SHADOWS (Search for Hidden And Dark Objects With the SPS):Letter of Intent

We propose a new proton beam-dump experiment, SHADOWS, to search for a large variety of feebly-interacting particles possibly produced in the interactions of a 400 GeV proton beam with a high-Z material dump. SHADOWS will use the 400 GeV primary proton beam extracted from the CERN SPS currently serving the NA62 experiment in the CERN North area. SHADOWS will take data off-axis concurrently to the HIKE experiment when the P42 beam line is operated in beam-dump mode to accumulate up to 5 · 10^19 protons on target in 4 years of operation. This document describes the main achievements with respect to the Expression of Interest and represents an intermediate step towards the Proposal

The Forward Physics Facility at the High-Luminosity LHC

High energy collisions at the High-Luminosity Large Hadron Collider (LHC) produce a large number of particles along the beam collision axis, outside of the acceptance of existing LHC experiments. The proposed Forward Physics Facility (FPF), to be located several hundred meters from the ATLAS interaction point and shielded by concrete and rock, will host a suite of experiments to probe standard model (SM) processes and search for physics beyond the standard model (BSM). In this report, we review the status of the civil engineering plans and the experiments to explore the diverse physics signals that can be uniquely probed in the forward region. FPF experiments will be sensitive to a broad range of BSM physics through searches for new particle scattering or decay signatures and deviations from SM expectations in high statistics analyses with TeV neutrinos in this low-background environment. High statistics neutrino detection will also provide valuable data for fundamental topics in perturbative and non-perturbative QCD and in weak interactions. Experiments at the FPF will enable synergies between forward particle production at the LHC and astroparticle physics to be exploited. We report here on these physics topics, on infrastructure, detector, and simulation studies, and on future directions to realize the FPF's physics potential

Photonic crystal fibre laser for electron beam emittance measurement

We present the successful development of a new fibre laser system for a laser-wire electron beam emittance diagnostic, suitable for intra-train scanning in an ILC-specification environment. The system is based on the amplification of a commercial Ytterbium (Yb) fibre laser with a repetition rate of 6.49MHz in rod type Yb doped photonic crystal fibre (PCF). We demonstrate world leading laser performance, with amplification of pulses from 1.5μJ to 268μJ and a beam quality factor M2 < 1.1, in 1ms bursts at 2Hz. Copyright © 2011 by IPAC'11/EPS-AG

High power fiber laser system for a high repetition rate laserwire

We present the development of a high power fiber laser system to investigate its suitability for use in a transverse electron beam profile monitor, i.e., a laserwire. A system capable of producing individual pulses up to 165.8±0.4μJ at 1036 nm with a full width at half maximum of 1.92±0.12ps at 6.49 MHz is demonstrated using a master oscillator power amplifier design with a final amplification stage in a rod-type photonic crystal fiber. The pulses are produced in trains of 1 ms in a novel burst mode amplification scheme to match the bunch pattern of the charged particles in an accelerator. This method allows pulse energies up to an order of magnitude greater than the steady-state value of 17.0±0.6μJ to be achieved at the beginning of the burst with a demonstrated peak power of 25.8±1.7MW after compression. The system is also shown to demonstrate excellent spatial quality with an M2=1.26±0.01 in both dimensions, which would allow nearly diffraction limited focusing to be achieved. © 2014 Published by the American Physical Society

A high power fibre laser for electron beam emittance measurements

We present the latest results on the development of a high power fibre laser system for a laser-wire measuring electron beam emittance in an ILC-specification environment. The laser consists of a commercial Ytterbium (Yb) doped fibre laser system producing 1μJ pulses at 6.49MHz, which can be locked to an external frequency reference. This output has been amplified in a single 70cm rod type photonic crystal fibre (PCF), producing ∼ 100μJ pulses in a burst mode at 2Hz (limited by diagnostics)

Multiple Pulse Resonantly Enhanced Laser Plasma Wakefield Acceleration

We present an outline of experiments being conducted at Oxford University on multiple-pulse, resonantly-enhanced laser plasma wakefield acceleration. This method of laser plasma acceleration uses trains of optimally spaced low energy short pulses to drive plasma oscillations and may enable laser plasma accelerators to be driven by compact and efficient fibre laser sources operating at high repetition rates. © 2012 American Institute of Physics