DIPAC2011 - List of Authors (Dehning, B.)

Paper

Title

Page

A Fast CVD Diamond Beam Loss Monitor for LHC

143

E. Griesmayer, B. Dehning, D. Dobos, E. Effinger, H. Pernegger
CERN, Geneva, Switzerland

Chemical Vapour Deposition (CVD) diamond detectors were installed in the collimation area of the CERN LHC to study their feasibility as Fast Beam Loss Monitors in a high-radiation environment. The detectors were configured with a fast, radiation-hard pre-amplifier with a bandwidth of 2 GHz. The readout was via an oscilloscope with a bandwidth of 1 GHz and a sampling rate of 5 GSPS. Despite the 250 m cable run from the detectors to the oscilloscope, single MIPs were resolved with a 2 ns rise time, a pulse width of 10 ns and a time resolution of less than 1 ns. Two modes of operation were applied. For the analysis of unexpected beam aborts, the loss profile was recorded in a 1 ms buffer and, for nominal operation, the histogram of the time structure of the losses was recorded in synchronism with the LHC period of 89.2 μs. Measurements during the LHC start-up (February to December 2010) are presented. The Diamond Monitors gave an unprecedented insight into the time structure of the beam losses resolving the 400 MHz RF frequency as well as the nominal bunch separation of 25 ns. In future, these detectors will be used to study ghost bunches and particles in the 3 μs abort gap.

MOPD44

Self Testing Functionality of the LHC BLM System

152

J. Emery, B. Dehning, E. Effinger, A. Nordt, C. Zamantzas
CERN, Geneva, Switzerland

Reliability concerns have driven the design of the LHC BLM system throughout its development, from the early conceptual stage right through the commissioning phase and up to the latest development of diagnostic tools. To protect the system against non-conformities, new ways of automatic checking have been developed and implemented. These checks are regularly and systematically executed by the LHC operation team to insure that the system status after each test is "as good as new". This checks the electrical part of the detectors (ionisation chamber or secondary emission monitor), their cable connections to the front-end electronics, the connections to the back-end electronics and their ability to request a beam abort. During the installation and in the early commissioning phase, these checks proved invaluable in finding non-conformities caused by unexpected failures. This paper will describe these checks in detail, commenting on the latest performance and the typical non-conformities detected. A statistical analysis of the LHC BLM system will also be presented to show the evolution of the various system parameters.

Poster MOPD44 [2.068 MB]

TUPD44

LHC Beam Loss Monitoring System Verification Applications

404

E. Fadakis, B. Dehning, S. Jackson, C. Zamantzas
CERN, Geneva, Switzerland

The LHC Beam Loss Monitoring (BLM) system is one of the most complex instrumentation systems deployed in the LHC. In addition to protecting the collider, the system also needs to provide a means of diagnosing machine faults and deliver a feedback of losses to the control room as well as to several systems for their setup and analysis. It has to transmit and process signals from almost 4’000 monitors, and has nearly 3 million configurable parameters. The system was designed with reliability and availability in mind. The specified operation and the fail-safety standards must be guaranteed for the system to perform its function in preventing superconductive magnet destruction caused by particle flux. Maintaining the expected reliability requires extensive testing and verification. In this paper we report our most recent additions to the numerous verification applications. The developments have been made using LabVIEW and CERN custom made libraries and allow the user to connect either directly to the front end computer (FEC) or through a dedicated server.

TUPD64

Test Measurements of a 20 m/s Carbon Wire Beam Scanner

452

M. Koujili, J. De Freitas, B. Dehning, J. Emery, J.F. Herranz Alvarez, D. Ramos, M. Sapinski
CERN, Geneva, Switzerland
Y. Ait Amira
UFC, Besançon, France
A. Djerdir
UTBM, Belfort, France

This paper presents the design of the actuator for the fast and high accuracy Wire Scanner system. The actuator consists of a rotary brush-less synchronous motor with the permanent magnet rotor installed inside the vacuum chamber and the stator installed outside. The fork, permanent magnet rotor and two angular position sensors are mounted on the same axis and located inside the beam vacuum chamber. The system has to resist a bake-out temperature of 200°C and ionizing radiation up to tenths of kGy/year. Maximum wire travelling speed of 20 m/s and a position measurement accuracy of 4 μm is required. Therefore, the system must avoid generating vibration and electromagnetic interference. A digital feedback controller will allow maximum flexibility for the loop parameters and feeds the 3-phase linear power driver. The performance of the presented design is investigated through simulations and experimental tests.

Paper	Title	Page
MOPD41	A Fast CVD Diamond Beam Loss Monitor for LHC	143
	E. Griesmayer, B. Dehning, D. Dobos, E. Effinger, H. Pernegger CERN, Geneva, Switzerland
	Chemical Vapour Deposition (CVD) diamond detectors were installed in the collimation area of the CERN LHC to study their feasibility as Fast Beam Loss Monitors in a high-radiation environment. The detectors were configured with a fast, radiation-hard pre-amplifier with a bandwidth of 2 GHz. The readout was via an oscilloscope with a bandwidth of 1 GHz and a sampling rate of 5 GSPS. Despite the 250 m cable run from the detectors to the oscilloscope, single MIPs were resolved with a 2 ns rise time, a pulse width of 10 ns and a time resolution of less than 1 ns. Two modes of operation were applied. For the analysis of unexpected beam aborts, the loss profile was recorded in a 1 ms buffer and, for nominal operation, the histogram of the time structure of the losses was recorded in synchronism with the LHC period of 89.2 μs. Measurements during the LHC start-up (February to December 2010) are presented. The Diamond Monitors gave an unprecedented insight into the time structure of the beam losses resolving the 400 MHz RF frequency as well as the nominal bunch separation of 25 ns. In future, these detectors will be used to study ghost bunches and particles in the 3 μs abort gap.

MOPD44	Self Testing Functionality of the LHC BLM System	152
	J. Emery, B. Dehning, E. Effinger, A. Nordt, C. Zamantzas CERN, Geneva, Switzerland
	Reliability concerns have driven the design of the LHC BLM system throughout its development, from the early conceptual stage right through the commissioning phase and up to the latest development of diagnostic tools. To protect the system against non-conformities, new ways of automatic checking have been developed and implemented. These checks are regularly and systematically executed by the LHC operation team to insure that the system status after each test is "as good as new". This checks the electrical part of the detectors (ionisation chamber or secondary emission monitor), their cable connections to the front-end electronics, the connections to the back-end electronics and their ability to request a beam abort. During the installation and in the early commissioning phase, these checks proved invaluable in finding non-conformities caused by unexpected failures. This paper will describe these checks in detail, commenting on the latest performance and the typical non-conformities detected. A statistical analysis of the LHC BLM system will also be presented to show the evolution of the various system parameters.
	Poster MOPD44 [2.068 MB]

TUPD44	LHC Beam Loss Monitoring System Verification Applications	404
	E. Fadakis, B. Dehning, S. Jackson, C. Zamantzas CERN, Geneva, Switzerland
	The LHC Beam Loss Monitoring (BLM) system is one of the most complex instrumentation systems deployed in the LHC. In addition to protecting the collider, the system also needs to provide a means of diagnosing machine faults and deliver a feedback of losses to the control room as well as to several systems for their setup and analysis. It has to transmit and process signals from almost 4’000 monitors, and has nearly 3 million configurable parameters. The system was designed with reliability and availability in mind. The specified operation and the fail-safety standards must be guaranteed for the system to perform its function in preventing superconductive magnet destruction caused by particle flux. Maintaining the expected reliability requires extensive testing and verification. In this paper we report our most recent additions to the numerous verification applications. The developments have been made using LabVIEW and CERN custom made libraries and allow the user to connect either directly to the front end computer (FEC) or through a dedicated server.

TUPD64	Test Measurements of a 20 m/s Carbon Wire Beam Scanner	452
	M. Koujili, J. De Freitas, B. Dehning, J. Emery, J.F. Herranz Alvarez, D. Ramos, M. Sapinski CERN, Geneva, Switzerland Y. Ait Amira UFC, Besançon, France A. Djerdir UTBM, Belfort, France
	This paper presents the design of the actuator for the fast and high accuracy Wire Scanner system. The actuator consists of a rotary brush-less synchronous motor with the permanent magnet rotor installed inside the vacuum chamber and the stator installed outside. The fork, permanent magnet rotor and two angular position sensors are mounted on the same axis and located inside the beam vacuum chamber. The system has to resist a bake-out temperature of 200°C and ionizing radiation up to tenths of kGy/year. Maximum wire travelling speed of 20 m/s and a position measurement accuracy of 4 μm is required. Therefore, the system must avoid generating vibration and electromagnetic interference. A digital feedback controller will allow maximum flexibility for the loop parameters and feeds the 3-phase linear power driver. The performance of the presented design is investigated through simulations and experimental tests.