Conveners
Poster session
- Alessandro Grelli (Utrecht University (NL))
The Future Circular Collider (FCC-hh) will have a beam screen with T between 20 and 60 K. Electron cloud mitigation will be critical for the FCC-hh and it has been specified that the wall material needs to have a Secondary Electron Yield (SEY) < 1. Since the LASE surfaces with SEY<1 are the baseline electron cloud mitigation technique, it is critically important to study the behaviour of the...
The sizes of the beta functions in the final focus triplet of a synchrotron collider have a great impact on the chromaticity and dynamic aperture of the machine. These beta functions are proportional to the square of the length of the final drift so it is desirable to keep it as short as possible whilst leaving enough room for the experiment. In the latest design of the FCC-hh this drift was...
One of the critical parameters of the high Jc internal tin Nb3Sn strands designated for the high field magnets of the FCC project is essentially high RRR value exceeding 150. In this work Oxygen free high-purity copper with RRR>400 was used for production of internal tin Nb3Sn wires of 0,7 and 1 mm in dia with 37 sub-elements in distributed diffusion Nb-barriers. Final reactions from 25 to...
One of the biggest challenges in the design of the FCC-hh is the collimation system. From LHC experience it is known that a collimation system optimized for proton cleaning has a significantly reduced efficiency for heavy ions. The study presented in this contribution evaluates the betatron-collimation efficiency for the heavy-ion operation with lead nuclei at a beam energy of 50 Z TeV in the...
An analytical electron positron circular collider optimized design method has been developed with carb-waist collision and CEPC parameters for Higgs, W and Z have been given by this method. For the lattice of CEPC collider ring, the combined magnet (dipole+sextupole)scheme has been developed to reduced the power consumption of the stand-alone sextupoles. The power consumption of the original...
This contribution presents our collider availability model used in FCC study. The model represents failure logics, operations and calculates the integrated luminosity productions, which is one of the key performance indicator for colliders. The operation phases are essential part of the collider model, as several steps are required to prepare the collider for collisions. This means that the...
We probe the effects of dimension-eight operators giving rise to anomalous neutral triple gauge boson interactions of Z𝛾𝛾 and Z𝛾Z vertices in l-l+𝛾 production (pp→ l-l+𝛾) at 100 TeV centre of mass energy of future circular hadron collider, namely FCC-hh. The analysis is performed on transverse momentum of photon and angular distribution of charged lepton in the final state including a...
Superconducting niobium-tin (Nb3Sn) wires have become a key technology for the development of next generation accelerator magnets. These conductors can be described by their high critical current density but also by their remarkable strain-dependent behavior. In presence of mechanical loads, the superconducting lattice is distorted resulting usually in a reversible decrease of the critical...
In FCC-hh, one of the most challenging issue will be to limit all possible instabilities that could occur. Expected instabilities are mainly related to the large number of photons and photoelectrons present in the vacuum beam-pipe. Photons and photoelectrons will induce gas desorption and single beam instabilities, whereas at LHC instabilities are dominated by e-cloud formation. It is,...
This work presents a study of Higgs boson production in jets and missing energy final states at the FCC-ee collider. In particular, we explore how different detector parameters and the beam strahlung affect the sensitivity of Higgs boson coupling measurements.
In this paper we aim to reveal methods that can decrease the time spent on the mechanical elements development increasing the efficiency of the process. The challenge in this scheme is the optimization of a large number and variety of components in the ITER diagnostic system. During our work we compared the engineering requirements with the specific requirements of a fusion power plant.
Our...
The stress-strain behaviour of the Nb3Sn conductor blocks of the superconducting coils for the Future Circular Collider (FCC) magnets need to be known in order to predict the stress state distribution in the coils during magnet assembly and operation. The stress-strain behaviour of reacted and impregnated 11 T Rutherford cable stacks has been determined using a dedicated set-up with an...
FCC-ee special features for the high energy running, description of top precision measurements at threshold and above and implications for new physics.
In the framework of the EuCARD-2 WP-10 program, CERN has produced two sets of High Temperature Superconductor (HTS) insert-magnets wound with ReBCO-Roebel cable, named FeaTHeR-M2 and FeaTHeR-M0. FeaTHeR-M2 is an aligned block magnet designed to generate 5 T in a 40 mm aperture, whereas FeaTHeR-M0 are sub-scale planar racetrack coils designed to test fabrication techniques and gain experience...
The beam-beam interaction is one of the most severe limitations on the performance of circular colliders, as it is an unavoidable strong nonlinear effect. As one aspires for greater luminosity in future colliders, one will simultaneously achieve stronger beam-beam interactions. We study the limitations caused by strong incoherent head-on beam-beam interactions, using a new GPU-based code...
The baseline design of the FCC-hh beam screen is based on an octagonal shaped stainless steel tube coated in its interior with copper. The surface impedance of the beam screen has a strong impact on the beam stability. In the foreseen operating temperature range between 40 K and 60 K the intended coating might not guarantee an impedance sufficiently low for a stable beam. This motivates the...
Dual-Readout calorimetry is a relatively new calorimetric technique able to overcome the non-compensation problem by means of two independent scintillation and Cherenkov light signal detections. Scintillating photons provide a signal proportional to the whole energy deposition in the calorimeter while Cherenkov photons emitted in clear fibers provide a signal almost exclusively related to the...
CEPC is a 100 km circular electron-positron collider operating at 90-240 GeV center-of-mass energy of Z-pole, WW pair production threshold, and Higgs resonance. CEPC and its successor SPPC, a 100 TeV center-of-mass super proton-proton collider, will ensure the elementary particle physics a vibrant field for decades to come. To reduce the overall cost, partial double ring scheme was proposed as...
At high proton-beam energies, beam-induced synchrotron radiation is an important source of
heating, of beam-related vacuum pressure increase, and of primary photoelectrons, which can give
rise to an electron cloud. We present the synchrotron radiation map computed by Synrad3D for the latest shape of the FCC-hh vacuum chamber with a sawtooth surface instead of a wedge.
With the discovery of the Higgs boson at around 125GeV, a circular Higgs factory design with high luminosity (L ~ 10^34 cm^-2 s^-1) is becoming more popular in the accelerator world. The CEPC project in China is one of them. Machine Detector Interface (MDI) is the key research area in electron-positron colliders, especially in CEPC, it is one of the criteria to measure the accelerator and...
In the framework of the FCC study, the Nb3Sn technology plays a crucial role for high-field superconducting magnets. The new generation Nb3Sn cable greatly contributes to bring the magnetic field produced by the superconducting dipole magnets to the 16 T level; nevertheless, its mechanical properties are unknown making it difficult to predict the mechanical behaviour of the magnet structure....
A part of the FCC-hh design study explores different superconducting materials, which could be suitable to function as a coating on the beam screen, held at 50 K. Such a superconducting coating should be able to carry the beam image currents and lower the beam impedance in order to guarantee a high beam stability margin. Our study focuses on the still technologically unexploited thallium-based...
We present results of microstructural examinations of grain size distribution, grain geometry, compositional gradients and local texture performed on Nb3Sn wires of various manufacturing techniques. Measurements were conducted using high-resolution TEM (transmission electron microscopy), EDX (energy-dispersive X-ray spectroscopy) and TKD (transmission Kikuchi diffraction). Findings include...
Minimising the thickness of TiZrV non-evaporable getter (NEG) coatings is mandatory for increasing single-bunch instability thresholds in the proposed FCC-ee high luminosity lepton collider. After thermal activation the NEG surface is depleted of its O content and the total electron yield (TEY) decreases to values close to 1.1. The effect of reducing the thickness of NEG coatings on activation...
The current cryogenic design for the FCC-hh consist of a helium cycle with pre-cooling by the Nelium cycle. Both have their own set of compressors and heat exchangers. The potential of combination of these two distinct cycles with a reduced number of components is investigated. Using efficient turbo compressors requires a mixed refrigerant with a heavier ballast gas to achieve reasonable...
The volume of data produced at the Large Hadron Collider (LHC) is immense and represent a considerable processing challenge. Moreover the LHC and future hadronic colliders are the most demanding environments, with respect to ultra-low latencies, ultra-high data rate, reliable indoor coverage and harsh radiation environment, in the world.
Any technology meeting the above conditions will have to...
Non-evaporable getter coating of vacuum chamber of particle accelerators was invented approximately 20 year ago by C. Benvenuti at CERN. This technology have already demonstrated its benefits an many machines: ESRF, Elettra, Diamond, Soleil, LHC, MAX-IV, etc. The NEG coatings are very effective vacuum solution, the UHV/XHV conditions could be reached in fully coated vacuum chamber of particle...
The CiS Forschungsinstitut fuer Mikrosensorik is engaged in developments of radiation detector technologies on several different fields. Current projects are dealing with large area thinned sensors, active edge sensors, 3D sensors, sensor-chip packaging technologies and defect engineering.
For large area sensors, the need for smaller thicknesses can be approached by etching cavities to the...
The vacuum chamber surface characteristics such as the photon and secondary electron yields (PEY and SEY) are critical for formation of an electron cloud, this is a serious problem that effects proton and positron accelerators. A few years ago it was discovered by us that Laser Ablation surface engineering (LASE) could provide surfaces with SEY<1. These LASE surfaces are the baseline design...
Likewise LHC, FCC tunnel should be carefully supervised to ensure safety of personnel. Nevertheless, in case of an accident, in order to increase success of the mission and reduce risks for rescue team, it will be crucial for firefighters to collect as much information as possible about the location of victims inside tunnel before entering the unsafe zone. Due to the large size of FCC, rapid...
The vacuum chamber of the FCC-hh will have to cope with unprecedented levels of synchrotron radiation power, dealing simultaneously with tighter impedance and magnet aperture requirements. Given that the high radiation power and photon flux will release larger amounts of gas into the system, new solutions for designing the beam-screen geometry and estimating the effective pumping speed and...
High field accelerators magnets will require coil grading, and thus low resistance joints (splices), in order to increase the magnetic field and decrease magnet cost. These joints must have low resistance (<1 nΩ) and reasonably good mechanical strength. Three techniques have been initially considered by the Applied Superconductivity group of the Swiss Plasma Center for the preparation of...
We analysed anomalous top FCNC couplings via the production of single top quark in association with a photon at 100 TeV centre of mass energy. In our analysis, we consider the invariant mass distributions of reconstructing top quark mass; one lepton and missing energy transfer reconstructing W, and one b-tagged jet for lvb𝛾 final state, and one b-tagged jet and two other jets reconstructing W...
In this study we consider the results of development and production low temperature superconductors on base of Nb3Sn by the “internal tin” method with critical current density more than 2450 A/mm2. The obtained superconductors of 1.0 to 0.7 mm in diameter of different layouts have been subjected to reaction by various regimes for the formation of the superconducting compound, and then their...
"In the collisions of proposed future circular colliders, like FCCee and CEPC, the beamstrahlung...
An innovative high-field superconducting dipole magnet of Canted-Cosine-Theta (CCT) type has been proposed for Future Circular Collider (FCC) design. The unique mechanical structure intercepts the accumulated forces lowering the stress on the windings. Nevertheless, the former itself also becomes a barrier for heat to quickly propagate in case of a quench. To succeed in the CCT-type magnet...
Developing a surface with low Secondary Electron Yield (SEY) is one of the principal methods of mitigating the beam-induced electron multipacting and electron cloud in high-energy charged particle accelerators. Since the wall material, surface chemistry, topography and electron energy are the parameters that influence the SEY, common mitigation mechanisms are based on engineering the above...
The baseline design of the FCC-hh beam screen is based on an octagonal shaped stainless-steel tube coated in its interior with copper. The surface impedance of the beam screen has a strong impact on the beam stability. In the foreseen operating temperature range from 40 K to 60 K the intended coating might not guarantee an impedance sufficiently low for a stable beam. This motivates the...
"Right-handed or, equivalently, sterile neutrinos are among the most attractive extensions of the SM to generate the light neutrino masses observed in neutrino oscillation experiments.
When the right-handed neutrinos are subject to a ""lepton number""-like symmetry they can have masses around the electroweak scale and potentially large Yukawa couplings, which makes them testable at the...
After the discovery of Higgs boson in LHC of CERN, Chinese scientists immediately proposed a plan to build next generation colliders -- CEPC&SPPC. SPPC (Super Proton Proton Collider) is the second phase of this project to explore new physics beyond the standard model. The key design goal for SPPC is to reach 75 TeV in center of mass energy with a circumference of 100 km. As an important part...
In the Highest Energy Proton Circular Collider ever designed, FCC-hh, a large production of Synchrotron Radiation (SR) is expected. This SR causes heat load on the accelerator walls, photon stimulated desorption, production of secondary electrons, beam instability, etc. Thus, it is very important to have an experimental characterization of optical properties of technical surfaces, in...
One of the many important parameters to be studied and fixed in the design of the FCC-hh is the operational temperature (T) at which the foreseen beam screen should operate. Such choice will necessarily be a compromise between the desire to reduce cooling costs (keeping it at as close as possible to room T) and to have a minimal wall resistivity (keeping it at as low as possible Ts). The...
Nb3Sn wire is the proposed type II superconductor to be used as the superconducting dipole magnet in Future Circular Collider (FCC) for its superior superconducting properties at high magnetic field (16T). Heat treatment and phase formation of Nb3Sn internal tin superconductors are quite complicated due to the need to convert low melting temperature tin-rich phases to high temperature...
The μ-RWELL has been conceived as a compact, simple and robust Micro-Pattern Gaseous Detector for large area HEP applications in a harsh environment. The detector amplification stage is realized with a polyimide foil micro-patterned with a blind-hole matrix embedded through a thin DLC resistive layer in the readout PCB. The introduction of this layer, mitigating the transition from streamer to...
The latest expected sensitivities for the search of flavor changing neutral current processes in top events at the FCC-ee collider run at 365 GeV will be presented in this poster.
The Canted-Cosine-Theta (CCT) PSI magnet program aims at demonstrating that the CCT technology has the potential for the development of 16 T dipole magnets, required for the “near” future of circular colliders. The first step in this direction is the implementation of a Nb3Sn 1-m-long, 2-layer CCT single-aperture dipole model, referred to as Canted Dipole One (CD1) which is designed to achieve...
Due to its advantages such as evenly distributed pumping speed, low thermal outgassing and low photon and electron stimulated desorption yields, the non-evaporable getter (NEG) coating has been used in particle accelerators for years. Even though quaternary Ti-Zr-Hf-V coating deposited from an allow wire has been found to have the lowest desorption yields, highest sticking probability and...
