Searcharxiv⌕ Search

SEARCH · Searcharxiv

Results for “physics.acc-ph”

Search indexed arXiv papers on artificial intelligence, large language models, computer vision and robotics. Read source abstracts and follow links to arXiv.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11Linked to original sources
arXiv2013

THz-radiation production using dispersively-selected flat electron bunches

We propose an alternative scheme for a tunable THz radiation source generated by relativistic electron bunches. This technique relies on the combination of dispersive selection and flat electron bunch. The dispersive selection uses a slit mask inside a bunch compressor to transform the energy-chirped electron beam into a bunch train. The flat beam transformation boosts the frequency range of the THz source by reducing the beam emittance in one plane. This technique generates narrow-band THz radiation with a tuning range between 0.2 - 4 THz. Single frequency THz spectrum can also be generated by properly choosing the slit spacing, slit width, and the energy chirp.

physics.acc-ph↗
arXiv2013

First experimental research of low energy proton radiography

Proton radiography is a new scatheless diagnostic tool, and which provides a potential development direction for advanced hydrotesting. Recently a low energy proton radiography system has been developed at CAEP. This system has been designed to use 11MeV proton beam to radiograph thin static objects. This system consists of a proton cyclotron coupled to an imaging beamline. The design features and commissioning results of this radiography system are presented.

physics.acc-ph↗
arXiv2013

Bright gamma-rays from betatron resonance acceleration in near critical density plasma

We show that electron betatron resonance acceleration by an ultra-intense ultra-short laser pulse in a near critical density plasma works as a high-brightness gamma-ray source. Compared with laser plasma X-ray sources in under-dense plasma, near critical density plasma provides three benefits for electron radiation: more radiation electrons, larger transverse amplitude, and higher betatron oscillation frequency. Three-dimensional particle-in-cell simulations show that, by using a 7.4J laser pulse, 8.3mJ radiation with critical photon energy 1MeV is emitted. The critical photon energy $E_c$ increases with the incident laser energy %faster than a linear relation. $W_I$ as $E_c \propto W_I^{1.5}$, and the corresponding photon number is proportional to $W_I$. A simple analytical synchrotron-like radiation model is built, which can explain the simulation results.

physics.acc-ph↗
arXiv2013

Tau/Charm Factory Accelerator Report

The present Report concerns the current status of the Italian Tau/Charm accelerator project and in particular discusses the issues related to the lattice design, to the accelerators systems and to the associated conventional facilities. The project aims at realizing a variable energy Flavor Factory between 1 and 4.6 GeV in the center of mass, and succeeds to the SuperB project from which it inherits most of the solutions proposed in this document. The work comes from a cooperation involving the INFN Frascati National Laboratories accelerator experts, the young newcomers, mostly engineers, of the Cabibbo Lab consortium and key collaborators from external laboratories.

physics.acc-ph↗
arXiv2013

Snowmass 2013 Computing Frontier: Intensity Frontier

The Intensity Frontier (IF) is a primary focus of the U.S.-based particle physics program. It encompasses a large spectrum of physics, including quark flavor physics, charged lepton processes, neutrinos, baryon number violation, new light weakly-coupled particles, and nucleons, nuclei and atoms. There are many experiments, a range of scales in data output and throughput, and a wide range in the number of experimenters. The experiments, projects and theory in this area all require demanding computing capabilities and technologies. The IF experiments have significant computing requirements for simulation, theory and modeling, beam line and experiment design, triggers and DAQ, online monitoring, event reconstruction and processing, and physics analysis. We have conducted a qualitative survey of the current and near-term future experiments in the IF to understand the computing demands of this area and their expected evolution. This report details the expected computing requirements for the IF in the context of the Snowmass Community Summer Study 2013.

hep-ex↗
arXiv2013

A gaseous stripper proposal based on hadrontherapy facility HIMM

Multi-turn Injection scheme with gaseous stripper is usually used in high intensity and super heavy ion injection process. With its advantage of long lifetime and uniformity, a gaseous stripper is proposed based on the under construction hadrontherapy facility HIMM (Heavy Ion Medical Machine). In this paper, the physical process between the injecting beam and the gaseous target is studied, and a simulation work is conducted based on the former developed code.

physics.acc-ph↗
arXiv2013

Analysis of post wet chemistry heat treatment effects on Nb SRF surface resistance

Most of the current research in superconducting radio frequency (SRF) cavities is focused on ways to reduce the construction and operating cost of SRF based accelerators as well as on the development of new or improved cavity processing techniques. The increase in quality factors is the result of the reduction of the surface resistance of the materials. A recent test on a 1.5 GHz single cell cavity made from ingot niobium of medium purity and heat treated at 1400 C in a ultra-high vacuum induction furnace resulted in a residual resistance of about 1nanoohm and a quality factor at 2.0 K increasing with field up to 5x10^10 at a peak magnetic field of 90 mT. In this contribution, we present some results on the investigation of the origin of the extended Q0-increase, obtained by multiple HF rinses, oxypolishing and heat treatment of all Nb cavities.

physics.acc-ph↗
arXiv2013

On the Electromagnetic Design of a Beta_g= 0.61, 650 MHz Superconducting Radiofrequency Cavity

We present the calculations for electromagnetic design of a Beta_g = 0.61, multi-cell superconducting radiofrequency cavity for the Indian Spallation Neutron Source (ISNS) project. Geometry of the mid-cells is optimized using a step by step, one-dimensional optimization technique. This is followed by the optimization of end-cells, which is done to achieve the required field flatness, as well as to avoid trapping of higher order modes. Calculations of the threshold beam current for the excitation of regenerative beam break up instability excited by the dipole modes is also presented, which is followed by wake field calculations and estimation of its effects. Specific aspects relevant to design calculations for medium Beta_g cavities, compared to high Beta_g cavities are highlighted in the paper. Finally, studies are performed for the static as well as dynamic Lorentz Force Detuning (LFD), based on which the stiffness design of the cavity is optimized.

physics.acc-ph↗
arXiv2013

Feasibility Study on SRF Cavity Improvement by Doping Method

In this article a new idea is proposed by PKU group to improve the RF superconductive property of niobium cavity. Rare earth elements like scandium and yttrium are doped into ingot niobium during the smelting processes. A series of experiments have been done since 2010, and the preliminary testing results show that the magnetic property of niobium materials has been changed with different doping elements and proportions while the superconductive transition temperature almost does not change. Then a large ingot niobium doped with scandium was melted. RRR and mechanical properties were measured. This method may increase the superheating magnetic field and decrease surface resistance of niobium so as to improve the performance of niobium cavity which is a key component of SRF accelerators. A single-cell cavity made of Sc-doped niobium has been fabricated.

physics.acc-ph↗
arXiv2013

Conditioning of BPM pickup signals for operations of the Duke storage ring with a wide range of single-bunch current

The Duke storage ring is a dedicated driver for the storage ring based oscillator free-electron lasers (FELs), and the High Intensity Gamma-ray Source (HIGS). It is operated with a beam current ranging from about 1 mA to 100 mA per bunch for various operations and accelerator physics studies. High performance operations of the FEL and gamma-ray source require a stable electron beam orbit, which has been realized by the global orbit feedback system. As a critical part of the orbit feedback system, the electron beam position monitors (BPMs) are required to be able to precisely measure the electron beam orbit in a wide range of the single-bunch current. However, the high peak voltage of the BPM pickups associated with high single-bunch current degrades the performance of the BPM electronics, and can potentially damage the BPM electronics. A signal conditioning method using low pass filters is developed to reduce the peak voltage to protect the BPM electronics, and to make the BPMs capable of working with a wide range of single-bunch current. Simulations and electron beam based tests are performed. The results show that the Duke storage ring BPM system is capable of providing precise orbit measurements to ensure highly stable FEL and HIGS operations.

physics.acc-ph↗
arXiv2013

About_the_electrodynamic_acceleration_of_cylinder-shaped_particles

A possibility of electrodynamic acceleration of particles from the initial zero velocity to the final velocity ten kilometeres per second the acceleration length five meters is considered. After the electrostatic preacceleration particles are accelerated at the trailing edge of the voltage pulse six megavolts, which runs along the spiral turns. Accelerated particles have the diameter six microns, and length one centimeter. Because of a pointed cone at the head the particles can move in the air almost without loss of velocity, penetrating into aluminum and water as deep as ten centimeter and water one meter respectively.

physics.acc-ph↗
arXiv2013

Different Charges in the Same Bunch Train at the European XFEL

In this paper we have investigated the possibility of the operation of different charges in the bunch train for the nominal design of the XFEL injector and for the case that it is extended by an additional laser system on the cathode. We have examined the problem of similarity of beam optical functions for different bunch charges in a train. We report also about the sensitivity of the beam optical functions on the chosen compression scenario and give an overview over the working points for the settings at the injector for single charge operation as well as combined working points for different bunch pairs.

physics.acc-ph↗
arXiv2013

Potential of a longitudinally focusing insertion for a storage ring X-ray FEL

In present work we investigate the potential of a longitudinally focusing device to compress bunches passing an undulator for a synchrotron storage ring. If integrated into a storage ring similar to PETRAIII such device could potentially produce continuous $\sim$1ps pulses of photons in the $nm$ range with peak pulse powers of tens of GW. Even without operating in FEL saturation mode the longitudinal focusing can provide means to increase the brightness and shorten the photon pulse length.

physics.acc-ph↗
arXiv2013

Multi- Physics analysis of the RFQ for the Injector Scheme II of CADS Driver Linac

A 162.5 MHz, 2.1 MeV Radio Frequency Quadruples (RFQ) structure is being designed for the Injector Scheme II of China Accelerator Driver System (CADS) driver linac. The RFQ will operate at continuous wave (CW) mode as required. For the CW normal conducting machine, the heat management will be one of the most important issues, since the temperature fluctuation may cause cavity deformation and leading to the resonant frequency shift. Therefor a detailed multi-physics analysis is necessary to ensure that the cavity can be stably worked at the required power level. The multi-physics analysis process includes RF Electromagnetic analysis, Thermal analysis, Mechnical analysis, and this process will be iterated for several cycles until the satisfied solution can be found. As one of the widely accepted measures, the cooling water system is used for frequency fine tunning, so the tunning capability of the cooling water system is also studied at different conditions. The results indicate that with the cooling water system, both the temperature rise and the frequency shift can be controlled in an acceptable level.

physics.acc-ph↗
arXiv2013

Generating of short pulses with high amplitudes by using of standard Current-Feedback-Amplifier

The traditional method to generate pulses in the range of some nanoseconds with high amplitudes, is the using of the avalanche-effect of transistors. However the problem with this method is the poor possibility for parameterizing. That was the trigger to look for a different way: under using of modern electronic components, a pulse generator, which is parameterizable, was developed. The parameters can be set by using a Windows- or Linux-PC. The pulse width can be adjusted in the range of 3....80 ns; the pulse amplitude in the range of 18...84 V and the pulse repetition rate in the range of 1 Hz to 50 kHz.

physics.ins-det↗
arXiv2013

Neutrino Factory R&D Efforts

Stored-muon-beam neutrino factories have been recognized as the best option to measure precisely the elements of the MNSP matrix and sensitively test the consistency of the three-neutrino mixing picture. Now that all three mixing angles have been shown to be nonzero, the motivation for neutrino factory construction is strong. A small number of feasibility issues remain open and are the subject of ongoing R&D. Progress on these R&D efforts is described.

physics.acc-ph↗