HB2012 - List of Authors (Griesmayer, E.)

Paper	Title	Page
MOP203	Bunch-by-Bunch Beam Loss Diagnostics with Diamond Detectors at the LHC	41
	M. Hempel BTU, Cottbus, Germany T. Baer University of Hamburg, Hamburg, Germany S. Bart Pedersen, B. Dehning, E. Effinger, E. Griesmayer, A. Lechner, R. Schmidt CERN, Geneva, Switzerland W. Lohmann DESY, Hamburg, Germany
	A main challenge in the operation with high intensity beams is managing beam losses that imply the risk of quenching superconducting magnets or even damage equipment. There are various sources of beam losses, such as losses related to injection, to beam instabilities and to UFOs (Unidentified Falling Objects). Mostly surprising in the first years of LHC operation was the observation of UFOs. They are believed to be dust particles with a typical size of 1-100 um, which lead to beam losses with a duration of about ten revolutions when they fall into the beam. 3600 BLMs (Beam Loss Monitors) are installed around the LHC ring, allowing to determinate the accurate location of UFOs. The time resolution of the BLMs is 40 us (half a turn revolution). A measurement of the beam losses with a time resolution better than the bunch spacing of 50 ns is crucial to understand loss mechanisms. Diamond sensors are able to provide such diagnostics and perform particle counting with ns time resolution. In this paper, we present measurements of various types of beam losses with diamond detectors. We also compare measurements of UFO induced beam losses around the LHC ring with results from MadX simulations.

MOP241	An Experiment on Hydrodynamic Tunnelling of the SPS High Intensity Proton Beam at the HiRadMat Facility	141
	J. Blanco, F. Burkart, N. Charitonidis, I. Efthymiopoulos, D. Grenier, C. Maglioni, R. Schmidt, C. Theis, D. Wollmann CERN, Geneva, Switzerland E. Griesmayer CIVIDEC Instrumentation, Wien, Austria N.A. Tahir GSI, Darmstadt, Germany
	The LHC will collide proton beams with an energy stored in each beam of 362 MJ. To predict damage for a catastrophic failure of the protections systems, simulation studies of the impact of an LHC beam on copper targets were performed. Firstly, the energy deposition of the first bunches in a target with FLUKA is calculated. The effect of the energy deposition on the target is then calculated with a hydrodynamic code, BIG2. The impact of only a few bunches leads to a change of target density. The calculations are done iteratively in several steps and show that such beam can tunnel up to 30-35 m into a target. Similar simulations for the SPS beam also predict hydrodynamic tunnelling. An experiment at the HiRadMat (High Radiation Materials) at CERN using the proton beam from the Super Proton Synchrotron (SPS) is performed to validate the simulations. The particle energy in the SPS beam is 440 GeV and has up to 288 bunches. Significant hydrodynamic tunnelling due to hydrodynamic effects are expected. First experiments are planned for July 2012. Simulation results, the experimental setup and the outcome of the tests will be reported at this workshop.

Paper

Title

Page

Bunch-by-Bunch Beam Loss Diagnostics with Diamond Detectors at the LHC

41

M. Hempel
BTU, Cottbus, Germany
T. Baer
University of Hamburg, Hamburg, Germany
S. Bart Pedersen, B. Dehning, E. Effinger, E. Griesmayer, A. Lechner, R. Schmidt
CERN, Geneva, Switzerland
W. Lohmann
DESY, Hamburg, Germany

A main challenge in the operation with high intensity beams is managing beam losses that imply the risk of quenching superconducting magnets or even damage equipment. There are various sources of beam losses, such as losses related to injection, to beam instabilities and to UFOs (Unidentified Falling Objects). Mostly surprising in the first years of LHC operation was the observation of UFOs. They are believed to be dust particles with a typical size of 1-100 um, which lead to beam losses with a duration of about ten revolutions when they fall into the beam. 3600 BLMs (Beam Loss Monitors) are installed around the LHC ring, allowing to determinate the accurate location of UFOs. The time resolution of the BLMs is 40 us (half a turn revolution). A measurement of the beam losses with a time resolution better than the bunch spacing of 50 ns is crucial to understand loss mechanisms. Diamond sensors are able to provide such diagnostics and perform particle counting with ns time resolution. In this paper, we present measurements of various types of beam losses with diamond detectors. We also compare measurements of UFO induced beam losses around the LHC ring with results from MadX simulations.

MOP241

An Experiment on Hydrodynamic Tunnelling of the SPS High Intensity Proton Beam at the HiRadMat Facility

141

J. Blanco, F. Burkart, N. Charitonidis, I. Efthymiopoulos, D. Grenier, C. Maglioni, R. Schmidt, C. Theis, D. Wollmann
CERN, Geneva, Switzerland
E. Griesmayer
CIVIDEC Instrumentation, Wien, Austria
N.A. Tahir
GSI, Darmstadt, Germany

The LHC will collide proton beams with an energy stored in each beam of 362 MJ. To predict damage for a catastrophic failure of the protections systems, simulation studies of the impact of an LHC beam on copper targets were performed. Firstly, the energy deposition of the first bunches in a target with FLUKA is calculated. The effect of the energy deposition on the target is then calculated with a hydrodynamic code, BIG2. The impact of only a few bunches leads to a change of target density. The calculations are done iteratively in several steps and show that such beam can tunnel up to 30-35 m into a target. Similar simulations for the SPS beam also predict hydrodynamic tunnelling. An experiment at the HiRadMat (High Radiation Materials) at CERN using the proton beam from the Super Proton Synchrotron (SPS) is performed to validate the simulations. The particle energy in the SPS beam is 440 GeV and has up to 288 bunches. Significant hydrodynamic tunnelling due to hydrodynamic effects are expected. First experiments are planned for July 2012. Simulation results, the experimental setup and the outcome of the tests will be reported at this workshop.