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| 3. |
- Bahrdt, Johannes, et al.
(författare)
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Diagnostic Tools for the Undulator System of the Seeded HGHG-FEL at MAX-lab
- 2008
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Ingår i: Proceedings of FEL08. ; , s. 243-246
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Konferensbidrag (refereegranskat)abstract
- Within a collaboration between MAX-lab and BESSY a one stage seeded HGHG-FEL has been set up at Maxlab. BESSY has built the undulator system consisting of a modulator, a radiator and an electromagnetic chicane. BESSY has also installed three types of diagnostic tools: optical fibres for a fast Cherenkov beam loss detection, optical fibres for absolute dose measurements via their radiation-induced attenuation and THz detectors for the characterization of electron bunch properties. During first injections with a laser driven rf-gun the Cherenkov fibres have delivered detailed spatial information on the beam losses inside the beamline. Over the last year the second system, based on powermeter measurements, has detected a total dose of 180Gy. The high sensitivity and low drift of this system has been demonstrated. A THz detector behind the last dipole magnet close to the beam dump provides information on the bunch compression and the laser induced energy modulation. We report on the measurements performed with these diagnostics tools.
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| 5. |
- Batani, D., et al.
(författare)
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Effects of laser prepulse on proton generation
- 2010
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 620:1, s. 76-82
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Konferensbidrag (refereegranskat)abstract
- Low-intensity laser prepulse ( < 10(13) W/cm(2), ns duration) are a major issue in experiments on laser-generation of protons, often limiting the performances of proton sources produced by high-intensity lasers (approximate to 10(19) W/cm(2), ps or fs duration) Several effects are associated to the prepulse and are discussed in this contribution: i) Destruction of thin foil targets by the shock generated by the laser prepulse ii) Creation of preplasma on target front side affecting laser absorption iii) Deformation of target rear side iv) Whole displacement of thin foil targets affecting focusing condition In particular, we show that under oblique high-intensity irradiation and for low prepulse intensities, the proton beam is directed away from the target normal. Deviation is towards the laser forward direction, with an angle that increases with the level and duration of the ASE pedestal. Also, for a given laser pulse, beam deviation increases with proton energy. The observations are discussed in terms of Target Normal Sheath Acceleration, in combination with a laser-controllable shock wave locally deforming the target surface. (C) 2010 Elsevier B.V. All rights reserved.
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| 6. |
- Batani, D., et al.
(författare)
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Effects of laser prepulse on proton generation
- 2010
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Ingår i: Radiation Effects and Defects in Solids. - : Informa UK Limited. - 1042-0150 .- 1029-4953. ; 165:6-10, s. 794-802
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Konferensbidrag (refereegranskat)abstract
- Prepulse is a major issue for laser generation of protons, often limiting the performances of laser sources. Here, we show the use of prepulse (1013W/cm2, ns duration) to actively manipulate the proton beam direction. Under oblique high-intensity irradiation (approximate to 1019W/cm2, ps duration) of the thin foil target, and for low prepulse intensities, the proton beam is directed away from the ounperturbedo target normal. Observations are discussed in terms of target normal sheath acceleration, in combination with a laser-controllable shock locally deforming the target surface.
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| 7. |
- Batani, D., et al.
(författare)
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Effects of laser prepulses on laser-induced proton generation
- 2010
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Low-intensity laser prepulses (<10(13) W cm(-2), nanosecond duration) are a major issue in experiments on laser-induced generation of protons, often limiting the performances of proton sources produced by high-intensity lasers (approximate to 10(19) W cm(-2), picosecond or femtosecond duration). Depending on the intensity regime, several effects may be associated with the prepulse, some of which are discussed in this paper: (i) destruction of thin foil targets by the shock generated by the laser prepulse; (ii) creation of preplasma on the target front side affecting laser absorption; (iii) deformation of the target rear side; and (iv) whole displacement of thin foil targets affecting the focusing condition. In particular, we show that under oblique high-intensity irradiation and for low prepulse intensities, the proton beam is directed away from the target normal. Deviation is towards the laser forward direction, with an angle that increases with the level and duration of the ASE pedestal. Also, for a given laser pulse, the beam deviation increases with proton energy. The observations are discussed in terms of target normal sheath acceleration, in combination with a laser-controllable shock wave locally deforming the target surface.
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| 8. |
- Björklund Svensson, Jonas, et al.
(författare)
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Double-bunches for two-color soft X-ray free-electron laser at the MAX IV Laboratory
- 2018
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Ingår i: Proceedings of FEL2017, Santa Fe, NM, USA. - 9783954501793 ; , s. 269-272
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The ability to generate two-color free-electron laser (FEL) radiation enables a wider range of user experiments than just single-color FEL radiation. There are different schemes for generating the two colors, the original being to use a single bunch and two sets of undulators with different K-parameters. An alternative scheme was recently shown, where two separate bunches in the same RF bucket are used for lasing at different wavelengths in a single set of undulators. We here investigate the feasibility of accelerating and compressing a double-bunch time structure generated in the photocathode electron gun for subsequent use in a soft X-ray FEL at the MAX IV Laboratory.
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| 9. |
- Björklund Svensson, Jonas, et al.
(författare)
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Driver-witness-bunches for plasma-wakefield acceleration at the MAX IV Linear Accelerator
- 2017
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Ingår i: IPAC 2017 - Proceedings of the 8th International Particle Accelerator Conference. - 9783954501823 ; , s. 1743-1746
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Beam-driven plasma-wakefield acceleration is an acceleration scheme promising accelerating fields of at least two to three orders of magnitude higher than in conventional radiofrequency accelerating structures. The scheme relies on using a charged particle bunch (driver) to drive a non-linear plasma wake, into which a second bunch (witness) can be injected at an appropriate distance behind the first, yielding a substantial energy gain of the witness bunch particles. This puts very special demands on the machine providing the particle beam. In this article, we use simulations to show that, if driver-witness-bunches can be generated in the photocathode electron gun, the MAX IV Linear Accelerator could be used for plasma-wakefield acceleration.
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| 10. |
- Brandin, Mathias, et al.
(författare)
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Status of the fel test facility at MAX-LAB
- 2007
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Ingår i: ; , s. 513-516
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Konferensbidrag (refereegranskat)abstract
- An FEL test facility is built on the existing MAX-lab linac system in collaboration between MAX-lab and BESSY. The goal is to study and analyse seeding, harmonic generation, beam compression and diagnostic techniques with the focus of gaining knowledge and experience for the MAX IV FEL and the BESSY FEL projects. The test facility will in the first stage be using the 400 MeV linac beam to generate the third harmonic at 88 nm from a 266 nm Ti:Sapphire seed laser. The optical klystron is installed and magnetic system, gun and seed laser systems are currently being finalised. Start-to-end simulations have been performed and operation modes for bunch compression defined. The linac and beam transport system is already in operation.
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