9738861
Proposal for PLASMA LENS EXPEFUMENTS AT THE FINAL FOCUS TEST BEAM
We intend to carry out a series of plasma lens experiments at the Final Focus Test Beam facility at SLAC. These experiments will be the first to study the focusing of particle beams by plasma focusing devices in the parameter regime of interest for high energy colliders, and is expected to lead to plasma lens designs capable of unprecedented spot sizes. Plasma focusing of positron beams will be attempted for the first time. WC will study the effects of lens aberrations due to various lens imperfections. Several approaches will be applied to create the plasma required including laser ionization and beam ionization of a working gas. At an increased bunch population of 2.5 X IO’“, tunneling ionization of a gas target by an electron beam an effect which has never been observed bcforc should he significant. The compactness of our device should prove to be of interest for applications at the SLC and the next generation linear colliders.
51748746
Proposal for a one GeV plasma wakefield acceleration experiment at SLAC
Abstract A plasma-based wakefield acceleration experiment E-157 has been approved at SLAC to study acceleration of parts of an SLC bunch by up to 1 GeV/m over a length of 1 m. A single SLC bunch is used to both induce wakefields in the 1 m long plasma and to witness the resulting beam acceleration. The experiment will explore and further develop the techniques that are needed to apply high-gradient plasma wakefield acceleration to large-scale accelerators. The 1 m length of the experiment is about two orders of magnitude larger than for other high gradient plasma wakefield acceleration experiments and the 1 GeV/m accelerating gradient is roughly ten times larger than that achieved with conventional metallic structures. Using existing SLAC facilities, the experiment will study high gradient acceleration at the forefront of advanced accelerator research.
56152176
CEBAF-ER: Extending the Frontier of Energy Recovery at Jefferson Lab
A successful GeV scale energy recovery demonstration with a high ratio of peak-to-injection energies (50:1) was recently carried out on the CEBAF (Continuous Electron Beam Accelerator Facility) recirculating superconducting linear accelerator in an effort to address issues related to beam quality preservation in a large scale energy recovery system. To gain a quantitative understanding of the beam behavior through the machine, an intense effort was made to characterize the 6D phase space during the CEBAF-ER (CEBAF with Energy Recovery) experimental run. A scheme was implemented to measure the transverse emittance of the energy recovered beam prior to being sent to the dump, as well as in the injector and in each arc. The emittance provides a figure of merit in this context inasmuch as it characterizes the extent to which beam quality is preserved during energy recovery. In addition to describing the transverse phase space, the momentum spread was measured in the injector and arcs to characterize the longitudinal phase space. Measurements also included the RF system's response to the energy recovery process. And by using a novel technique employing wire scans in conjunction with PMTs (Photomultiplier Tubes) to accurately measure the beam profile at the dump, we can qualitativelymore » characterize beam preservation through the recirculator. One of the salient conclusions from the experiment is that the energy recovery process does not contribute to the emittance degradation since the emittance of the recirculating pass is consistent with that of the accelerating pass.« less
55285360
Optimization of the Parameters of a Storage Ring for a High Power XUV Free Electron Laser
In this paper we describe the operation of an XUV high gain FEL operating within a bypass of an electron storage ring, and discuss the implications on storage ring optimization imposed by FEL requirements. It transpires that, in the parameter regime of interest, collective effects within the beam play an important role. For example, intrabeam scattering dilutes the transverse emittance of the beam and the microwave instability increases the momentum spread. Both phenomena reduce the effectiveness of the FEL. A computer code, ZAP, has been written which, for a given lattice design, takes all such effects into consideration and produces a figure of merit for FEL operation for that machine. We show the results of ZAP for several storage ring designs, all optimized for FEL operation, and present a design example of a facility capable of producing coherent radiation at 400 Å with tens of megawatts of peak power.
55975443
Accelerator physics experiments at Aladdin
DISCLAIMER LBL--19905 DE86 005847 -J or un or _ames my 1epI liability or reaponli- bility for the accuracy com~ '. or usefuloeu or uy information, apparatus product, or r- _ _ _ _ or ~ts tbat Its UJe would not • I i · · eoce herein to any SpccUlC COOImercial oil ID nnse !, Ya!ely owned rishts. Refer- manufa<1urer, or othcr1¥ise does not PI' .~ pr~, or se~ by trade name, trademark, riI Y mendation, or favorinS by the United Go constItute or Imply its endorsement, recom- es veroment or an v agen thereof Th . e VIews a nd optDlODS of authors ex-..... b . d r'~ erelD 0 not necessarily late flee UDlted States Goveroment or any agency thereof. S or re t those of tbe or work IpOIIIOred b Gom-nmcnl Neilllcr Ik United St.tcs r _ _ y u aaency or the United States -- mUea any ......... ty exPRU JJDJc:nt DOl' uy .... .-~ thereof. or t heir cm.......-. . plied, DOl' any This n:port . . . prepm:d U .. _at ne;;::- ACCELERATOR PHYSICS EXPERIMENTS AT ALADDIN* S. Chattopadhyay, K. Cornacchia, A. Jackson, and K.S. Zisman Lawrence Berkeley Laboratory University of California Berkeley, California 94720 July 1985 This work vas partiaUy supported by the Direcloc-. Office of Enct'yllcl wlib ft.M IlJ.S. hH
124556579
Motivation and goals of ERL 2005
Various types of ERL sources are introduced, the relevant beam physics and accelerator technology issues noted, innovative areas of development identified and current and future goals of ERL research and development established.
119545056
A study on the role of f(G) gravity on the emergent universe
Motivated by the recent work of Rastkar et al. (in Astrophys. Space Sci. 337:487, 2012) the present study has attempted to study the role of f(G) gravity in the emergent universe. Different energy conditions are examined for the effective energy density and violation of strong energy condition is observed. Also, the behavior of the equation of state parameter is studied for the effective energy density and dark energy density. It is found that the equation of state parameter behaves like phantom in both of the cases.
119194879
Can holographic dark energy increase the mass of the wormhole?
Motivated by the quantum essence of wormholes, in this work, we have studied accretion of dark energy (DE) onto Morris–Thorne wormhole with three different forms, namely, holographic dark energy, holographic Ricci dark energy and modified holographic Ricci dark energy. Considering the scale factor in power-law form we have observed that as the holographic dark energy accretes onto wormhole, the mass of the wormhole is decreasing. In the next phase we considered three parameterization schemes that are able to get hold of quintessence as well as phantom phases. Without any choice of scale factor we reconstructed Hubble parameter from conservation equation and dark energy densities and subsequently got the mass of the wormhole separately for accretion of the three dark energy candidates. It was observed that if these dark energies accrete onto the wormhole, then for quintessence stage, wormhole mass decreases up to a certain finite value and then again increases to aggressively during phantom phase of the universe.
54044861
Extended Holographic Ricci Dark Energy in Chameleon Brans-Dicke Cosmology
In the present work, we have studied some features of the generalized Brans-Dicke (BD) model in which the scalar field is allowed to couple nonminimally with the matter sector. Extended holographic Ricci dark energy (EHRDE) has been considered in the above framework 
of BD cosmology. Some restrictions have been derived for the BD parameter , and a stronger matter-chameleon coupling has been observed with the expansion of the universe. In this framework, the equation of the state parameter of EHRDE has behaved like quintom. Also, we have reconstructed the potential and coupling function for BD model for the EHRDE. It has been observed that the potential function is increasing as the matter-chameleon coupling is getting stronger.
56560251
A Study on the Interacting Ricci Dark Energy in f(R, T) Gravity
The present work reports study on the interacting Ricci dark energy in a modified gravity theory named f(R, T) gravity. In the specific model f(R, T) = μR + νT we have observed a quintom-like behavior of the equation of state parameter and a transition from matter dominated to dark energy density has been observed through fraction density evolution. The statefinder parameters reveal that the model interpolates between dust and $$\Uplambda\hbox{CDM}$$ΛCDM phases of the universe.
119883814
Anomalous increase in width of fission-fragment mass distribution as a probe for onset of quasifission reactions in deformed target-projectile system at near and sub-barrier energies
Fission-fragment mass distribution has been studied for the {sup 16}O+{sup 232}Th,{sup 209}Bi systems over an energy range of 102.8-78.6 MeV and 81.6-72.6 MeV, respectively, in a laboratory frame. The variance of the mass distribution ({sigma}{sub m}{sup 2}) for the {sup 16}O+{sup 209}Bi system varies linearly with center of mass energy, while a significant anomalous behavior is found for the system {sup 16}O+{sup 232}Th. Coupled with our earlier observation for the system {sup 19}F+{sup 232}Th [T. K. Ghosh et al., Phys. Rev. C 69, 031603(R) (2004)], we propose that the accurate measurement of mass distribution is a powerful tool to look for the onset of a nonstatistical reaction mechanism in heavy-ion-induced fission of deformed heavy nuclei.