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Alternate wetting and drying (AWD) technique has been developed and evaluated on rice (Oryza sativa) systems in several countries worldwide for increasing water use efficiency and reducing negative effects of permanent flooding, like the increase in methane emissions and arsenic availability in soil. In this study, a paddy field experiment was carried out for two years to evaluate the application in Northern Italy rice area of a moderate AWD, i.e. only implemented during the vegetative phase of the crop and ponded water maintained thereafter, compared with Continuous Flooding (CF) system. The adaptability of 12 European commercial rice cultivars to AWD was investigated in terms of crop phenology, morphological traits, root production, nitrogen (N) uptake, yield, milled rice yield and microelement concentration in grains. Results showed substantial (40.7 %) water saving probably favoured by the presence of a shallow water table. In these pedoclimatic conditions, very limited effects of a mild AWD on crop status and final productivity were recorded and the commercial cultivars did not display significant different adaptabilities to the water stress. Moreover, AWD decreased arsenic (As) concentration in grain but increased grain Cadmium (Cd) being the degree of such a response dependent upon the variety, suggesting that the genotype plays an important role in this aspect of adaptation to AWD. info:eu-repo/semantics/acceptedVersion

International audience; Saclay CEA/IRFU is working for the delivery of five Non-Invasive Profile Monitors in the frame of the in-kind contribution agreement signed with the European Spallation Source. Neutrons will be produced by spallation reactions of 2 GeV proton beam impinging on a Tungsten target. To accelerate protons a powerful linear accelerator of 5MW is under construction. Diagnostic devices are mandatory tools for the tuning and protection of the machine. The non-invasive profile monitors provide a measurement of the beam profile in transverse directions to the beam propagation. This project raises several physical and technical challenges including low signal detection of ions or electrons, profile distortions induced by the beam Space Charge effect and non-uniformities of electric field. Simulation and model of the critical aspects of the detector have been performed in order to prove the performance and the feasibility of the detector. A series of prototypes has been built with different readout types, and tested in real conditions at the 3MeV proton accelerator IPHI. All of them show some advantages and drawbacks revealed by the tests in real beam conditions. In this paper we present the results of the tests for the various configuration readout systems to agree with the model and simulation of the detector. In concluding remarks, we will discuss the performance of the prototypes and point out the camerabased one to be the more suitable for the final design.Key words: Beam diagnostic / Linear proton accelerators / MCP / Strip detector / Particle beam measurements

In a Storage Ring Free Electron Laser (SRFEL) there is a strong interdependence between the laser beam and the electron beam from which the laser is generated. The Super ACO storage ring has a second Radio Frequency (RF) cavity at the 5th harmonic of the main RF cavity. It is used to shorten the bunch length, thereby enhancing the laser gain. Employing this RF harmonic cavity instabilities are observed with a strong effect on both the laser radiation properties and the electron beam behaviour. In this paper, we first present beam characteristics of Super-ACO as influenced by the harmonic cavity, and the instabilities of the beam due to this RF cavity. Then we discuss the FEL properties in presence of the harmonic RF cavity. In general the harmonic cavity functions as intended, and it is observed that the laser suppresses the instabilities caused by the harmonic cavity in the absence of the FEL.PACS: 41.60.Cr Free-electron lasers - 05.45.-a Nonlinear dynamics and nonlinear dynamical systems - 29.20.Dh Storage rings - 41.75.Fr Electron and positron beams

The interaction between laser pulse and electron beam of a storage ring free electron laser (SRFEL) can be described in the longitudinal phase space as a function of the longitudinal detuning, which we define as the delay per pass between the laser pulse and the electron bunch. SRFEL dynamics versus detuning is studied by comparison of measurements performed at Super ACO with a numerical code. Experimental phenomena regarding detuning have been properly predicted by simulations. Quantitative agreement for pulse duration, pulse repetition frequency, laser power, etc. has been found.

Single shot transverse emittance measurement is essential to assess the beam quality and performance of new generation light sources such as linac based X-ray Free Electron Lasers (FELs) or laser plasma wakefield accelerators (LPWA). To this end, we have developed a single shot transverse emittance measurement using at least 3 screens inserted in the beam at the same time, measuring the beam size at different positions in a drift space in one single shot. In this paper, we firstly present the theoretical aspects to perform the measurement. We secondly show experimental results obtained at Diamond for a 3 GeV electron beam in the transfer line from the Booster to the Storage Ring, using this thin OTR screens method. Finally, we discuss the results showing the strength of the measurement in comparison with more standard and established emittance measurement, like the quadrupole scan method. © 2011 IOP Publishing Ltd and SISSA.

In this paper we present the experience at Diamond Light Source in the design, implementation, and operation of low momentum compaction factor lattices for the generation of short x-ray pulses and coherent THz radiation. The effects of higher-order terms in the expansion of the momentum compaction factor on beam dynamics are reviewed from a theoretical point of view, and the details of both high- and low-emittance solutions at Diamond are discussed. Measurements taken to characterize the lattices under a variety of machine conditions are presented, along with the practical limitations that exist as the momentum compaction factor is made to approach zero. © 2011 American Physical Society.

Third generation synchrotron light sources are characterized by a low emittance and a low emittance coupling. Some light sources are already operating with extremely low coupling close to 0.1%. Measurement of the transverse beam size is generally used to measure the emittance and the coupling. To this end, several systems are currently used and an x-ray pinhole camera is one of them. In this paper we derive the point spread function of the x-ray pinhole camera both analytically and numerically using the Fresnel diffraction integral and taking into account the broadband spectrum of the bending magnet source, and we show that an optimized design allows the measurement of extremely small vertical beam sizes below $5\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$. The point spread function of several scintillator screens is also measured, and it shows that the contribution of the diffraction and the screen point spread functions have to be taken into account for an accurate measurement of a low coupling. Finally, we show measurements of the vertical beam sizes as small as $6\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ for our nonoptimized setup.

060701-1 Collective effects, such as the microwave instability, influence the longitudinal dynamics of an electron beam in a storage ring. In a storage ring free electron laser (FEL) they can compete with the induced beam heating and thus be treated as a further concomitant perturbing source of the beam dynamics. Bunch length and energy spread measurements, carried out at the Super-ACO storage ring, can be correctly interpreted according to a broad-band impedance model. Quantitative estimations of the relative role that is played by the microwave instability and the laser heating in shaping the beam longitudinal dynamics have been obtained by the analysis of the equilibrium laser power. It has been performed in terms of either a theoretical limit, implemented with the measured beam longitudinal characteristics, or the numerical results obtained by a macroparticle tracking code, which includes the laser pulse propagation. Such an analysis, carried out for different operating points of the Super-ACO storage ring FEL, indicates that the laser heating counteracts the microwave instability.

Magnetic susceptibility and X- and Q-band EPR studies are reported for the Fe 2+ spin transition compound (Fe( PM-PEA ) 2 (NCS) 2 ) in powder form. An exceptionally large thermal hysteresis loop, about 60 K, has been found by both techniques. The EPR studies have been carried out on compound doped with Mn 2+ (0.1‰ of Mn/Fe). An original EPR spectra simulation program has been elaborated in order to yield data on the structural modifications accompanying the spin transition. The fine structure parameters obtained by simulations in the high-spin state of Fe 2+ , D =460, E =25, and in the low-spin state of this ion, D =235, E =20 (in 10 −4 cm −1 ) confirm that the spin transition is accompanied by a crystalline phase transformation. The Mn 2+ EPR spectra in the spin transition region can be convincingly fitted by linear combinations of the spectra observed in the high-spin and low-spin states of Fe 2+ , indicating that the spin transition occurs in domains of like-spin ions.

We present experimental measurements of the coherence of an undulator synchrotron radiation source near to the diffraction limit condition. These measurements have been done following two objectives. The first one is to verify a fundamental point of the theory of synchrotron radiation. To our knowledge, since it has been re-written by Geloni et al. [1] , no experimental verification to validate the theory has been performed. Our measurement proves the theory to be valid for the case of a near diffraction limited undulator source. The other objective is to measure the coherence of the synchrotron radiation on the I05 beamline of Diamond, in front of the last focusing element of the beamline. This knowledge can be used to predict the focusing performance of the beamline by means of Fourier Optics.