摘要:

©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1401555

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

This report summarizes the discussions help by Group II of the ICFA Advanced Beam Dynamics Workshop calledFuture Light Sources, Physics of, and Science with, the X-ray Free-Electron Laser. It starts with a discussion of several experiments which will benefit from the high intensity and the short pulses of the proposed XFEL beams. The choice of these experiments reflects the interests of the participants and the proposed sets of first experiments to be done with the XFEL. The second section discusses some of the instrumentation and optics issues that arise because of these experiments. The final section lists a set of topics that need active research and development in order to fully utilize these sources. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1401556

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

Femtosecond S-band linac with the BNL/GUN IV of Nuclear Engineering Research Laboratory, University of Tokyo, has recorded 240fs(FWHM), 6 pai mm. mrad(rms), 350pC/bunch. Maximum charge per bunch at the exit of the injector and QE were 7nC and1.5×10−4,respectively. After the cathode damage was found, re-measured emittance was 20 pai mm. mrad. Timing jitter between the femtosecond electron bunch and the drive laser for the injector was 330fs for the minutes and 1.9ps for hours. Detailed of the system are described, including the electron bunch diagnosis system. Further, the plasma gun work to produce 10fs, 20 MeV electron single bunch without any timing jitter is also mentioned. Those date and information give important mile stones for development of future SASE-FEL including LCLS. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1401557

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

In this paper we describe an electron beam collimator for the Linac Coherent Light Source. The collimator reduces both the transverse emittance and the total charge of the electron beam. Beam optics are designed to increase the beam spot size for collimation. The impedance of the collimator is calculated, and the wakefield induced emittance growth is determined. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1401558

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

The problem of the wake field generated by a relativistic particle travelling in a long beam pipe with rough surface has been revisited by means of a standard theory based on the hybrid modes excited in a periodically corrugated waveguide with circular cross section. Slow waves synchronous with the particle can be excited in the structure, producing wake fields whose frequency and amplitude depend on the depth of the corrugation. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1401559

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

The construction of a short pulse tunable x-ray laser source will be a watershed for plasma-based and warm dense matter research. The areas we will discuss below can be separated broadly into warm dense matter (WDM) research, laser probing of near solid density plasmas, and laser-plasma spectroscopy of ions in plasmas. The area of WDM refers to that part of the density-temperature phase space where the standard theories of condensed matter physics and/or plasma statistical physics are invalid. Warm dense matter, therefore, defines a region between solids and plasmas, a regime that is found in planetary interiors, cool dense stars, and in every plasma device where one starts from a solid,e.g., laser-solid matter produced plasma as well as all inertial fusion schemes. The study of dense plasmas has been severely hampered by the fact that laser-based methods have been unavailable. The single most useful diagnostic of local plasma conditions,e.g., the temperature(Te),the density(ne),and the ionization(Z),has been Thomson scattering. However, due to the fact that visible light will not propagate at electron densities,ne⩾1022&hthinsp;cm−3implies dense plasmas can not be probed. The 4th generation sources, LCLS and Tesla will remove these restrictions. Laser-based plasma spectroscopic techniques have been used with great success to determine the line shapes of atomic transitions in plasmas, study the population kinetics of atomic systems embedded in plasmas, and look at redistribution of radiation. However, the possibilities end for plasmas withne⩾1022since light propagation through the medium is severely altered by the plasma. The entire field of highZplasma kinetics from laser produced plasma will then be available to study with the tunable source. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1401560

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

The energy spread of particles inside a short bunch propagating along the co-axial channel with small random axially-symmetric wall perturbations is calculated. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1401561

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

Magnetic field characteristics of two novel hybrid undulator schemes are given. The undulators were specially designed to be adequate to the X-ray FEL project LCLS. It is demonstrated that using these novel schemes the high specified magnetic field strengths can be obtained at larger gaps than with any other known hybrid undulator scheme. Basic field parameters are given for the planar and the helical hybrid undulators with the specified period 3 cm. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1401562

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

A SASE mode FEL evolution starting from noise was simulated using an 1D code. Temporal and space structure of the optical pulse as well as the electron bunch were numerically studied. New possible effects from slowing down of spikes and from phase jumps of the optical pulse were investigated. It is shown that slowing down of the spikes before saturation takes place can enhance the output field intensity by 10&percent;. Along with this a phase jump near the saturation depth can give intensity increasing by 50&percent;. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1401563

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

We describe here a new method to increase the peak current of high brightness electron beams as those required to drive X-ray SASE FEL’s, that is based on a rectilinear compressor scheme utilizing the bunching properties of slow waves. It is shown that whenever a beam, slower than the synchronous velocity, is injected into a RF wave at the zero acceleration phase and slips back in phase up to the peak acceleration phase, it can be compressed as far as the extraction happens at the synchronous velocity. In fact, the bunch undergoes a quarter of synchrotron oscillation that induces a net compression (i.e. a bunch length reduction) up to a factor of 20 when proper care is taken to preserve the longitudinal emittance. A few examples are presented to demonstrate the potentialities of this method, by which multi-kA beams at very low emittance can be generated at moderate energies (about 100 MeV). ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1401564

出版商:AIP    

年代:1901

数据来源: AIP