Update on radiation estimates for the CLIC Main and Drive beams Sophie Mallows, Thomas Otto CLIC OMPWG

Contents CLIC OMPWG Part 1. Simulations of Beam Loss Limits w.r.t, damage to QP Magnets (New results for losses at 1.5 TeV) Part 2. Work on new simulations for Ambient Dose Equivalent Rates, Electronics Damage Some examples of preliminary results for losses in the Main Beam at 9 GeV

Beam Loss Limits - QP Damage - Loss Considerations CLIC OMPWG  Beam dynamics: (est. Daniel Schulte) Fractional loss 1 E-3 over main beam (2000 Quadrupoles) Fractional loss 1 E-3 in each drive beam section (800 QP)  Radiation damage to QP magnets Less than 1 MGy per year will conservatively assure survival of magnet insulation over lifetime of accelerator Use FLUKA to simulate losses and calculate absorbed doses in coils

CLIC OMPWG BPMs 50%Fe, 50%Cu at half density (awaiting new design) Beam Loss Limits - Damage to QP - FLUKA Geometry 1 Drive Beam Cross Section Detailed representation of QP, (rotated 45 deg for easier application of fine scoring mesh across coil regions)

CLIC OMPWG BPMs 50%Fe, 50%Cu at half density (same as DB BPM?) Cu Cu (half density) AS cross section Beam Loss Limits – Damage to QP - FLUKA Geometry 2 Main Beam Cross Sections – 9 GeV

CLIC OMPWG Main Beam Cross Sections – 1500 GeV Beam Loss Limits – Damage to QP - FLUKA Geometry 3

CLIC OMPWG 2.4 GeV Lost before QP 1. Find maximum absorbed dose in magnetic coil region per lost electron 2. Calculate no. of lost electrons required to produce 1 MGy 3.This number is presented as a fraction of the beam, assuming: Continuous Running for 180 days of the year at 1.16E12 per bunch, 50 hz - main beam 1.54E14 per bunch, 50 hz – drive beam Beam Loss Limits – Damage to Coil -Example Result

Loss pointFractional Beam Loss per QP - Beam Dynamics Fractional Beam Loss per QP – for 1 MGy/yr in coils in QP1.25 E-61.6 E-6 before QP1.25 E-62.1 E-6 in PET1.25 E CLIC OMPWG in QP1.25 E-61.9 E-5 before QP1.25 E-62.0 E-5 in PET1.25 E-64.8 E GeV 0.24 GeV Beam Loss Limits - Damage to QP - Results: Permitted Fractional Losses DB

Loss point Fractional Beam Loss per QP - Beam Dynamics Fractional Beam Loss per QP – for 1 MGy/yr in coils in QP1.25 E-61.9 E-5 before QP1.25 E-62.0 E-5 In AS1.25 E-64.8 E CLIC OMPWG 9 GeV Beam Loss Limits - Results: Permitted Fractional Losses MB

Loss points Fractional Beam Loss per QP - Beam Dynamics Fractional Beam Loss per QP – for 1 MGy/yr in coils in QP5 E-71.0 E-7 before QP5 E-71.0 E-7 in AS centre5 E-72.4 E-7 Continuous in AS (1m) 5 E-74.3 E CLIC OMPWG New Results Beam Loss Limits - Damage to QP - Results: Permitted Fractional Losses MB 1.5 TeV

CLIC OMPWG Cumulative Effects Lattice Displacement (non ionising energy losses) The Total Ionizing Dose (TID) Single Event Effects (SEEs) Damage Mechanism Quantified Same Bulk damages as 1 MeV neutrons 1 MeV-neutron equivalent fluence Absorbed dose in Gy Probabilistic- increases with increasing exposure to the radiation fluence of particles with E > 20 MeV, ‘20 MeV- hadron fluence’ Simulations for Electronics Damage & H*(10) - Considerations for Electronics Damage 1

CLIC OMPWG What are reasonable limits for such quantities?  depends on type of electronics  in any case, for SEE’s no definitive damage limit However, to indicate areas of concern, ‘LHC Future Electronics Policy study’ by the R2E Study Group at CERN classify regions around LHC according to low, medium, and high levels of dose or fluence based on the following thresholds: Simulations for Electronics Damage, H*(10) - Considerations for Electronics Damage 2 1 MeV neutrons: Low: Fluence <1  10 8 cm -2 Medium: 1  10 8 cm -2 < Fluence < 1  cm -2 High: 1  cm -2 < Fluence 20 MeV hadrons: Low: Fluence < 1  10 7 cm -2 Medium: 1  10 7 cm -2 < Fluence < 1  10 9 cm -2 High: 1  10 9 cm -2 < Fluence Dose: Low: Dose < 1Gy/y Medium: 1Gy/y < Dose < 1kGy High: 1kGy/y < Dose

CLIC OMPWG Simulations for Electronics Damage & H*(10) - FLUKA Simulations Assume Continuous Losses along main beam at 9 GeV Dose to Personnel: Simulate build up and decay of radiation over 7.5 year period, 180d beam, 185d cooling per year. Score H*(10) Electronics Damage, score: 1 MeV-neutron equivalent fluence 20 MeV Hadron Fluence Absorbed dose Preliminary Calculations:

Simulations for Electronics Damage, H*(10) - Latest QP Design CLIC OMPWG Courtesy A. Samoshkin, Nov 2009

Simulations for Electronics Damage, H*(10) - FLUKA geometry CLIC OMPWG Drive Beam Cross SectionMain Beam Cross Section 2D visualizations of FLUKA model using Flair

CLIC OMPWG Module Layout for 9 GeV Simulations for Electronics Damage, H*(10) - FLUKA geometry 2 TYPE 1 TYPE 0 3D visualization of FLUKA model using Simple Geo

CLIC OMPWG High Medium Low NORMALISATION: 180 days 1.16E12 per bunch, 50hz Losses 5E-8 m -1, Simulations for Electronics Damage, H*(10) - Example Result 1 – Absorbed Dose MB 9 GeV Gy

CLIC OMPWG High Medium Simulations for Electronics Damage, H*(10) - Example Result 2 – 1MeV Neutron Eq. Fluence NORMALISATION: 180 days 1.16E12 per bunch, 50hz Losses 5E-8 m -1, MB 9 GeV Low cm -2

CLIC OMPWG High Medium Simulations for Electronics Damage, H*(10) - Example Result 3 – < 20 MeV Hadron Fluence NORMALISATION: 180 days 1.16E12 per bunch, 50hz Losses 5E-8 m -1, MB 9 GeV Low cm -2

CLIC OMPWG Simulations for Electronics Damage, H*(10) - Example Result 4 – Ambient Dose Equiv Rates Irradiation: 7.5 years running, (cycle -180d year beam, 185d cooling) 1.16E12 per bunch, 50hz, Losses 5E-8 m -1, 7.5 years running, 1 week coolingMB 9 GeV