FEL2017 - List of Authors (Tischer, M.)

Paper	Title	Page
MOP031	First Operation of a Harmonic Lasing Self-Seeded FEL	102
	E. Schneidmiller, B. Faatz, M. Kuhlmann, J. Rönsch-Schulenburg, S. Schreiber, M. Tischer, M.V. Yurkov DESY, Hamburg, Germany
	Harmonic lasing is a perspective mode of operation of X-ray FEL user facilities that allows it to provide brilliant beams of higher-energy photons for user experiments. Another useful application of harmonic lasing is so called Harmonic Lasing Self-Seeded Free Electron Laser (HLSS FEL), that allows it to improve spectral brightness of these facilities. In the past, harmonic lasing has been demonstrated in the FEL oscillators in infrared and visible wavelength ranges, but not in high-gain FELs and not at short wavelengths. In this paper, we report on the first evidence of the harmonic lasing and the first operation of the HLSS FEL at the soft X-ray FEL user facility FLASH in the wavelength range between 4.5 nm and 15 nm. Spectral brightness was improved in comparison with Self-Amplified Spontaneous emission (SASE) FEL by a factor of six in the exponential gain regime. A better performance of HLSS FEL with respect to SASE FEL in the post-saturation regime with a tapered undulator was observed as well. The first demonstration of harmonic lasing in a high-gain FEL and at a short wavelength paves the way for a variety of applications of this new operation mode in X-ray FELs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP031
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MOP046	Progress of Delhi Light Source at IUAC, New Delhi	149
	S. Ghosh, S. R. Abhilash, R.K. Bhandari, G.K. Chaudhari, V.J. Joshi, D. Kabiraj, D. Kanjilal, B. Karmakar, J. Karmakar, N. Kumar, S. Kumar, A. Pandey, P. Patra, G.O. Rodrigues, B.K. Sahu, A. Sharma, S. Tripathi IUAC, New Delhi, India A. Aryshev, M.K. Fukuda, S. Fukuda, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan U. Lehnert, P. Michel HZDR, Dresden, Germany V. Naik, A. Roy VECC, Kolkata, India T. Rao BNL, Upton, Long Island, New York, USA M. Tischer DESY, Hamburg, Germany
	Funding: This project is jointly supported by Inter University Accelerator Center and Board of Research in Nuclear Science. The first phase of the pre-bunched FEL based on the Photoinjector RF electron gun, known as Delhi Light Source (DLS),* has been planned at Inter University Accelerator Centre (IUAC), New Delhi. The electron gun made from OFHC copper had already been fabricated and tested with low power RF at KEK, Japan. The beam optics calculation by using ASTRA, GPT codes has been performed and radiation produced from the pre-bunched electron bunches are being calculated. The high power RF systems will be commissioned at IUAC by the beginning of 2018. The design of the laser system is being finalized and assembly/testing of the complete laser system will be started soon at KEK. The initial design of the photocathode deposition mechanism has also been completed and its procurement/development process will start shortly. The first version of the undulator magnet design has been completed and further improvements are underway.* The initial arrangements of the DLS beam line have been worked out and various beam diagnostics components are being finalised. The production of the electron beam and THz radiation is expected by 2018 and 2019, respectively. * S. Ghosh et al., NIM-B, (2017) in press. V. Joshi et al., Proc. of this conference. * S. Tripathi et al., Proc. of this conference.
	Poster MOP046 [1.598 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP046
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WEP057	Design of a Compact Hybrid Undulator for the THz Radiation Facility of Delhi Light Source (DLS)	532
	S. Tripathi, R.K. Bhandari, S. Ghosh, D. Kanjilal IUAC, New Delhi, India U. Lehnert HZDR, Dresden, Germany M. Tischer DESY, Hamburg, Germany
	Funding: One author, Sumit Tripathi (PH/16-17/0029), would like to acknowledge University Grant Commission (UGC), New Delhi, India for financial support as D.S.Kothari Postdoctoral fellowship. A compact Free Electron Laser (FEL) facility to produce coherent THz radiation is in the development stage at Inter-University Accelerator Centre (IUAC), New Delhi, India.,* The name of this facility is Delhi Light Source (DLS) in which a low-emittance electron beam from a photocathode RF gun with a maximum energy of 8 MeV will be injected into a compact undulator magnet to generate THz radiation. To produce the THz radiation in the range of 0.15 to 3.0 THz, the electron beam energy and the undulator gap need to be varied from 4 to 8 MeV and 20 to 45 mm, respectively. The variable gap undulator of 1.5-m length will consist of NdFeB magnets with vanadium permendur poles. The magnet design and dimensions are optimised by using code 3D RADIA.*** The detailed design of the compact hybrid undulator will be presented in this paper. * S.Ghosh et al., presented at this conference. S.Ghosh et al., NIMB-2017 (in press). * RADIA. Available at http://www.esrf.eu/Accelerators/ groups/ Insertion Devices/ Software/ Radia.
	Poster WEP057 [1.117 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-WEP057
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Paper

Title

Page

First Operation of a Harmonic Lasing Self-Seeded FEL

102

E. Schneidmiller, B. Faatz, M. Kuhlmann, J. Rönsch-Schulenburg, S. Schreiber, M. Tischer, M.V. Yurkov
DESY, Hamburg, Germany

Harmonic lasing is a perspective mode of operation of X-ray FEL user facilities that allows it to provide brilliant beams of higher-energy photons for user experiments. Another useful application of harmonic lasing is so called Harmonic Lasing Self-Seeded Free Electron Laser (HLSS FEL), that allows it to improve spectral brightness of these facilities. In the past, harmonic lasing has been demonstrated in the FEL oscillators in infrared and visible wavelength ranges, but not in high-gain FELs and not at short wavelengths. In this paper, we report on the first evidence of the harmonic lasing and the first operation of the HLSS FEL at the soft X-ray FEL user facility FLASH in the wavelength range between 4.5 nm and 15 nm. Spectral brightness was improved in comparison with Self-Amplified Spontaneous emission (SASE) FEL by a factor of six in the exponential gain regime. A better performance of HLSS FEL with respect to SASE FEL in the post-saturation regime with a tapered undulator was observed as well. The first demonstration of harmonic lasing in a high-gain FEL and at a short wavelength paves the way for a variety of applications of this new operation mode in X-ray FELs.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP031

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MOP046

Progress of Delhi Light Source at IUAC, New Delhi

149

S. Ghosh, S. R. Abhilash, R.K. Bhandari, G.K. Chaudhari, V.J. Joshi, D. Kabiraj, D. Kanjilal, B. Karmakar, J. Karmakar, N. Kumar, S. Kumar, A. Pandey, P. Patra, G.O. Rodrigues, B.K. Sahu, A. Sharma, S. Tripathi
IUAC, New Delhi, India
A. Aryshev, M.K. Fukuda, S. Fukuda, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
U. Lehnert, P. Michel
HZDR, Dresden, Germany
V. Naik, A. Roy
VECC, Kolkata, India
T. Rao
BNL, Upton, Long Island, New York, USA
M. Tischer
DESY, Hamburg, Germany

Funding: This project is jointly supported by Inter University Accelerator Center and Board of Research in Nuclear Science.
The first phase of the pre-bunched FEL based on the Photoinjector RF electron gun, known as Delhi Light Source (DLS),* has been planned at Inter University Accelerator Centre (IUAC), New Delhi. The electron gun made from OFHC copper had already been fabricated and tested with low power RF at KEK, Japan. The beam optics calculation by using ASTRA, GPT codes has been performed and radiation produced from the pre-bunched electron bunches are being calculated.** The high power RF systems will be commissioned at IUAC by the beginning of 2018. The design of the laser system is being finalized and assembly/testing of the complete laser system will be started soon at KEK. The initial design of the photocathode deposition mechanism has also been completed and its procurement/development process will start shortly. The first version of the undulator magnet design has been completed and further improvements are underway.*** The initial arrangements of the DLS beam line have been worked out and various beam diagnostics components are being finalised. The production of the electron beam and THz radiation is expected by 2018 and 2019, respectively.
* S. Ghosh et al., NIM-B, (2017) in press.
** V. Joshi et al., Proc. of this conference.
*** S. Tripathi et al., Proc. of this conference.

Poster MOP046 [1.598 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP046

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WEP057

Design of a Compact Hybrid Undulator for the THz Radiation Facility of Delhi Light Source (DLS)

532

S. Tripathi, R.K. Bhandari, S. Ghosh, D. Kanjilal
IUAC, New Delhi, India
U. Lehnert
HZDR, Dresden, Germany
M. Tischer
DESY, Hamburg, Germany

Funding: One author, Sumit Tripathi (PH/16-17/0029), would like to acknowledge University Grant Commission (UGC), New Delhi, India for financial support as D.S.Kothari Postdoctoral fellowship.
A compact Free Electron Laser (FEL) facility to produce coherent THz radiation is in the development stage at Inter-University Accelerator Centre (IUAC), New Delhi, India.*,** The name of this facility is Delhi Light Source (DLS) in which a low-emittance electron beam from a photocathode RF gun with a maximum energy of 8 MeV will be injected into a compact undulator magnet to generate THz radiation. To produce the THz radiation in the range of 0.15 to 3.0 THz, the electron beam energy and the undulator gap need to be varied from 4 to 8 MeV and 20 to 45 mm, respectively. The variable gap undulator of 1.5-m length will consist of NdFeB magnets with vanadium permendur poles. The magnet design and dimensions are optimised by using code 3D RADIA.*** The detailed design of the compact hybrid undulator will be presented in this paper.
* S.Ghosh et al., presented at this conference.
** S.Ghosh et al., NIMB-2017 (in press).
*** RADIA. Available at http://www.esrf.eu/Accelerators/ groups/
Insertion Devices/ Software/ Radia.

Poster WEP057 [1.117 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-WEP057

Export •

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