In general, high energy density matter can only be transiently produced in the laboratory on a time scale ofnanoseconds. In addition, the pressure in a high energy density sample exceeds 1 Mbar, thus the hydro-dynamic...In general, high energy density matter can only be transiently produced in the laboratory on a time scale ofnanoseconds. In addition, the pressure in a high energy density sample exceeds 1 Mbar, thus the hydro-dynamicresponse of the sample is a high expansion velocity in the range of km/s (or m/ns). Therefore diagnostics whichare capable of high time resolution (< ns) and high space resolution (< 10 m) are needed. Here, we present ascheme that uses a high energy electron beam as a probe for dynamic imaging measurements of high energy densityprocesses in materials with spatial, temporal resolution and frame rate in the order of 1 m, 1 ps and 1010 FPS,respectively.The device uses an e-LINAC (electron Linear Accelerator), which can produce electron beams with bunchintensity ranging from a few pC to 100 nC, bunch length and bunch interval of 1 and 100 ps in minimum, respectively.The beam energy can be increased easily from a few MeV to GeV by adding more accelerating sections. Detailscan be found in Ref. [1].展开更多
Tunable and compact high power terahertz (THz) radiation based on coherent radiation (CR) of the picosecond relativistic electron bunch train is under development at the Tsinghua accelerator lab. Coherent synchronizat...Tunable and compact high power terahertz (THz) radiation based on coherent radiation (CR) of the picosecond relativistic electron bunch train is under development at the Tsinghua accelerator lab. Coherent synchronization radiation (CSR) and coherent transition radiation (CTR) are researched based on an S-band compact electron linac, a bending magnet or a thin foil. The bunch train's form factors, which are the key factor of THz radiation, are analyzed by the PARMELA simulation. The effects of electron bunch trains under different conditions, such as the bunch number, bunch charges, micro-pulses inter-distance, and accelerating gradient of the gun are investigated separately in this paper. The optimal radiated THz power and spectra should take these factors as a whole into account.展开更多
A compact C-band high brightness photoinjector for ultra-fast electron diffraction(UED)is under development at Tsinghua University.The C-band photoinjector,operating at 5.172 GHz,uses a 1.45-cell C-band RF gun as the ...A compact C-band high brightness photoinjector for ultra-fast electron diffraction(UED)is under development at Tsinghua University.The C-band photoinjector,operating at 5.172 GHz,uses a 1.45-cell C-band RF gun as the electron source.The design of the RF gun has addressed the physics,beam dynamics and mechanical aspects,and based on these design studies,a prototype has been fabricated.In order to obtain optimized performance for the UED,beam dynamics simulation has been carried out using the particle tracking code Astra for the photoinjector consisting of an alternative multi-cell RF gun design and a C-band compressor downstream.The beam dynamics parameters that are optimized include the bunch length,peak current,horizontal emittance,and position of the minimum bunch length.展开更多
The radiation of high-gain short-wavelength free-electron laser depends on the slice transverse emittance of the electron bunch. This essay introduces the method of slice emittance measurement, and shows the brief set...The radiation of high-gain short-wavelength free-electron laser depends on the slice transverse emittance of the electron bunch. This essay introduces the method of slice emittance measurement, and shows the brief setup of this experiment using the solenoid scanning and RF deflecting cavity at Tsinghua University. The preliminary experimental results show that the slice rms emittance of the electron bunch generated by photocathode RF gun has considerable variations along the bunch and is typically less than 0.55 mm mrad for the laser rms radius of 0.4 mm.展开更多
基金National Natural Science Foundation of China (1435015, 11275241)
文摘In general, high energy density matter can only be transiently produced in the laboratory on a time scale ofnanoseconds. In addition, the pressure in a high energy density sample exceeds 1 Mbar, thus the hydro-dynamicresponse of the sample is a high expansion velocity in the range of km/s (or m/ns). Therefore diagnostics whichare capable of high time resolution (< ns) and high space resolution (< 10 m) are needed. Here, we present ascheme that uses a high energy electron beam as a probe for dynamic imaging measurements of high energy densityprocesses in materials with spatial, temporal resolution and frame rate in the order of 1 m, 1 ps and 1010 FPS,respectively.The device uses an e-LINAC (electron Linear Accelerator), which can produce electron beams with bunchintensity ranging from a few pC to 100 nC, bunch length and bunch interval of 1 and 100 ps in minimum, respectively.The beam energy can be increased easily from a few MeV to GeV by adding more accelerating sections. Detailscan be found in Ref. [1].
基金supported by the National Natural Science Foundation of China (Grant No. 10975088)
文摘Tunable and compact high power terahertz (THz) radiation based on coherent radiation (CR) of the picosecond relativistic electron bunch train is under development at the Tsinghua accelerator lab. Coherent synchronization radiation (CSR) and coherent transition radiation (CTR) are researched based on an S-band compact electron linac, a bending magnet or a thin foil. The bunch train's form factors, which are the key factor of THz radiation, are analyzed by the PARMELA simulation. The effects of electron bunch trains under different conditions, such as the bunch number, bunch charges, micro-pulses inter-distance, and accelerating gradient of the gun are investigated separately in this paper. The optimal radiated THz power and spectra should take these factors as a whole into account.
文摘A compact C-band high brightness photoinjector for ultra-fast electron diffraction(UED)is under development at Tsinghua University.The C-band photoinjector,operating at 5.172 GHz,uses a 1.45-cell C-band RF gun as the electron source.The design of the RF gun has addressed the physics,beam dynamics and mechanical aspects,and based on these design studies,a prototype has been fabricated.In order to obtain optimized performance for the UED,beam dynamics simulation has been carried out using the particle tracking code Astra for the photoinjector consisting of an alternative multi-cell RF gun design and a C-band compressor downstream.The beam dynamics parameters that are optimized include the bunch length,peak current,horizontal emittance,and position of the minimum bunch length.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10735050, 10805031, 10875070 and 10925523)the National Basic Research Program of China (Grant No. 2007CB815102)the Tsinghua University Initiative Scientific Research Program
文摘The radiation of high-gain short-wavelength free-electron laser depends on the slice transverse emittance of the electron bunch. This essay introduces the method of slice emittance measurement, and shows the brief setup of this experiment using the solenoid scanning and RF deflecting cavity at Tsinghua University. The preliminary experimental results show that the slice rms emittance of the electron bunch generated by photocathode RF gun has considerable variations along the bunch and is typically less than 0.55 mm mrad for the laser rms radius of 0.4 mm.
