Interpretation and use of BLM Data B. Dehning 14.12.2005 LTC, B.Dehning

Location of Monitors (overview) IR TAS or BPM Q1 TRIPLET two beam TRIPLET abs TAN (1+5) D2 (2+8) TCL 1 TCL 2 XRP 4 locations MSI one side TDI one side TCD D one side TCL i one side MSD TCD Q TCD S Q5 Collimator DIS MB 8 prot DIS MB 11 prot DIS MB 9 ion DIS MB 10 cap ion 1 ISU 2 * IU IU 1 * IU 2 --- 2 * ISU 3 all ISU 4 5 4 * IU 6 7 8 14.12.2005 LTC, B.Dehning

Location of Loss Detectors at IP8 left right At the listed elements up to 8 detectors mounted on: Cryostat Single support Detectors: Ionisation chambers Secondary emission Detectors could be: non mask able mask able 14.12.2005 LTC, B.Dehning

Loss Distribution in the IP 7 Dispersion Suppressor Team R. Assmann Losses of off momentum particles (first and second dispersion increase) Concentration of losses at the beginning of MQ BLM on MB foreseen Beam 14.12.2005 LTC, B.Dehning

Loss Distribution in the ARC 7 to 8 Increase of losses approaching a MQ Peak in bin just before MQ End of loss at the centre of the MQ Basic assumption: transient losses will have same signature More simulation are needed to get better evidence (higher populated tertiary halo) Only beam 1 simulated yet May automatic online loss characterization possible (location, cause, beam I+II) Team R. Assmann Beam 14.12.2005 LTC, B.Dehning

Change of Aperture at MQ Losses enhanced at beginning of quadrupole, due to: Beta function maximums Dispersion function maximums Misalignments (location of bellows Beam kinks (quadrupole + cor. dipole location) Change in aperture Beam I Beam II 14.12.2005 LTC, B.Dehning

Shower development in the Cryostat L. Ponce Impact position varied along the MQ Highest signal from loss at the beginning of the MQ Position of detectors optimized to catch losses: Transition between MB – MQ Middle of MQ Transition between MQ – MB to minimize uncertainty of ratio of energy deposition in coil and detector Beam I – II discrimination Beam 14.12.2005 LTC, B.Dehning

Simulated BLM Signals at Collimators Simulation of BLM signal and crosstalk at IP3 Equivalent Simulation for IP7 started (team: A. Ferrari) signal signal crosstalk 14.12.2005 LTC, B.Dehning

BLM Signal from Upstream Collimator Igor A. Kurochkin BLM3 (close to TCS2) – only 57.4% “Good” signal BLM2 – 4% BLM4 – 9% BLM5 – 5% BLM6 – 4% BLM7 – 1% TCP1 - major contributor to background BLM2 – 96% BLM7 – 20% 7 TeV TCP 1 TCS 1 14.12.2005 LTC, B.Dehning

14.12.2005 LTC, B.Dehning

Transversal Variation of Monitor Location TCS1 Igor A. Kurochkin Best signal to cross talk at position near to the beam Foreseen detector position to be changed if simulation indicate unacceptable signal to crosstalk ratio Detector pos. beam 14.12.2005 LTC, B.Dehning

Available Beam Loss Information's Used threshold values (change with energy) Loss signals: Max values of integration intervals between 40 us and 1s updated every 1 s Several average values between 1s and 60 s updated every second Long term averages Post Mortem values 14.12.2005 LTC, B.Dehning

Beam Dump at HERA Aim of setup LHC measurement setup BLM system test Verification of Geant simulation Beam losses dynamic observations LHC measurement setup 6 chambers in top of internal dump 1 before and 1 after the dump 14.12.2005 LTC, B.Dehning

Dose Measurements at the HERA Beam Dump Protons: 1 1013 E = 920 GeV Peak corresponds to 1.5 Gy No gain switch Over 7 orders foreseen 14.12.2005 LTC, B.Dehning

Dose Measurements at the HERA Beam Dump, zoom 14.12.2005 LTC, B.Dehning

Reserve Slides 14.12.2005 LTC, B.Dehning

HERA DUMP Signal 14.12.2005 LTC, B.Dehning

14.12.2005 LTC, B.Dehning