Next generation ion therapy magnets both for gantry and for accelerator (synchrotron) are under investigation in a recently launched European collaboration that, in the frame of the European H2020 ...HITRI plus and I.FAST programmes, has obtained some funding for work packages on superconducting magnets. Design and technology of superconducting magnets will be developed for ion therapy synchrotron and -especially- gantry, taking as reference beams of 430 MeV/nucleon ions (C-ions) with 10 10 ions/pulse. The magnets are about 60-90 mm diameter, 4 to 5 T peak field with a field change of about 0.3 T/s and good field quality. The paper will illustrate the organization of the collaboration and the technical program. Various superconductor options (LTS, MgB 2 or HTS) and different magnet shapes, like classical CosTheta or innovative Canted CosTheta (CCT), with curved multifunction (dipole and quadrupole), are under evaluation, CCT being the baseline. These studies should provide design inputs for a new superconducting gantry design for existing facilities and, on a longer time scale, for a brand-new hadron therapy centre to be placed in the South East Europe (SEEIIST project).
A novel scintillator detector, the SuperFGD, has been selected as the main neutrino target for an upgrade of the T2K experiment ND280 near detector. The detector design will allow nearly 4π coverage ...for neutrino interactions at the near detector and will provide lower energy thresholds, significantly reducing systematic errors for the experiment. The SuperFGD is made of optically-isolated scintillator cubes of size 10×10×10 mm3, providing the required spatial and energy resolution to reduce systematic uncertainties for future T2K runs. The SuperFGD for T2K will have close to two million cubes in a 1920×560×1840 mm3 volume. A prototype made of 24×8×48 cubes was tested at a charged particle beamline at the CERN PS facility. The SuperFGD Prototype was instrumented with readout electronics similar to the future implementation for T2K . Results on electronics and detector response are reported in this paper, along with a discussion of the 3D reconstruction capabilities of this type of detector. Several physics analyses with the prototype data are also discussed, including a study of stopping protons.
The CTF3 Two-beam Test Stand Ruber, R.; Ziemann, V.; Ekelöf, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2013, Letnik:
729
Journal Article
Recenzirano
The Two-beam Test Stand (TBTS) has been constructed and operated at the CLIC test facility CTF3 at CERN. The TBTS comprises two parallel and independent electron beam lines and has been designed to ...demonstrate the feasibility of a two-beam high gradient acceleration concept as proposed for the Compact Linear Collider (CLIC). In the CLIC scheme, the RF power is extracted from a high current drive beam using RF power extraction structures while the main beam is accelerated using this RF power which is fed into high gradient high frequency normal conducting accelerating structures.
The Two-beam Test Stand is a unique facility to demonstrate the feasibility of the CLIC two-beam high gradient acceleration concept and to test the individual CLIC components and complete two-beam CLIC modules. The TBTS is particularly well suited to investigate the effects on the beam of RF breakdown in the high gradient accelerating structures. We report on the design, construction and commissioning of the Two-beam Test Stand.
Spectrometers for RF breakdown studies for CLIC Jacewicz, M.; Ziemann, V.; Ekelöf, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2016, Letnik:
828
Journal Article
Recenzirano
Odprti dostop
An e+e− collider of several TeV energy will be needed for the precision studies of any new physics discovered at the LHC collider at CERN. One promising candidate is CLIC, a linear collider which is ...based on a two-beam acceleration scheme that efficiently solves the problem of power distribution to the acceleration structures. The phenomenon that currently prevents achieving high accelerating gradients in high energy accelerators such as the CLIC is the electrical breakdown at very high electrical field. The ongoing experimental work within the CLIC collaboration is trying to benchmark the theoretical models focusing on the physics of vacuum breakdown which is responsible for the discharges. In order to validate the feasibility of accelerating structures and observe the characteristics of the vacuum discharges and their eroding effects on the structure two dedicated spectrometers are now commissioned at the high-power test-stands at CERN.
First, the so called Flashbox has opened up a possibility for non-invasive studies of the emitted breakdown currents during two-beam acceleration experiments. It gives a unique possibility to measure the energy of electrons and ions in combination with the arrival time spectra and to put that in context with accelerated beam, which is not possible at any of the other existing test-stands.
The second instrument, a spectrometer for detection of the dark and breakdown currents, is operated at one of the 12GHz stand-alone test-stands at CERN. Built for high repetition rate operation it can measure the spatial and energy distributions of the electrons emitted from the acceleration structure during a single RF pulse. Two new analysis tools: discharge impedance tracking and tomographic image reconstruction, applied to the data from the spectrometer make possible for the first time to obtain the location of the breakdown inside the structure both in the transversal and longitudinal direction thus giving a more complete picture of the vacuum breakdown phenomenon.
In this paper, we present the physics performance of the ESSnuSB experiment in the standard three flavor scenario using the updated neutrino flux calculated specifically for the ESSnuSB configuration ...and updated migration matrices for the far detector. Taking conservative systematic uncertainties corresponding to a normalization error of Formula omitted for signal and Formula omitted for background, we find that there is Formula omitted Formula omitted CP violation discovery sensitivity for the baseline option of 540 km (360 km) at Formula omitted. The corresponding fraction of Formula omitted for which CP violation can be discovered at more than Formula omitted is Formula omitted. Regarding CP precision measurements, the Formula omitted error associated with Formula omitted is around Formula omitted and with Formula omitted is around Formula omitted Formula omitted for the baseline option of 540 km (360 km). For hierarchy sensitivity, one can have Formula omitted sensitivity for 540 km baseline except Formula omitted and Formula omitted sensitivity for 360 km baseline for all values of Formula omitted. The octant of Formula omitted can be determined at Formula omitted for the values of: Formula omitted ( Formula omitted and Formula omitted) for baseline of 540 km (360 km). Regarding measurement precision of the atmospheric mixing parameters, the allowed values at Formula omitted are: Formula omitted ( Formula omitted) and Formula omitted eV Formula omitted eV Formula omitted ( Formula omitted eV Formula omitted eV Formula omitted) for the baseline of 540 km (360 km).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The European Spallation Source (ESS), currently under construction in Lund, Sweden, is a research center that will provide, by 2023, the world’s most powerful neutron source. The average power of the ...proton linac will be 5 MW. Pulsing this linac at higher frequency will make it possible to raise the average total beam power to 10 MW to produce, in parallel with the spallation neutron production, a very intense neutrino Super Beam of about 0.4 GeV mean neutrino energy. This will allow searching for leptonic CP violation at the second oscillation maximum where the sensitivity is about 3 times higher than at the first. The ESS neutrino Super Beam, ESSnuSB operated with a 2.0 GeV linac proton beam, together with a large underground Water Cherenkov detector located at 540 km from Lund, will make it possible to discover leptonic CP violation at 5σ significance level in 56% (65% for an upgrade to 2.5 GeV beam energy) of the leptonic CP-violating phase range after 10 years of data taking, assuming a 5% systematic error in the neutrino flux and 10% in the neutrino cross section. The paper presents the outstanding physics reach possible for CP violation with ESSnuSB obtainable under these assumptions for the systematic errors. It also describes the upgrade of the ESS accelerator complex required for ESSnuSB.
Abstract
A compression of the ESS proton pulse from the present 2.86 milliseconds to a medium pulse length of a few tens of microseconds which is better matched to the moderator time-constant of ...thermal neutrons would considerably boost the performance for many instruments at ESS. Generating such a proton pulse with preserved instantaneous beam power requires a storage ring to be added to the ESS accelerator. Such a ring has been studied within the ESSnuSB neutrino super-beam study. The proton pulse length extracted in single turn extraction from this ring would be approximately 1 microsecond long which could be destructive for the present ESS target and is very short compared to the moderator time constant. The more desirable medium length pulse could possibly be generated by multi-turn extraction and a new concept using a cyclotron like extraction scheme in a synchrotron or a FFA. Another way to generate the longer pulses is to extract a bunch train using fast strip line kickers but this would require a larger storage ring. Using a “bunch train” has been successfully applied at the CERN ISOLDE facility to avoid destruction of sensitive liquid metal targets used for Nuclear Physics experiments. Other challenges are linked to the injection into the storage rings and the understanding of the target, moderator and neutron extraction systems with short and medium pulse length.
Abstract
The FREIA Laboratory at Uppsala University focuses on superconducting technology and accelerator development. It actively supports the development of the European Spallation Source, CERN, ...and MAX IV, among others. FREIA has developed test facilities for superconducting accelerator technology such as a double-cavity horizontal test cryostat, a vertical cryostat with a novel magnetic field compensation scheme, and a test stand for short cryomodules. Accelerating cavities have been tested in the horizontal cryostat, crab-cavities cavities in the vertical cryostat, and cryomodules for ESS on the cryomodule test stand. High power radio-frequency amplifier prototypes based on vacuum tube technology were developed for driving spoke cavities. Solid-state amplifiers and power combiners are under development for future projects. We present the status of the FREIA Laboratory complemented with results of recent projects and future prospects.
A comprehensive simulation study of the feasibility of an earlier proposed tau-neutrino appearance experiment based on a RICH with liquid radiator (C6F14) has been performed. Tau leptons, that are ...created in charged current interactions of incident tau neutrinos with the same momentum spectrum as that of the planned Gran Sasso beam (average 17GeV/c), have an average track length of about 0.5mm. Cherenkov photons emitted in the liquid radiator from the short track of the tau lepton provide a characteristic pattern for tau-neutrino appearance. In the present report it is shown, on the basis of simulations performed with the GEANT4 code, that Cherenkov radiation from delta electrons, originating from the interaction of the long-lived tau decay products with the Cherenkov radiator, constitutes a severe background that renders the detection of the millimeter-short tau track unfeasible. Increasing the incident neutrino beam momentum results in longer tau tracks and therefore more signal photons, but this does not solve the background problem since the kink angle between the tau track and the secondary decay particle decreases with increasing neutrino momentum, leading to an increased overlap between the Cherenkov rings of these two particles.
The aim of the NorduGrid project is to build and operate a production grid infrastructure in Scandinavia and Finland. By developing innovative middleware solutions, it enables a 24/7 production-level ...test bed. Through a common access layer, NorduGrid connects a dynamic set of computing resources, ranging from small test clusters at academic institutions to large farms at several supercomputer centers. This article reviews the architecture and describes the grid services implemented via the NorduGrid middleware. The authors describe a case study of a demanding high-energy physics application.
PDF
