[en] The possibility is presented of using electro-optics techniques to increase laser-wire scanning rates for intra-train scanning at the international linear collider (ILC). The requirements include the preservation of the laser beam mode quality and the ability to work with laser beam powers of order 10 MW. The first ideas of a possible device configuration are presented together with a survey of EO materials and first experimental results using linear prisms. (author)

[en] At the HL-LHC, proton bunches will be rotated by crab cavities close to the interaction regions to maximize the luminosity. A method to rapidly monitor the transverse position of particles within each 1 ns bunch is required. A novel, compact beam diagnostic to measure the bunch rotation is under development, based on electro-optic crystals, which have sufficient time resolution (< 50ps) to monitor intra-bunch perturbations. The electro-optic beam position monitor uses two pairs of crystals, mounted on opposite sides of the beam pipe, whose birefringence is modified by the electric field of the passing charged particle beam. The change of birefringence depends on the electric field which itself depends on the beam position, and is measured using polarized laser beams. The electro-optic response of the crystal to the passing bunch has been simulated for HL-LHC bunch scenarios. An electro-optical test stand including a high voltage modulator has been developed to characterize LiTaO₃ and LiNiO₃ crystals. Tests to validate the different optical configurations will be reviewed. The opto-mechanical design of an electro-optic prototype that will be installed in the CERN SPS will be presented. (author)

[en] A laser-based profile monitor has been designed for commissioning of CERN’s LINAC4 accelerator at 50 MeV and 100 MeV, as part of the development of a non-destructive profile and emittance monitor foreseen for the final 160 MeV beam. The system is based on a low power laser which is scanned through the H ⁻ beam. Electrons, which are photo detached from the ions by the laser, are deflected by a steerer magnet and measured by a diamond detector. The custom designed diamond detector is tailored to minimize the disturbance due to the electromagnetic field of the passing main beam. The laser source will be installed in the LINAC4 Klystron gallery located 75 m away from the profile station and an optical fiber will transport the laser to the tunnel. The laser propagation for different pulse length and peak power values was characterized with laboratory tests with such a long fiber. In this paper we describe the overall design, focusing on key elements such as the fiber-based laser transport and the electron detection with the diamond detector. (author)

[en] Advanced laser systems will be essential for a range of diagnostics devices and polarimetry at the ILC. High average power, high beam quality, excellent stability and reliability will be crucial in order to deliver the information required to attain the necessary ILC luminosity as well as for efficient polarimetry. The key parameters are listed together with the R and D required to achieve the necessary laser system performance

[en] A first prototype of optical scanner based on a CCD camera and the use of Fricke-agarose-XO has allowed us to reconstruct 3D dose maps, monitoring doses in the range 0.5-3 Gy. Measurements performed with laboratory tests and with clinical beams would indicate that the uncertainty involved in dose mapping are compatible with requirements of a 3D dosimetry for the verifications of treatment plans.

[en] A new laser-wire (LW) system has been installed at the ATF extraction line at KEK, Tsukuba. The system aims at a micron-scale laser spot size and employs a mode-locked laser system. The purpose-built interaction chamber, light delivery optics, and lens systems are described, and the first results are presented

[en] An instrument to non-destructively measure the transverse profile of an H⁻ beam has been developed and tested at CERN’s new LINAC4. The vertical profile of the H⁻ beam has been measured, at beam commissioning energies of 50, 80 and 107 MeV. The instrument consists of a laser-source which is coupled to an optical fibre, delivering laser pulses with hundreds Watts of peak power to the accelerator tunnel, where the laser beam is focused horizontally onto the H⁻ beam. Due to photo-detachment, electrons are liberated from the ions and can be deflected by a weak dipole field onto a diamond detector. The beam profile is obtained by scanning the laser beam vertically across the H⁻ beam and recording for each position the number of arriving electrons. The design, implementation and characterisation of the novel instrument shall be described and the measured beam profiles compared to profiles obtained with SEM-grids and wirescanners.

[en] Optical methods for non-invasive beam diagnostics of high current H⁻ ion accelerators have been developed in recent years. Such laserwires typically measure a 1D beam profile and/or 2D transverse emittance from the products of photo-detached ions as a laser beam is scanned across the H⁻ beam. For laser pulse durations (∼80 ns) longer than the RF period (∼3ns), the detector integrates many complete bunches, enabling only transverse beam monitoring. This paper presents a new technique to capture a series of time resolved transverse emittance measurements along the bunch train. A fast (∼10 ps) pulsed laser photo-detaches ions within each bunch and is synchronised to sample consecutive bunches at certain longitudinal positions along each bunch. A fast detector records the spatial distribution and time-of-flight of the neutralised H⁰, thus both the transverse and longitudinal emittance are reconstructed. We present simulations of a time varying pulsed laser field interacting within an H⁻ bunch, and estimate the yield, spatial and time distributions of H⁰ arriving at the detector. We summarise the design of a recently funded longitudinal laserwire being installed in FETS at RAL, UK. (paper)

[en] Non-linear photo-excited processes using the photorefractive effect are revisited with emphasis on spatial soliton generation in special laser beam propagation conditions. The soliton beams can create reversible or irreversible single-mode waveguides in the propagating materials. The important features are the 3D orientation and graded index profile matched to the laser fundamental mode. Bright spatial solitons are theoretically demonstrated and experimentally observed for the propagation of c.w. and pulsed femtosecond laser beams in photorefractive materials such as Bi₁₂ SiO₂₀ (BSO) and lithium niobate crystals. Applications in high coupling efficiency, adaptive optical interconnections and photonic crystal production are possible

[en] A two-dimensional laser-wire scanner capable of measuring the transverse charge profiles of an electron (or positron) bunch has been constructed at the PETRA accelerator in DESY. The development of the system is explained in this paper, along with descriptions of its photon detector and laser system. Results of transverse profile scans are presented for both horizontal and vertical directions. The measurement error is 1.3% from a multi-scan measurement in the vertical direction, where single scans can be performed in less than 50 s