FEL2019 - List of Authors (Jia, Q.K.)

Paper	Title	Page
MOA07	Commissioning and First Lasing of the FELiChEM: A New IR and THz FEL Oscillator in China	15
	H.T. Li, Q.K. Jia USTC/NSRL, Hefei, Anhui, People’s Republic of China
	A new infrared FEL named FELiChEM aiming at the energy chemistry has been constructed and commissioned at NSRL in Hefei. It consists of two FEL oscillators driven by one normal-conducting S-Band linac with maximum beam energy of 60 MeV. The two oscillators generate the midinfrared and far-infrared lasers covering the spectral range of 2.5-50 µm and 40-200 µm, respectively. First lasing was achieved at a wavelength of 15 µm with an electron energy of 35 MeV. Till now, we have observed the FEL signal from 3.5 µm to 30 µm and achieved the maximum micropulse energy up to 27 µJ at 15 µm.
	Slides MOA07 [2.434 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-MOA07
About •	paper received ※ 20 August 2019 paper accepted ※ 28 August 2019 issue date ※ 05 November 2019
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TUP047	An Analysis of Optimal Initial Detuning for Maximum Energy-Extraction Efficiency	145
	Q.K. Jia USTC/NSRL, Hefei, Anhui, People’s Republic of China
	For low gain free electron laser (FEL), the phase space evolutions of trapped electrons in the phase bucket are analyzed through calculating their synchrotron oscillation periods, which vary with the initial detuning and initial phase. The optimal initial detuning for the maximum energy-extraction efficiency and the corresponding saturation length are given. The analysis demonstrated that for the low gain case the gain of the strong optical field is about a quarter of that of the weak optical field (small signal gain), and the saturation power larger than that of high gain FEL can be achieved in the resonator of oscillator FEL.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP047
About •	paper received ※ 19 August 2019 paper accepted ※ 27 August 2019 issue date ※ 05 November 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEP063	The Preliminary Study of a Pre-Bunched Terahertz Free Electron Laser by a Velocity Bunching Scheme	477
	R. Huang, Q.K. Jia, H.T. Li, Z. Zhao USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Funding: Work supported by the National Natural Science Foundation of China Grant Number 11805200 Terahertz (THz) radiation has broad applications in biological sciences, materials imaging and radar communications and so on. High-power, frequency-adjustable THz radiation sources are desired. An electron beam, generated in a photoinjector and bunched at terahertz (THz) frequency, will excite a coherent THz radiation when entering an undulator. The radiation power mainly depends on the particle number and the bunching factor of the electron beam, which is limited by the space charge effect among the microbunches and the total rf phase width the macrobunch occupied. Previously we have designed a pre-bunched THz free electron laser (FEL) with the radiation frequency covering 0.5-5 THz. While the radiation intensity for the lower frequency (below 1~THz) is not very high because of the large energy spread and the low bunching factor. We will report a THz FEL by a velocity bunching scheme, which could realize more highly bunched beam especially in the low THz frequency region. The physical design of the electron source is described in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-WEP063
About •	paper received ※ 19 August 2019 paper accepted ※ 28 August 2019 issue date ※ 05 November 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Commissioning and First Lasing of the FELiChEM: A New IR and THz FEL Oscillator in China

15

H.T. Li, Q.K. Jia
USTC/NSRL, Hefei, Anhui, People’s Republic of China

A new infrared FEL named FELiChEM aiming at the energy chemistry has been constructed and commissioned at NSRL in Hefei. It consists of two FEL oscillators driven by one normal-conducting S-Band linac with maximum beam energy of 60 MeV. The two oscillators generate the midinfrared and far-infrared lasers covering the spectral range of 2.5-50 µm and 40-200 µm, respectively. First lasing was achieved at a wavelength of 15 µm with an electron energy of 35 MeV. Till now, we have observed the FEL signal from 3.5 µm to 30 µm and achieved the maximum micropulse energy up to 27 µJ at 15 µm.

Slides MOA07 [2.434 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-MOA07

About •

paper received ※ 20 August 2019 paper accepted ※ 28 August 2019 issue date ※ 05 November 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP047

An Analysis of Optimal Initial Detuning for Maximum Energy-Extraction Efficiency

145

Q.K. Jia
USTC/NSRL, Hefei, Anhui, People’s Republic of China

For low gain free electron laser (FEL), the phase space evolutions of trapped electrons in the phase bucket are analyzed through calculating their synchrotron oscillation periods, which vary with the initial detuning and initial phase. The optimal initial detuning for the maximum energy-extraction efficiency and the corresponding saturation length are given. The analysis demonstrated that for the low gain case the gain of the strong optical field is about a quarter of that of the weak optical field (small signal gain), and the saturation power larger than that of high gain FEL can be achieved in the resonator of oscillator FEL.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP047

About •

paper received ※ 19 August 2019 paper accepted ※ 27 August 2019 issue date ※ 05 November 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEP063

The Preliminary Study of a Pre-Bunched Terahertz Free Electron Laser by a Velocity Bunching Scheme

477

R. Huang, Q.K. Jia, H.T. Li, Z. Zhao
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Funding: Work supported by the National Natural Science Foundation of China Grant Number 11805200
Terahertz (THz) radiation has broad applications in biological sciences, materials imaging and radar communications and so on. High-power, frequency-adjustable THz radiation sources are desired. An electron beam, generated in a photoinjector and bunched at terahertz (THz) frequency, will excite a coherent THz radiation when entering an undulator. The radiation power mainly depends on the particle number and the bunching factor of the electron beam, which is limited by the space charge effect among the microbunches and the total rf phase width the macrobunch occupied. Previously we have designed a pre-bunched THz free electron laser (FEL) with the radiation frequency covering 0.5-5 THz. While the radiation intensity for the lower frequency (below 1~THz) is not very high because of the large energy spread and the low bunching factor. We will report a THz FEL by a velocity bunching scheme, which could realize more highly bunched beam especially in the low THz frequency region. The physical design of the electron source is described in detail.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-WEP063

About •

paper received ※ 19 August 2019 paper accepted ※ 28 August 2019 issue date ※ 05 November 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)