A new kind of electron source, the photoemissive monoenergetic electron source has been invented for calibrating the beta--magnetic spectrometer. It produceselectrons in the form of simulating a radioactive monoenerge...A new kind of electron source, the photoemissive monoenergetic electron source has been invented for calibrating the beta--magnetic spectrometer. It produceselectrons in the form of simulating a radioactive monoenergetic electron source andcan be made in any shape and size according tO the demands of experimentS. In thispaper, the principles and basic constructions of the photoemissive monoenergeticelectron source are described, the resultS of calibrating our 2’l’x bead--magneticspectrometer with a single strip arc shaped photoemissive monoenergetic electronsource are listed, a new way for determining resolution function of experimentslsystem in the research of neutrino rest mass has been posed and one of its actualapplications is also given.展开更多
We present analytical studies of electron acceleration in the low-density preplasma of a thin solid target byan intense femtosecond laser pulse.Electrons in the preplasma are trapped and accelerated by the ponderomoti...We present analytical studies of electron acceleration in the low-density preplasma of a thin solid target byan intense femtosecond laser pulse.Electrons in the preplasma are trapped and accelerated by the ponderomotive forceas well as the wake field.Two-dimensional particle-in-cell simulations show that when the laser pulse is stopped by thetarget,electrons trapped in the laser pules can be extracted and move forward inertially.The energetic electron bunchin the bubble is unaffected by the reflected pulse and passes through the target with small energy spread and emittance.There is an optimal preplasma density for the generation of the monoenergetic electron bunch if a laser pulse is given.The maximum electron energy is inverse proportion to the preplasma density.展开更多
The wake bubble expansion and contraction by adding a dense-plasma wall in the background plasma during the mode transition from laser wakefield to plasma wakefield accel- eration is investigated by particle-in-cell s...The wake bubble expansion and contraction by adding a dense-plasma wall in the background plasma during the mode transition from laser wakefield to plasma wakefield accel- eration is investigated by particle-in-cell simulations. The electrons are injected continuously into the cavity until the lateral bubble size equals the inner diameter of the wall. The injected electron bunch from the laser wakefield acceleration (LWFA) scheme is quasi phase-stably accel- erated forward because of the longitudinal contraction of the bubble. After the laser pulse is depleted completely, the electron bunch generated from the LWFA scheme drives a plasma wake- field. The electrons remaining in the channel are trapped and accelerated by the plasma wakefield. Ultimately, two energetic electron bunches with a narrow energy spread and low emittance are obtained.展开更多
文摘A new kind of electron source, the photoemissive monoenergetic electron source has been invented for calibrating the beta--magnetic spectrometer. It produceselectrons in the form of simulating a radioactive monoenergetic electron source andcan be made in any shape and size according tO the demands of experimentS. In thispaper, the principles and basic constructions of the photoemissive monoenergeticelectron source are described, the resultS of calibrating our 2’l’x bead--magneticspectrometer with a single strip arc shaped photoemissive monoenergetic electronsource are listed, a new way for determining resolution function of experimentslsystem in the research of neutrino rest mass has been posed and one of its actualapplications is also given.
基金Supported by the National Natural Science Foundation of China under Grant Nos.10875015,10834008,10963002the 973 Program under Grant No.2006CB806004Educational Commission of Jiangxi Province of China under Grant No.GJJ10052
文摘We present analytical studies of electron acceleration in the low-density preplasma of a thin solid target byan intense femtosecond laser pulse.Electrons in the preplasma are trapped and accelerated by the ponderomotive forceas well as the wake field.Two-dimensional particle-in-cell simulations show that when the laser pulse is stopped by thetarget,electrons trapped in the laser pules can be extracted and move forward inertially.The energetic electron bunchin the bubble is unaffected by the reflected pulse and passes through the target with small energy spread and emittance.There is an optimal preplasma density for the generation of the monoenergetic electron bunch if a laser pulse is given.The maximum electron energy is inverse proportion to the preplasma density.
基金supported by National Natural Science Foundation of China(Nos.11047152,11147005 and 11178002)The Natural Science Foundation of Jiangxi Province of China(Nos.2010GQW0048,20122BAB202003)
文摘The wake bubble expansion and contraction by adding a dense-plasma wall in the background plasma during the mode transition from laser wakefield to plasma wakefield accel- eration is investigated by particle-in-cell simulations. The electrons are injected continuously into the cavity until the lateral bubble size equals the inner diameter of the wall. The injected electron bunch from the laser wakefield acceleration (LWFA) scheme is quasi phase-stably accel- erated forward because of the longitudinal contraction of the bubble. After the laser pulse is depleted completely, the electron bunch generated from the LWFA scheme drives a plasma wake- field. The electrons remaining in the channel are trapped and accelerated by the plasma wakefield. Ultimately, two energetic electron bunches with a narrow energy spread and low emittance are obtained.