the vertical plane and from 200 Hz to 250 Hz in the horizontal plane. The integrated power spectrum density of the orbit could be reduced by approximately 20% with effective measures.
Status and upgrade of the visible light diagnostics port for energy spread measurements at KARA
Authors: Patil M. M. , Bründermann E. , Caselle M. , Funkner S. , Goffing C. , Niehues G. , Steinmann J. L. , Widmann C. , Müller A.-S. , Centis Vignali M. , Boscardin M. , Paternoster G.
Published: January 2024

At the visible light diagnostic (VLD) port at the Karlsruhe Research Accelerator (KARA), it is possible to study the energy spread of electron bunches by measuring the horizontal bunch profile of the incoherent synchrotron radiation. KALYPSO, an MHz-rate line-array detector, has been employed to measure the bunch profile. Recently, the KALYPSO system has been upgraded to a version of a microstrip sensor based on TI-LGAD. The measurements have shown that the system’s overall sensitivity was significant - at least by a factor of 20 improved, enabling the study of bunch profiles at low bunch charges. This contribution will present an overview of the upgraded setup and preliminary results.
New controls for White Circuits power supplies for the booster synchrotron of Taiwan light source
Authors: Liao C Y , Wu C Y , Cheng Y S , Chen J , Lee D , Hu K H , Hsu K T
Published: January 2024

The controls of the White Circuits for the booster synchrotron of Taiwan Light Source (TLS) were developed in the late 1990s. That design is based on various analog circuitry to detect 10 Hz magnet amplitude and phase. The existing implementation consists of analog regulation for amplitude control and digital regulation for the relative phase between magnet families. Recently, modernized White Circuits controls were implemented to prevent component obsolescence in the existing system. The upgraded system adopts digital regulation for both amplitude and phase loops. Improve performance and easy maintenance are the goals of this upgrade.
Development of a new control interface for the electron gun pulser of TLS Linac
Authors: Liao J K , Lee D , Cheng Y S , Wu C Y , Hu K H , Hsu K T
Published: January 2024

The electron gun control system, which serves as the TLS LINAC’s power source, has been in operation for more than two decades. Since some components of a previously designed circuit have aged and been discontinued, the control system will become unreliable and irreparable. A new control interface of electron gun pulser has been developed to improve the operational stability and future maintenance of the electron gun control system. To achieve remote control, an SBC (single-board computer) equipped with a high-precision AD/DA expansion board was used as a control interface. The signal processing circuit module generates the bias and b-plus voltages that are output to the electron gun and also provides instant feedback voltage readings. For easier maintenance, the new electron gun pulser control modules have been assembled into a single box. Furthermore, this software architecture of control interface has been based on the EPICS framework and integrated with an existing TLS control system. The efforts of rejuvenating electron gun pulser control system are described in this paper.
Stability analysis of double-harmonic cavity system in heavy beam loading with its feedback loops by a mathematical method based on Pedersen model
Authors: Shen Y B , Gu Q , Jiang Z G , Gu D , Zhu Z H
Published: January 2024

With the high beam current in storage ring, it is necessary to consider the instability problem caused by the heavy beam loading effect. It has been demonstrated that direct RF feedback (DRFB), autolevel control loop (ALC) and phase-lock loop (PLL) in the main cavity can lessen the impact of the beam effect. This paper regarded the beam, main cavity, harmonic cavity and feedback loops as double harmonic cavity system, and extended the transfer functions in the Pedersen model to this system. Some quantitative evaluations of simulation results have been got and conclusions have been drawn. In the case of a passive harmonic cavity, the optimization strategy of the controller parameters in the pre-detuning, ALC and PLL, as well as the gain and phase shift of DRFB were discussed. Meanwhile, it also involved the impact of the harmonic cavity feedback loop on the system stability at the optimum stretching condition when an active harmonic cavity was present. The research results can be used as guidelines for beam operation with beam current increasing in the future.
Test stand for conditioning high power tetrodes at TRIUMF
Authors: Avreline N V , Zvyagintsev V , Gregoire D , Piletskiy K
Published: January 2024

A major part of the 520 MeV Cyclotron’s RF system is the high-power RF amplifier. The amplifier is based on eight 4CW250,000B tetrodes. A new high-power tetrode or a high-power tetrode that underwent refurbishing could trip the RF system through inner sparks. The likelihood of those sparks should be reduced prior to applying nominal power to the new and refurbished tetrodes. This could be achieved by RF conditioning of these tetrodes on a test stand. The test stand represents a 150 kW RF amplifier loaded by a dummy load. The amplifier is built using common grid schematics. The test stand’s output stage incorporates the 4CW250,000B tetrode that is under test. This paper describes the mechanical and electrical designs of the test stand, procedures of testing and conditioning for 4CW250,000B tetrodes, and the results of test stand’s commissioning.
Bimodal design of 500MHz and 1.5GHz normal conducting RF cavity for advanced synchrotron radiation facilities
Authors: Su Dinghui , Tan Janhao , Fang Wangcheng , Wang Cheng
Published: January 2024

The advanced storage ring light source needs to realize ultra-low emissivity beam operation, and improving the Touschek lifetime puts forward higher requirements for the performance of RF cavity. In this paper, a novel bimodal normal conducting RF cavity is proposed. In one cavity, two power sources will be connected at the same time to realize the simultaneous operation of the two frequencies. The TM010 mode with the frequency of 500 MHz is used for acceleration, and the TM020 mode with the frequency of 1.5 GHz is used as the third harmonic to improve the height of the RF bucket and achieve the purpose of lengthening the beam bunch. Two couplers are designed to adapt to the working characteristics of bimodal RF cavity.
Magnetic Alloy Core Loaded 2nd harmonic cavity design and testing for CSNS-II RCS
Authors: Wu Bin , Li Xiao , Nie Xiao Jun , Zhang Chun lin , Liu Yang , Long Wei , Li Xiang , Wu Jian
Published: January 2024

In this report, we present our recent progress in the design and high-power testing of the 2nd harmonic cavity for the China Spallation Neutron Source upgrade project. To achieve optimal performance, high-performance magnetic alloy (MA) cores with dimensions of Φ850mm × Φ316mm × 25mm were meticulously developed and fabricated to serve as the load material for the radio-frequency (RF) cavity. Through rigorous testing, we were able to achieve a remarkable cavity accelerating gradient of over 40 kV/m under 15% duty cycle. To ensure optimal cooling efficiency, we conducted a comprehensive fluid dynamics simulation analysis and verified our results through experiments. Finally, to assess the long-term stability and performance of the cavity, we conducted a series of extended operation tests. These experiments successfully confirmed the high-performance capabilities and exceptional stability of the 2nd harmonic cavity.
Improved waveforms for Barrier-Bucket systems
Authors: Breitkreutz B , Stassen R
Published: January 2024

Barrier-Bucket (BB) systems provide a method to apply a short gap to a coasting beam. This is utilized for different applications, like ion cleaning, or to compensate the medium energy loss caused by internal experiments. BB-cavities are broadband cavities, and the applied signal is commonly a short sine burst, followed by a flat section at zero voltage. Since the transfer function of the BB-system is usually neither flat nor linear, it is common to predistort the signal to obtain the desired shape at the rf gap. Nevertheless, the resulting waveform still has a ripple in the flat section. This is due to the lowpass characteristic of the amplifier and the sharp edges at the ends of the sine, which lead to an infinite number of harmonics. This paper provides better suited BB-waveforms, which are designed with a finite number of harmonics from the beginning. It is shown that a much better flatness can be achieved than for a conventional BB-waveform, without sacrificing any performance. These advanced waveforms are currently used at the hadron synchrotron COSY at Forschungszentrum Jülich, leading to improved BB-bunch shapes, in particular for electron-cooled beams.
Electrodeposition of copper on niobium for cryocooler application
Authors: Prudnikava A. , Tamashevich Y. , Kugeler O. , Knobloch J.
Published: January 2024

The electrodeposition of copper onto niobium using commercial acidic and alkaline electrolytes was tested. The continuous dense polycrystalline copper films were successfully obtained in aqueous alkaline-type bath containing copper sulphate, sodium hydroxide and sodium gluconate. The effect of benzotriazole and sodium lauryl sulphate additives on the morphology and crystal structure of the deposited copper was investigated by optical and scanning electron microscopy, and X-ray diffraction. No copper oxides were found in the grown films. Copper films had moderate adhesion properties that would be insufficient for cryocooler application. We are currently exploring different compositions of electrolyte baths for obtaining the coatings on niobium with improved adhesion.
Status and upgrades of radio frequency system at Taiwan Photon Source
Authors: Chang M H , Lo C H , Yu T C , Liu Z K , Chung F T , Chang F Y , Chang S W , Chen L J , Li Y T , Yeh M S , Wang Ch , Lin M C
Published: January 2024

In order to meet the upcoming RF power requirements of TPS, a five-year upgrade project to construct a new RF station was completed in early 2022. This new RF station mainly consists of an SRF module, a 300-kW SSPA, an analog LLRF control system, RF transmission components, and accessary cooling systems. Test results of the SRF module and 300-kW SSPA met the expected performances. Also presented are the operation statistics of the two original RF stations and the ongoing upgrades. Meantime between RF failures during TPS user time reached 600 hours in 2022, while the construction and tests on DLLRF control system, power combination of klystron and SSPA, and 2-cell 1.5-GHz SRF module have all progressed well.
Conceptual design of multipole injection kicker magnets for the ILSF storage ring
Authors: Azami Z , Saeidi F , Tafrihi A , Ahmadi E , Noori K
Published: January 2024

The standard injection scheme of the Iranian Light Source Facility(ILSF) is composed of 2 septum and 4 kicker magnets installed in a 7-meter-long straight section. Further tuning of the 4 kicker devices to reduce perturbations has proven to be almost impossible since it requires having 4 identical magnets, electronics and Ti-coated ceramic chambers. Different from pulsed dipole kicker magnets used in a conventional local-bump injection, a single nonlinear or multipole kicker provides a nonlinear distribution of magnetic fields, which has a maximum value off the axis where the injected beam arrives and a zero or near-zero value at the center where the stored beam passes by. So, here the designs of different multipole kickers, including sextupole, octupole and a nonlinear kicker, have been investigated and compared.
Development of a New Electromagnetic Extraction Channel from the AGOR Cyclotron
Authors: Kremers H R , Jones B N , Smit H A J , Gerbershagen A , Brandenburg S
Published: January 2024

The extraction system of the superconducting AGOR cyclotron consists of an electrostatic deflector and three electromagnetic channels. As the electrostatic deflector has only a moderate field strength (<100 kV/cm), the first electromagnetic channel (EMC1) has to generate a rather strong dipole component resulting in current densities up to 169 A/mm2 in water-cooled copper coils. In the original design the coils consist of sections of hollow conductors, parallel to the beam path, vacuum-brazed to machined “bridges” over the beam aperture. Altogether there are over 200 brazed joints made in three subsequent cycles in the three coils (dipole, quadrupole and first harmonic corrector). In 25 years of operation two channels of this type have been “consumed”. The channels developed water leaks due to erosion of the copper by the high speed cooling water flow in the “bridge” regions that ultimately could not be repaired anymore. To remedy this problem the channel has been redesigned using bent conductors. A production technique for small radius bends and a new joining method to avoid vacuum brazing have been developed. The coil support taking up the 10 kN/m Lorentz forces on the windings are now made from isolating material instead of anodized aluminium to prevent grounding errors. The new channel (EMC1-U) has been in operation now for two years without any failure. A detailed comparison of the old and new design will be presented.
High-Power Modular GaN Based Power Supply for MedAustron Scanning Magnets
Authors: Margreiter T , Gadner T , Incurvati M , Teixeira R A , Cesaris I De , Pelletier S
Published: January 2024

MedAustron is a synchrotron-based ion therapy center in Wiener Neustadt, Austria, constantly working towards the performance improvement of cancer treatment. A major improvement opportunity comes from the scanning magnets system – a crucial element of dose delivery system at MedAustron - that is influenced by the bandwidth and power density of the magnet power supplies. Therefore, a novel highly modular power converter, based on the latest gallium nitride technology is being developed to tackle the aforementioned requirements. One sub-module of this power supply is based on two H-bridges that are operated in hard parallel and are integrated into a standardized euro-crate form factor with target output power specifications of 720 kW. This design also includes a 4th-order output Bessel filter to meet the ripple requirements for clinical operation. Furthermore, those sub-modules offer the possibility of being connected, cascaded or interleaved, in order to meet different output power requirements, providing a high modularity aspect. The status of this development in terms of requirements, global topology, and control structure is presented.
Measurement of the Photoelectron Yield from the Synchrotron Radiation for the NEG-coated Tubes
Authors: Hsiung G Y , Cheng C M , Valizadeh R
Published: January 2024

NEG-coated chambers have been adopted as the beam ducts for large particle accelerators and synchrotron light sources for the sake of the lower yields of the photon stimulated desorption (PSD) and the photoelectrons (PE) from the NEG films in addition to their pumping performance. Measurement of the photoelectron yield (PEY) was performed at the BL19B (PSD) beamline of the 1.5 GeV Taiwan Light Source (TLS) which simultaneously measures the PSD-yield. An aluminium cathode was inserted in the tubes and a positive bias of voltage for extraction of the photoelectrons applied. The PEY was obtained by dividing the photoelectron current by the photon flux of the synchrotron radiation. Measurements of the PEY include various types of NEG-coated stainless steel tubes and the bare tubes of titanium and aluminium alloys for the comparison. The experimental system and the results will be described in this presentation.
RF Characterisation of Laser Treated Copper Surfaces for the Mitigation of Electron Cloud in Accelerators
Authors: Krkotić P , Calatroni S , Himmerlich M , Neupert H , Perez-Fontenla A T , Wackerow S , Abdolvand A
Published: January 2024

In accelerator beam chambers and RF waveguides, electron cloud and multipacting can be mitigated effectively by reducing the secondary electron yield (SEY). In recent years, it has been established that laser-engineered surface structuring is a very efficient method to create a copper surface with a SEY maximum close to or even below unity. Different laser pulse durations, from nanoseconds to picoseconds, can be used to change surface morphology. Conversely, the characteristics that minimise the SEY, such as the moderately deep grooves and the redeposited nanoparticles, might have unfavourable consequences, including increased RF surface resistance. In this study, we describe the techniques used to measure the surface resistance of laser-treated copper samples using an enhanced dielectric resonator with 12 cm diameter sample sizes operating in the GHz range. The quantification basis lies in a non-contact measurement of the high-frequency losses, focusing on understanding the variation of surface resistance levels depending on the specifics of the treatment and possible post-treatment cleaning procedures.
Elettra 2.0: The Vacuum System Design for a New Generation Storage Ring
Authors: Novinec L. , Loda G. , Scrimali G. , Cudin I. , Rumiz L.
Published: January 2024

Next-generation synchrotron facilities currently under development and construction are promising and delivering great advances in terms of machine design and research physics. At the same time, they are pushing the limits of technological solutions for various subsystems: to achieve the desired ultra-low electron beam emittance required in the next generation machines, the magnetic lattice has to adopt a compact design with reduced magnet apertures and other constraints like high heat load from synchrotron radiation, dynamic pressure inside vacuum chambers and chamber wall impedance are presenting unique challenges for the vacuum and engineering teams. At Elettra-Sincrotrone Trieste (Italy), the Elettra 2.0 project aims to develop a new-generation storage ring. Taking into consideration the above-mentioned constraints, we decided to adopt a new design of a vacuum chamber, while utilizing novel pumping solutions to overcome hugely reduced conductance compared to the current machine. Large sputter ion pumps (SIP) will be in the majority replaced by distributed non-evaporable getter (NEG) coatings and small NEG cartridges and SIP pumps. For the synchrotron radiation handling, due to the tight space constraints imposed by the compact lattice, the photon absorption will be managed jointly with discrete and distributed solutions: photon absorbers have been carefully studied for combining compact form and high power density loads, while key sections of the new storage ring will be water-cooled. Throughout the whole development phase, we were using Monte-Carlo simulation codes like SynRad and MolFlow+ as effective tools supporting the design of new vacuum chambers and photon absorbers. The current state of development for the Elettra 2.0 vacuum system, the challenges we faced and the solutions we adopted are presented here.
Progress in Development and Measurement of an Asymmetric Magnet Pole Undulator
Authors: Mishra G. , Bindua Chilukamarri , Gehlot Mona , Khullar Roma
Published: January 2024

A new prototype undulator known as Asymmetric magnet pole with upper and lower structure having differ-ent period lengths will be designed and fabricated
Ultra-fast generator for impact ionization triggering
Authors: del Barrio Montañés A. A. , Senaj V. , Kramer T. , Dutheil Y. , Sack M.
Published: January 2024

In recent years, it has been discovered that thyristors triggered in impact ionization mode find their dI/dt capability boosted by up to three orders of magnitude. This innovative triggering requires applying an important overvoltage on the anode-cathode of the thyristor with a slew rate > 1 kV/ns. Compact pulse generators based on commercial off the shelf components (COTS) would allow the spread of this technology into numerous applications, including fast kicker generators for particle accelerators.

Our approach for such a compact pulse generator begins with a HV SiC MOS with an ultra-fast super-boosting gate driver. Super boosting in the gate of a 1.7 kV rated SiC MOS allows to reduce its rise time by a factor of ≈ 30 (datasheet tr = 20 ns vs. measured tr < 680 ps), resulting in an output voltage slew rate > 1 kV/ns and an amplitude > 1 kV.

Next, additional boosting is obtained by a Marx generator with D2PAK thyristors, reaching an output voltage slew rate > 16 kV/ns. Finally, creating sufficient current necessary for the triggering of a big thyristor presents a new challenge. In this paper, we present an upgraded board design with a higher current output capacity.
Additively manufactured tantalum cathode for FEBIAD type ion sources: production, geometric measurements, and high temperature test
Authors: Girotto A , Ballan M , Rebesan P , Dima R , Monetti A , Bodini I , Paderno D , Villa V , Pepato A , Manzolaro M
Published: January 2024

The Laser Powder Bed Fusion (LPBF) is an Additive Manufacturing (AM) technology suitable to produce almost free-form metallic components. At Legnaro National Laboratories (LNL) of the Italian National Institute for Nuclear Physics (INFN), the LPBF process was recently used to produce parts of the Forced Electron Beam Induced Arc Discharge (FEBIAD) ion source for the SPES Isotope Separation On-Line (ISOL) facility. In this work are presented the feasibility assessment and production steps of tantalum cathodes produced via AM; in addition, the results concerning both the dimensional-geometrical measurements and the preliminary high-temperature test are reported.
Design and Test of C-band Linac Prototypes for Electron FLASH Radiotherapy
Authors: Giuliano L. , Bosco F. , Carillo M. , Ficcadenti L. , Magi M. , Mostacci A. , Palumbo l L. , Migliorati M. , Faillace L. , Alesini D. , Faillace L. , Gallo A. , Iovine P. , Spataro B. , Felici G. , Di Francesco M.
Published: January 2024

Flash Therapy is a revolution in cancer cure since it spares healthy tissue from the damage of ionization radiations without decreasing its effectiveness in tumor control. To allow the implementation of the FLASH therapy concept into actual clinical use and treat deep tumors, Very High Electron Energy (VHEE) should be achieved in a range of 50-150 MeV. In the framework of the VHEE project carried out at Sapienza University, in collaboration with INFN, we investigate the main issues in designing a compact C band (5.712 GHz) electron linacs for FLASH Radiotherapy. In this paper, we describe the design strategy, the electromagnetic properties, and the first prototypes of the RF structures to be tested at Sapienza University.
Comparison of measurements and simulation results of dose for the flash radiation therapy beamline at PITZ
Authors: Amirkhanyan Z. , Aftab N. , Adhikari G. , Boonpornprasert P. , Georgiev G. , Grebinyk A. , Gross M. , Hoffmann A. , Krasilnikov M. , Kuhl T. , Li X. K. , Oppelt A. , Philipp S. , Riemer F. , Richard C. , Vashchenko G. , Stephan F. , Khachatryan V.
Published: January 2024

The high-brightness electron beam at the Photo Injector Test facility at DESY in Zeuthen (PITZ) is now also used for FLASHlab@PITZ: an R.&D platform for studying radiation biology and the FLASH effect in radiation therapy. The available parameter space of the electron beam with a momentum of 22 MeV/c allows bunch charges from 1 pC up to 5 nC, bunch durations of 0.160 ps and bunch train lengths up to 1 ms. The number of bunches in the single train can currently be varied between 1 and 1000 bunches, with an upgrade to 4500 foreseen in 2023. Radiation biology studies require accurate dose predic-tion, therefore Monte Carlo simulations based on the FLUKA code were performed. According to estimations, dose delivery of 0.002 Gy (low charge case 1 pC) and 10 Gy (high charge case 5 nC) is possible, if the beam is confined to a circular area with a radius of 5 mm with a lead collimator. For the Monte Carlo simulations, the experimental setup was accurately modelled, including the exit window, lead collimator, etc. Dose measurements were used to compare simulations with experiments. Dose profiles were experimentally measured with Gafchromic films and then compared with Monte Carlo simulations. The first experiments at FLASHlab@PITZ in 2023 have demonstrated flexible dose options for studying the FLASH effect and radiation biology studies.
Barycentric decomposition for quantum instruments
Authors: Pellonpää Juha-Pekka , Haapasalo Erkka , Uola Roope
Published: January 2024

We present a barycentric decomposition for quantum instruments whose output space is finite-dimensional and input space is separable. As a special case, we obtain a barycentric decomposition for channels between such spaces and for normalized positive-operator-valued measures in separable Hilbert spaces. This extends the known results by Ali and Chiribella et al on decompositions of quantum measurements, and formalizes the fact that every instrument between finite-dimensional Hilbert spaces can be represented using only finite-outcome instruments.
Three dimensional (bio)printing of blood vessels: from vascularized tissues to functional arteries
Authors: Makode Shubham , Maurya Satyajit , Niknam Seyed A , Mollocana-Lara Evelyn , Jaberi Kiana , Faramarzi Negar , Tamayol Ali , Mortazavi Mehdi
Published: January 2024

Tissue engineering has emerged as a strategy for producing functional tissues and organs to treat diseases and injuries. Many chronic conditions directly or indirectly affect normal blood vessel functioning, necessary for material exchange and transport through the body and within tissue-engineered constructs. The interest in vascular tissue engineering is due to two reasons: (1) functional grafts can be used to replace diseased blood vessels, and (2) engineering effective vasculature within other engineered tissues enables connection with the host’s circulatory system, supporting their survival. Among various practices, (bio)printing has emerged as a powerful tool to engineer biomimetic constructs. This has been made possible with precise control of cell deposition and matrix environment along with the advancements in biomaterials. (Bio)printing has been used for both engineering stand-alone vascular grafts as well as vasculature within engineered tissues for regenerative applications. In this review article, we discuss various conditions associated with blood vessels, the need for artificial blood vessels, the anatomy and physiology of different blood vessels, available 3D (bio)printing techniques to fabricate tissue-engineered vascular grafts and vasculature in scaffolds, and the comparison among the different techniques. We conclude our review with a brief discussion about future opportunities in the area of blood vessel tissue engineering.
Hydrodynamic shear stress’ impact on mammalian cell properties and its applications in 3D bioprinting
Authors: Zhang Yani , O’Mahony Aidan , He Yong , Barber Tracie
Published: January 2024

As an effective cell assembly method, three-dimensional bioprinting has been widely used in building organ models and tissue repair over the past decade. However, different shear stresses induced throughout the entire printing process can cause complex impacts on cell integrity, including reducing cell viability, provoking morphological changes and altering cellular functionalities. The potential effects that may occur and the conditions under which these effects manifest are not clearly understood. Here, we review systematically how different mammalian cells respond under shear stress. We enumerate available experimental apparatus, and we categorise properties that can be affected under disparate stress patterns. We also summarise cell damaging mathematical models as a predicting reference for the design of bioprinting systems. We concluded that it is essential to quantify specific cell resistance to shear stress for the optimisation of bioprinting systems. Besides, as substantial positive impacts, including inducing cell alignment and promoting cell motility, can be generated by shear stress, we suggest that we find the proper range of shear stress and actively utilise its positive influences in the development of future systems.
A microscale 3D organ on a chip for recapitulating reciprocal neuroendocrine crosstalk between the hypothalamus and the pituitary gland
Authors: Park Se-Ra , Kook Myung Geun , Kim Soo-Rim , Lee Jin Woo , Yu Young Soo , Park Chan Hum , Lim Soyi , Oh Byung-Chul , Jung YunJae , Hong In-Sun
Published: January 2024

Conventional 2D or even recently developed 3D in vitro culture models for hypothalamus and pituitary gland cannot successfully recapitulate reciprocal neuroendocrine communications between these two pivotal neuroendocrine tissues known to play an essential role in controlling the body’s endocrine system, survival, and reproduction. In addition, most current vitro culture models for neuroendocrine tissues fail to properly reflect their complex multicellular structure. In this context, we developed a novel microscale chip platform, termed the ‘hypothalamic–pituitary (HP) axis-on-a-chip,’ which integrates various cellular components of the hypothalamus and pituitary gland with biomaterials such as collagen and hyaluronic acid. We used non-toxic blood coagulation factors (fibrinogen and thrombin) as natural cross-linking agents to increase the mechanical strength of biomaterials without showing residual toxicity to overcome drawbacks of conventional chemical cross-linking agents. Furthermore, we identified and verified SERPINB2 as a reliable neuroendocrine toxic marker, with its expression significantly increased in both hypothalamus and pituitary gland cells following exposure to various types of toxins. Next, we introduced SERPINB2-fluorescence reporter system into loaded hypothalamic cells and pituitary gland cells within each chamber of the HP axis on a chip, respectively. By incorporating this SERPINB2 detection system into the loaded hypothalamic and pituitary gland cells within our chip platform, Our HP axis-on-chip platform can better mimic reciprocal neuroendocrine crosstalk between the hypothalamus and the pituitary gland in the brain microenvironments with improved efficiency in evaluating neuroendocrine toxicities of certain drug candidates.
Evaluation of zirconia surfaces and shear bond strength after acid–etching with ultrasonic vibration
Authors: Zhang Xiaozhen , Nie Hepeng , Lv Jiaxin , Yuan Shanshan , Wang Juan , Cai Kunzhan , Wu Jin , Zhang Qingqing , Tang Chunbo
Published: January 2024

To evaluate the effect of surface reaction process after hydrofluoric (HF) acid etching using ultrasound and the shear bond strength (SBS) of resin cement to zirconia polycrystal (Y-TZP) ceramic. Y-TZP ceramic sheets were divided into rinsing group (Group P), ultrasonic cleaning group (Group C), and ultrasonic reaction + rinsing group (Group CP), and all the groups were treated for 5, 10, 20, 30, 40, 50, and 60 min, respectively. The surface morphology, elements distribution, roughness, and wettability of the ceramic sheets in each group were observed. The SBS of ceramic-resin bonding specimens was tested after immersion and after cooling-heating cycles, respectively. Octahedral and spiculate products were observed on the surface of Y-TZP that was etched with HF acid in Group P. The amount of these products increased over time. In contrast, only a few octahedral products remained on the surface of Y-TZP in Groups C and CP. Within the same reaction time, the surface reaction of the CP group was stronger than that of the other two groups, accompanied by a more uniform morphology. The shear force in Group C was the lowest, and the shear force reduction in Group CP was the least after cooling-heating cycling, with statistically significant differences (P< 0.05). After the reaction time exceeded 30 min, the shear force in each group decreased instead of increasing. Octahedral and spiculate acid etching products on the surface of HF acid-etched Y-TZP can enhance the bonding force of zirconia. Ultrasonic cleaning would drive the exfoliation of acid etching products from the sample surface, leading to the decrease of the bonding force. The acid etching with ultrasonic vibration can accelerate the HF acid etching process of Y-TZP ceramics, which is conducive to improving the bond strength to resin and durability.
Do changing circulation types raise the frequency of summertime thunderstorms and large hail in Europe?
Authors: Ghasemifard Homa , Groenemeijer Pieter , Battaglioli Francesco , Púčik Tomáš
Published: January 2024

We study the role of changes in circulation type frequency on the evolution of summertime thunderstorm and large hail frequency across Europe since 1950 until 2020 to find out if they are responsible for the changes that an additive regression convective hazard models model (AR-CHaMo) predicts to have happened. To define circulation types, the 500 hPa geopotential height anomaly field on each day was clustered into 14 distinct patterns using principal component analysis and k-means clustering. We show that lightning and hail occurrence, both observed and modeled by AR-CHaMo, strongly depend on the circulation type, with a higher frequency observed in poleward flow downstream of a trough and on the lee side of mountains. AR-CHaMo predicts strong increases in hail frequency across central parts of Europe to have occurred in the 1950–2020 period. During this period, changes in circulation type frequency are small and only significant for 2 of the 14 clusters. The trends in both lightning and hail frequency to be expected if they were solely determined by circulation patterns, are small, with typical values of 1%–3% per decade relative to the mean, whereas the trends expected by AR-CHaMo are on the order of 4%–10% in most areas. Across many regions, the sign of the changes does not agree in sign, in particular across European Russia where circulation types have become more favorable for lightning and hail, but a decreasing probability was modeled by AR-CHaMo. We conclude that changing circulation types are, in general, not responsible for changes in thunderstorm and hail frequency, which included the strong increase of conditions favorable for large hail in central Europe.
Products of hyperelliptic Jacobians with maximal Galois image
Authors: Garnek Jędrzej
Published: January 2024

In this note we study the associated adelic representation of a product of hyperelliptic Jacobians. We give a simple criterion that ensures that this representation has maximal Galois image in a certain sense. As an application, we provide a method of constructing products of Jacobians with division fields as disjoint as they can be.
Deformations of commutative Artinian algebras
Authors: Aleksandrov A.
Published: January 2024

The paper is devoted to the study of deformations of Artinian algebras and zero-dimensional germs of varieties. In particular, an approach is developed to solving the open problem about the nonexistence of rigid Artinian algebras; it is based essentially on the use of the canonical duality in the cotangent complex. Thus, it is shown that there are no rigid Gorenstein Artinian algebras and rigid almost complete intersections. The proof of the latter statement is based on the properties of the torsion functors. More precisely, the tensor product of the conormal and canonical modules of the corresponding Artinian algebra is calculated. In this case, the homology and cohomology groups of higher degrees are also found. Among other things, some estimates are obtained for the dimension of the spaces of the first lower and upper cotangent functors of Artinian algebras, and the relationship between them is described. In conclusion, several examples of nonsmoothable Artinian noncomplete intersections are examined, and some unusual properties of such algebras are discussed.
Dubrovin method and the Toda chain
Authors: Matveev V. , Smirnov A.
Published: January 2024

A hierarchy of Lax pairs with

2
×
2

2\times 2

matrix coefficients is presented. The compatibility conditions for these pairs include the Toda chain equation, and other differential-difference integrable systems. Various kinds of finite gap solutions for such systems are constructed. Examples of simplest one- and two-phase solutions are given, together with the corresponding spectral curves.
COVID-19 and Mental Health: Natural Experiments of the Costs of Lockdowns
Authors: Quintana-Domeque Climent , Zeng Jingya
Published: January 2024

The global impact of the COVID-19 pandemic has been profound, leaving a significant imprint on physical health, the economy, and mental well-being. Researchers have undertaken empirical investigations across different countries, with a primary focus on understanding the association between lockdown measures—an essential public health intervention—and mental health. These studies aim to discern the causal effect of lockdowns on mental well-being. Three notable studies have adopted natural experiments to explore the causal effect of lockdowns on mental health in diverse countries. Despite variations in their research methodologies, these studies collectively support the conclusion that lockdowns have had detrimental consequences on mental health. Furthermore, they reveal that the intensity of these negative effects varies among distinct population groups. Certain segments of the population, such as women, have borne a more profound burden of the mental health costs associated with lockdown measures. In light of these findings, it becomes imperative to consider the implications for mental health when implementing public health interventions, especially during crises like the COVID-19 pandemic. While rigorous measures like lockdowns are essential for safeguarding public health, striking a balance with robust mental health support policies becomes crucial to mitigating the adverse impacts on mental well-being.
Rahman, Fazlur
Authors: Moosa Ebrahim
Published: January 2024

Fazlur Rahman was a preeminent 20th-century Muslim scholar who combined modernism with tradition. He saw his role as that of shaping the study of Islam in the modern Western academy with the empathy of a believer and a critical scholarly acumen. Grounded in philosophy, theology, history, and moral thought, he advocated for a reinterpretation of the early sources of Islamic learning—emphasizing, for example, the more organic Sunnah instead of the atomistic prophetic reports in the form of ḥadīth. Critical of some aspects of the transmitted discursive tradition, he nevertheless viewed tradition as indispensable to the renewal of Islamic thought. He placed the Qurʾān and his specific hermeneutic of the historicized thematics of the revelation at the center of his renewal and reform project. While he took history seriously, in the end a scripture-centered hermeneutic became his preferred discursive framework.
Islam in Latin America
Authors: Montenegro Silvia
Published: January 2024

Muslim presence in Latin America is associated with migration processes, with the transnationalization of interpretations of Islam spreading to the region, and with varying stages of institutionalization and growth of the communities in each of the countries involved. There are two previous records of a modest Muslim inflow: Moriscos (i.e., crypto-Muslims who arrived in the Americas after the conquest) and the expressions of Islam brought by enslaved Africans transported to the continent to serve as labor from the 17th century onward. In the Southern Cone, it was Arab immigrants who reinvigorated the presence of Islam; in the Caribbean and the Guianas, indentured laborers from India and Indonesia. In some countries, there have been communities institutionally organized around centers and associations since the early 20th century; in others, the institutionalization process started in the late 1980s. In predominantly Catholic Latin America, Islam has always taken on the form of a religious minority, composed of immigrants of various backgrounds and later also of Latin American converts. Latin American countries have been recipients of expansion projects by certain branches of Muslim tradition, including Shi’ism, promoted by Iran after the 1979 revolution; Saudi Wahhabism; the transnationalization of Sufi orders coming from Asia, such as Naqshbandiyya-Haqqaniyya and Halveti-Jerrahiyya. Worldwide Islam-spreading movements, such as Tablighi Jamaat, Ahmadiyya, and the Murabitun World Movement, also became global, reaching some Latin American countries.
Long-term impact of the COVID-19 pandemic on the quality of life of people with dementia and their family carers
Authors: Read Sanna , Hicks Ben , Budden Emily , Douglass Jacob , Grahamslaw Amanda , Herrero Elena , Joseph Gregory , Kirkup Christine , Pusey Martha , Russell Alice , Sondh Harsharon , Sondh Sharon , Storey Bryony , Towson Georgia , Baxter Kate , Birks Yvonne , Brayne Carol , Colclough Carmen , Dangoor Margaret , Dixon Josie , Donaghy Paul , Gridley Kate , Harris Peter R , Hu Bo , King Derek , Knapp Martin , Miles Eleanor , Mueller Christoph , Perach Rotem , Robinson Louise , Rusted Jennifer , Thomas Alan J , Wittenberg Raphael , Banerjee Sube
Published: January 2024

Introduction

Few studies have longitudinally mapped quality of life (QoL) trajectories of newly diagnosed people with dementia and their carers, particularly during coronavirus disease-2019 (COVID-19).

Methods

In a UK cohort study, 261 newly diagnosed people with dementia and 206 family carers were assessed prior to the pandemic (July 2019–March 2020), followed up after the first lockdown (July–October 2020) and then again a year and 2 years later. Latent growth curve modelling examined the level and change of QoL over the four time-points using dementia-specific QoL measures (DEMQOL and C-DEMQOL).

Results

Despite variations in individual change scores, our results suggest that generally people with dementia maintained their QoL during the pandemic and experienced some increase towards the end of the period. This contrasted with carers who reported a general deterioration in their QoL over the same period. ‘Confidence in future’ and ‘Feeling supported’ were the only carer QoL subscales to show some recovery post-pandemic.

Discussion

It is positive that even during a period of global disruption, decline in QoL is not inevitable following the onset of dementia. However, it is of concern that carer QoL declined during this same period even after COVID-19 restrictions had been lifted. Carers play an invaluable role in the lives of people with dementia and wider society, and our findings suggest that, post-pandemic, they may require greater support to maintain their QoL.