Terahertz multispectral imaging by thermo-conversion using MIM antenna

International audienceConversion of terahertz radiation into thermal radiation is a low-cost approach for terahertz detection by standard infrared camera. In this work, THz→IR thermo-conversion is performed by the combination of a THz absorber made of MIM antenna and an emissive layer made of carbon nanotubes. Structural and optical characterizations of the membrane are done, and multispectral imaging in the terahertz range is demonstrated

Terahertz multispectral imaging by thermo-conversion using MIM antenna

International audienceConversion of terahertz radiation into thermal radiation is a low-cost approach for terahertz detection by standard infrared camera. In this work, THz→IR thermo-conversion is performed by the combination of a THz absorber made of MIM antenna and an emissive layer made of carbon nanotubes. Structural and optical characterizations of the membrane are done, and multispectral imaging in the terahertz range is demonstrated

First Step to Manage Migration to Siemens S7-15XX PLCs using TANGO Framework

International audienceOver the past years, SOLEIL* uses SIEMENS PLCs** as a standard for signal monitoring and security. SOLEIL is today thinking about a major upgrade of the facilities, and has to adapt its organization to face efficient operation and R&D. In this context, automation experts are now merged in a single group. In a middle term, migration from the existing 3XX series PLCs to the new 15XX series will be necessary. As the new 15XX series PLCs do not support Fetch/Write protocol anymore, a first step is the upgrade of TANGO*** PLCServer. This software device ensures data exchange with supervisory applications using TANGO infrastructure. It opens multiple TCP/IP connections to the PLC hardware, manages asynchronous communication to read/write PLC Datablocks and acts as a server for other clients. The upgrade of PLCServer is based on Snap7**** open source Ethernet communication suite for interfacing with Siemens PLCs using the S7 native protocol. This paper details the evolutions, performances and limitations of this new version of the PLCServer

Construction and Optimization of Cryogenic Undulators at SOLEIL

International audienceWith permanent magnets undulator operation at cryogenic temperature, the magnetic field and the coercivity can be enhanced, enabling shorter periods with high magnetic fields. The first full scale (2 m long, 18 mm period) hybrid cryogenic undulator [1] using PrFeB [2] magnets operating at 77 K was installed at SOLEIL in 2011. Photon spectra measurements, in good agreement with the ex-pectations from magnetic measurements, were used for precise alignment and taper optimization. The second and third 18 mm PrFeB cryogenic undulators, modified to a half-pole/magnet/half-pole structure, were optimized without any magnet or pole shimming after assembly but mechanical sortings and some geometrical corrections had been done before assembly. A systematic error on individual magnets on the third U18 was also compensated. In-situ measurement benches, including a Hall probe and a stretched wire to optimize the undulator field at room and cryogenic temperature are presented. An upgrade of these in-situ benches will be detailed with the fabrication of a 15 mm 3 m long PrFeB cryogenic undulator at SOLEIL

Electron Transport on COXINEL Beam Line

International audienceCOXINEL experiment aims at demonstrating free electron laser (FEL) amplification with a laser plasma accelerator (LPA). For COXINEL, a dedicated 8 m transport line has been designed and prepared at SOLEIL. We present here LPA beam transport results around 180 MeV through this line. Different electron beam optics were applied

Study of the Electron Transport in the COXINEL FEL Beamline Using a Laser-Plasma Accelerated Electron Beam

International audienceThe ERC Advanced Grant COXINEL aims at demonstrating free electron laser (FEL) at 200 nm, based on a laser-plasma accelerator (LPA). To achieve the FEL amplification a transport line was designed to manipulate the beam properties. The 10 m long COXINEL line comprises a first triplet of permanent-magnet variable-strength quadrupoles (QUAPEVA), which handles the large divergence of LPA electrons, a magnetic chicane, which reduces the slice energy spread, and finally a set of electromagnetic quadrupoles, which provides a chromatic focusing in a 2-m undulator. Electrons were successfully transported through the line from LPA with ionization-assisted self-injection (broad energy spectra up to~250 MeV, few-milliradian divergence)

Mechanical Engineering Solutions for COXINEL Project

International audienceCOXINEL (COherent Xray source INferred from Electrons accelerated by Laser) is a European Research Council (ERC) advance grant aims at demonstrating Free Electron Laser amplification at 200 nm with 180 MeV electrons generated by laser plasma acceleration. A special electron beam transfer line with adequate diagnostics has been designed for this project. Strong-focusing variable-field permanent magnet quadrupoles, energy de-mixing chicane and a set of conventional quadrupoles condition the electron beam before its entrance to an In-Vacuum U20 undulator. This presentation describes some of the features incorporated into the design of the magnets, girders, vacuum vessels and diagnostic equipment for this experimental machine. Progress on the equipment preparation and installation is presented as well

Transportation and Manipulation of a Laser Plasma Acceleration Beam

International audienceThe ERC Advanced Grant COXINEL aims at demonstrating free electron laser amplification, at a resonant wavelength of 200 nm, based on a laser plasma acceleration source. To achieve the amplification, a 10 m long dedicated transport line was designed to manipulate the beam qualities. It starts with a triplet of permanent magnet with tunable gradient quadrupoles (QUAPEVA) that handles the highly divergent electron beam, a demixing chicane with a slit to reduce the energy spread per slice, and a set of electromagnetic quadrupoles to provide a chromatic focusing in a 2 m long cryogenic undulator. Electrons of energy 176 MeV were successfully transported throughout the line, where the beam positioning and dispersion were controlled efficiently thanks to a specific beam based alignment method, as well as the energy range by varying the slit width. Observations of undulator radiation for different undulator gaps are reported

Progress Towards Laser Plasma Electron Based Free Electron Laser on COXINEL

International audienceLaser plasma acceleration (LPA) with up to several GeV beam in very short distance appears very promising. The Free Electron Laser (FEL), though very challenging, can be viewed as a qualifying application of these new emerging LPAs. The energy spread and divergence, larger than from conventional accelerators used for FEL, have to be manipulated to fulfil the FEL requirements. On the test experiment COXINEL (ERC340015), the beam is controlled in a manipulation [1,2] line, using permanent magnet quadrupoles of variable strength [3] for emittance handing and a decompression chicane equipped with a slit for the energy selection, enabling FEL amplification for baseline reference parameters [2]. The electron position and dispersion are independently adjusted [4]. The measured spontaneous emission radiated by a 2 m long 18 mm period cryo-ready undulator exhibits the typical undulator spatio-spectral pattern, in agreement with the modelling of the electron beam travelling along the line and of the afferent photon generation. The wavelength is easily tuned with undulator gap variation. A wavelength stability of 2.6% is achieved. The undulator linewidth can be controlled

Control of Laser Plasma Accelerated Electrons: A Route for Compact Free Electron Lasers

International audienceThe recent spectacular development of laser plasma ac- celerators that now can deliver GeV electron beams in an extremelyshortdistancemakesthemverypromising. Ap- plications for light sources based on undulator radiation and free electron laser appear as an intermediate step to move from an acceleration concept to an accelerator qual- ification. However, the presently achieved divergence and energy spread require some electron beam manipulations. The COXINEL test line was designed for enabling Free Elec- tron Laser operation with baseline reference parameters. It comprises variable permanent magnet quadrupoles for di- vergence handling, a magnetic chicane for electron energy sorting, a second set of quadrupole for chromatic focusing and an undulator for synchrotron radiation emission and/or free electron laser gain medium. The transport along the line is controlled [1]. The synchrotron radiation emitted by the undulator radiation is studied under different conditions of detection (CCD camera, spectrometer), electron beam manipulation and undulator parameters. These observations pave the way towards Laser Plasma Acceleration based Free Electron Laser