Collimation for the LHC high intensity beams

The unprecedented design intensities of the LHC require several important advances in beam collimation. With its more than 100 collimators, acting on various planes and beams, the LHC collimation system is the biggest and most performing such system ever designed and constructed. The solution for LHC collimation is explained, the technical components are introduced and the initial performance is presented. Residual beam leakage from the system is analysed. Measurements and simulations are presented which show that collimation efficiencies of better than 99.97 % have been measured with the 3.5 TeV proton beams of the LHC, in excellent agreement with expectations.peer-reviewe

CERN-MEDICIS: Operational indicators to support the production of new medical radionuclides by mass-separation

CERN-MEDICIS is an isotope mass separation facility dedicated to biomedical research located in a type A work sector, receiving on average 50% of the 1.4 GeV protons delivered by the Proton Synchrotron Booster (PSB). It was commissioned with Radioactive Ion Beams (RIB’s) in 2017. MEDICIS has operated for the past 5 years in batch mode, with targets irradiated in a station located at the HRS beam dump, and with external sources provided by MEDICIS cyclotrons and nuclear reactors partners, notably during the Long Shutdown (LS2). Additional features of the facility include the MELISSA laser ion source, radiochemistry on implanted radionuclides and an online gamma-ray spectroscopy implantation monitoring. In 2022, we introduced Key Performance Indicators (KPI’s) to monitor the operation of the facility for collected efficiencies, the optimisation of the radiological risks and evaluate impact of possible modifications of the station, paralleling for instance LHC’s integrated luminosity. Defined KPI’s cover aspects in the operation cycle, e.g. planning in CERN schedule, target irradiations, duration of the process, radiological risk mitigation, facility up-time, developments and maintenance. MEDICIS KPI’s can help distinguish which of the operation and infrastructure life cycle requires immediate intervention, developments or consolidation. Those are related to the irradiation stations and irradiation possibilities, the beamlines (parallel collections), target and ion sources (reliability), robot handling and infrastructure, or the separation process itself.CERN-MEDICIS is an isotope mass separation facility for biomedical R&D; located in a class A laboratory, receiving up to 50% of the 1.4GeV PSB protons. It was commissioned with radioactive ion beams in 2017. MEDICIS has operated for the past 5 years in batch mode, with targets irradiated in a dedicated beam dump station at HRS, and with external sources provided by cyclotrons and nuclear reactors MEDICIS partners, notably during Long Shutdown LS2 [1,2]. Recent additions to the CERN-MEDICIS facility are the MELISSA laser ion source, radiochemistry on implanted isotopes, and online gamma implantation monitoring.In 2022, we introduced key performance indicators (KPI’s) to monitor the facility for collected efficiencies, the optimization of the radiological risks and impact of modifications of the irradiation station, like the yearly integrated luminosity serves as one of the KPI's for LHC. Defined KPI’s cover different aspects in the operation cycle, such as planning in CERN schedule, target irradiations, process duration, radiological risk mitigation, facility downtime, developments and maintenance. MEDICIS KPI’s can help distinguish which of the elements in the operation and in the facility life-cycle thus requires immediate intervention, developments or consolidation.Those deal with the irradiation stations, beam-lines (parallel collections), target and ion sources (reliability), robot handling and infrastructure, or the separation process itself

First cleaning with LHC collimators

The LHC has two dedicated cleaning insertions: IR3 for momentum cleaning and IR7 for betatron cleaning. The collimation system has been specified and built with tight mechanical tolerances (e.g. jaw flatness ~ 40 μm ) and is designed to achieve a high accuracy and reproducibility of the jaw positions (~ 20 μm). The practically achievable cleaning efficiency of the present Phase-I system depends on the precision of the jaw centering around the beam, the accuracy of the gap size and the jaw parallelism against the beam. The reproducibility and stability of the collimation system is important to avoid the frequent repetition of beam based alignment which is currently a lengthy procedure. Within this paper we describe the method used for the beam based alignment of the LHC collimation system, its achieved accuracy and stability and its performance at 450GeV