Technical Proposal for FASER: ForwArd Search ExpeRiment at the LHC

FASER is a proposed small and inexpensive experiment designed to search for light, weakly-interacting particles during Run 3 of the LHC from 2021-23. Such particles may be produced in large numbers along the beam collision axis, travel for hundreds of meters without interacting, and then decay to standard model particles. To search for such events, FASER will be located 480 m downstream of the ATLAS IP in the unused service tunnel TI12 and be sensitive to particles that decay in a cylindrical volume with radius R=10 cm and length L=1.5 m. FASER will complement the LHC's existing physics program, extending its discovery potential to a host of new, light particles, with potentially far-reaching implications for particle physics and cosmology. This document describes the technical details of the FASER detector components: the magnets, the tracker, the scintillator system, and the calorimeter, as well as the trigger and readout system. The preparatory work that is needed to install and operate the detector, including civil engineering, transport, and integration with various services is also presented. The information presented includes preliminary cost estimates for the detector components and the infrastructure work, as well as a timeline for the design, construction, and installation of the experiment.Comment: 82 pages, 62 figures; submitted to the CERN LHCC on 7 November 201

First neutrino interaction candidates at the LHC

FASER$\nu$ at the CERN Large Hadron Collider (LHC) is designed to directly detect collider neutrinos for the first time and study their cross sections at TeV energies, where no such measurements currently exist. In 2018, a pilot detector employing emulsion films was installed in the far-forward region of ATLAS, 480 m from the interaction point, and collected 12.2 fb$^{-1}$ of proton-proton collision data at a center-of-mass energy of 13 TeV. We describe the analysis of this pilot run data and the observation of the first neutrino interaction candidates at the LHC. This milestone paves the way for high-energy neutrino measurements at current and future colliders.Comment: Auxiliary materials are available at https://faser.web.cern.ch/fasernu-first-neutrino-interaction-candidate

The n_TOF-EAR2 facility at CERN: neutron flux determination and 33^{33}S(n,α\alpha)30^{30}Si cross section measurement; implications in BNCT.

The main aim of this project is the first measurement of the $^{33}$S(n,$\alpha$)$^{30}$Si cross section at the neutron time-of-flight n_TOF facility at CERN from few meV to10 keV, covering the existing lack of experimental data. The measurement was performed in the summer of 2015 in the new beam line of the n_TOF facility, n_TOF-EAR2. In order to complete the measurement, the characterization of the neutron beam becomes essential to determine the cross section. Therefore, an important part of the present work is dedicated to the description of the n_TOF-EAR2 features and, in particular, to the evaluation of the neutron flux of the facility by means of combining different cross section measurements considered standards. $^{33}$S is a stable isotope of sulphur of interest in Neutron Capture Therapy for treating superficial tumours. The data obtained was included in Monte Carlo simulations of the kerma rate for studying the effect of $^{33}$S in the therapy

On the resolution function of the n_TOF facility: a comprehensive study and user guide

The purpose of this report is to provide the necessary information and tools for the n_TOF Collaboration on how to correctly account for the neutron resolution function in the experimental areas (EAR1 and EAR2) for different n_TOF operation periods. The n_TOF target as well as the cooling/moderation system was designed to optimize the performances of the neutron beam for EAR1. Additionally, EAR1 is located underground 200 m away, in nearly the same direction as the incoming proton beam, from the spallation target. On the contrary, EAR2 was an extension of the existing facility. It is located above the ground at 20 m from the spallation target in the perpendicular direction with respect to the incoming proton beam. Even though the energy resolution is worse due to the shorter flightpath, the main issue with the resolution function comes from the geometry of the cooling/moderation system and the shape of the spallation target. Experimental data acquired in any of the experimental areas has embedded the effect of the resolution function. Therefore, when treating these data there are two options. Either deconvolute them from the resolution function or convolve the reference data, for instance evaluated cross sections, with the resolution function to be able to compare both sets of data in the same conditions. Usually, the second method is adopted for simplicity. In both cases the explicit distribution of the resolution function should be available. Even more, to perform the resonance analysis with SAMMY or REFIT this information must be known. The question here is: how to obtain the resolution function

Update on the FPF Facility technical studies

The Forward Physics Facility (FPF) is a proposed new facility to house several new experiments at the CERN High Luminosity LHC (HL-LHC). The FPF is located such that the experiments can be aligned with the collision axis line of sight (LOS), a location which allows many interesting physics measurements and searches for new physics to be carried out. The status of technical studies related to the FPF, as well as the physics potential were documented in Ref. [1] which was released in March 2022. This note documents updates to the FPF technical studies completed since that time

Electronics Irradiation With Neutrons at the NEAR Station of the n_TOF Spallation Source at CERN

We study the neutron field at the NEAR station of the neutron time-of-flight (n_TOF) facility at CERN, through Monte Carlo simulations, well-characterized static random access memories (SRAMs), and radio-photoluminescence (RPL) dosimeters, with the aim of providing neutrons for electronics irradiation. Particle fluxes and typical quantities relevant for electronics testing were simulated for several test positions at NEAR and compared to those at the CERN high-energy accelerator mixed-field facility (CHARM), highlighting similitudes and differences. The SRAM detectors, based on single-event upset (SEU) and single-event latch-up (SEL) counts, each one with a different energy response, and RPL dosimeters were tested in a reference position, and the results were benchmarked to FLUKA simulations. Finally, the neutron spectra at NEAR are compared to those of the most well-known spallation sources and typical environments of interest, for accelerator and atmospheric applications, showing the potential of the facility for electronics irradiation

LHC Triplet Task Force Report

The excellent performance of the Large Hadron Collider (LHC) and the extension of Run 3 by one year have led to a significant increase of the expected integrated luminosity by the end of its operation and before the start of the High Luminosity LHC (HL-LHC), exceeding the design LHC integrated luminosity of 300 fb−1 for which the final focus region has been designed. The radiation dose accumulated by the components close to the Interaction Points (IPs) and resulting from the collision debris might approach or exceed the radiation limits that have guided the selection of the materials in the design of these components. A task force has been set-up to analyse the potential impact on machine performance and availability and identify mitigation measures. The results of the studies conducted by the Task Force are summarized in this report

Technical Proposal for FASER: ForwArd Search ExpeRiment at the LHC

FASER is a proposed small and inexpensive experiment designed to search for light, weakly-interacting particles during Run 3 of the LHC from 2021-23. Such particles may be produced in large numbers along the beam collision axis, travel for hundreds of meters without interacting, and then decay to standard model particles. To search for such events, FASER will be located 480 m downstream of the ATLAS IP in the unused service tunnel TI12 and be sensitive to particles that decay in a cylindrical volume with radius R=10 cm and length L=1.5 m. FASER will complement the LHC's existing physics program, extending its discovery potential to a host of new, light particles, with potentially far-reaching implications for particle physics and cosmology. This document describes the technical details of the FASER detector components: the magnets, the tracker, the scintillator system, and the calorimeter, as well as the trigger and readout system. The preparatory work that is needed to install and operate the detector, including civil engineering, transport, and integration with various services is also presented. The information presented includes preliminary cost estimates for the detector components and the infrastructure work, as well as a timeline for the design, construction, and installation of the experiment

Technical Proposal: FASERnu

FASERnu is a proposed small and inexpensive emulsion detector designed to detect collider neutrinos for the first time and study their properties. FASERnu will be located directly in front of FASER, 480 m from the ATLAS interaction point along the beam collision axis in the unused service tunnel TI12. From 2021-23 during Run 3 of the 14 TeV LHC, roughly 1,300 $\nu_e$, 20,000 $\nu_{\mu}$, and 20 $\nu_{\tau}$ will interact in FASERnu with TeV-scale energies. With the ability to observe these interactions, reconstruct their energies, and distinguish flavors, FASERnu will probe the production, propagation, and interactions of neutrinos at the highest man-made energies ever recorded. The FASERnu detector will be composed of 1000 emulsion layers interleaved with tungsten plates. The total volume of the emulsion and tungsten is $25cm \times 25cm \times 1.35m$, and the tungsten target mass is 1.2 tonnes. From 2021-23, 7 sets of emulsion layers will be installed, with replacement roughly every $20-50~fb^{-1}$ in planned Technical Stops. In this document, we summarize FASERnu's physics goals and discuss the estimates of neutrino flux and interaction rates. We then describe the FASERnu detector in detail, including plans for assembly, transport, installation, and emulsion replacement, and procedures for emulsion readout and analyzing the data. We close with cost estimates for the detector components and infrastructure work and a timeline for the experiment.FASERnu is a proposed small and inexpensive emulsion detector designed to detect collider neutrinos for the first time and study their properties. FASERnu will be located directly in front of FASER, 480 m from the ATLAS interaction point along the beam collision axis in the unused service tunnel TI12. From 2021-23 during Run 3 of the 14 TeV LHC, roughly 1,300 electron neutrinos, 20,000 muon neutrinos, and 20 tau neutrinos will interact in FASERnu with TeV-scale energies. With the ability to observe these interactions, reconstruct their energies, and distinguish flavors, FASERnu will probe the production, propagation, and interactions of neutrinos at the highest human-made energies ever recorded. The FASERnu detector will be composed of 1000 emulsion layers interleaved with tungsten plates. The total volume of the emulsion and tungsten is 25cm x 25cm x 1.35m, and the tungsten target mass is 1.2 tonnes. From 2021-23, 7 sets of emulsion layers will be installed, with replacement roughly every 20-50 1/fb in planned Technical Stops. In this document, we summarize FASERnu's physics goals and discuss the estimates of neutrino flux and interaction rates. We then describe the FASERnu detector in detail, including plans for assembly, transport, installation, and emulsion replacement, and procedures for emulsion readout and analyzing the data. We close with cost estimates for the detector components and infrastructure work and a timeline for the experiment