IBIC2012 - Classification: Beam Loss Detection

Paper

Title

Page

Comparison of Three Different Concepts of High Dynamic Range and Dependability Optimised Current Measurement Digitisers for Beam Loss Systems

1

W. Vigano, B. Dehning, E. Effinger, G.G. Venturini, C. Zamantzas
CERN, Geneva, Switzerland

The first concept is based on current to frequency conversion, enhanced with an ADC for extending the dynamic range and decreasing the response time. A summary of 3 years worth of operational experience with such a system for LHC beam loss monitoring will be given. The second principle is based on an adaptive current to frequency converter implemented in an ASIC. The basic parameters of the circuit are discussed and compared with measurements. Several measures are taken to harden both circuits against single event effects and to make them tolerant for operation in radioactive environments. The third circuit is based on a fully differential integrator for enhanced dynamic range, where laboratory and test installation measurements will be presented. All circuits are designed to avoid any dead time in the acquisition and have reliability and fail safe operational considerations taken into account.

MOPA10

Diamond Detectors for LHC

1

E. Griesmayer
CIVIDEC Instrumentation, Wien, Austria
B. Dehning
CERN, Geneva, Switzerland

Funding: CIVIDEC Instrumentation GmbH
Diamond detectors are installed at the LHC as fast beam loss monitors. Their excellent time resolution make them a useful beam diagnostic tool for bunch-to-bunch beam loss observations, which is essential for the understanding of fast beam loss scenarios at the LHC.

MOPA12

Characterization of a Wide Dynamic-range, Radiation-tolerant Charge-digitizer ASIC for Monitoring of Beam Losses

1

G.G. Venturini, F. Anghinolfi, B. Dehning
CERN, Geneva, Switzerland
M. Kayal
EPFL, Lausanne, Switzerland

An Application Specific Integrated Circuit (ASIC) has been designed and fabricated to provide a compact solution to digitize current signals from ionization chambers and diamond detectors, employed as beam loss monitors at CERN and several other high energy physics facilities. The circuit topology has been devised to accept positive and negative currents, to have a wide dynamic range (above 120 dB), withstand radiation levels over 100kGy and offer different modes of operation, covering a broad range of applications. Furthermore, an internal conversion reference is employed in the digitization, to provide an accurate absolute measurement. This paper discusses the detailed characterization of the first prototype: linearity, radiation tolerance and temperature dependence of the conversion, as well as implications and system-level considerations regarding its use for beam instrumentation applications in a high energy physics facility.

TUPA08

Application of Single Crystal Diamonds (scCVD) as Beam Conditions Monitors at LHC

1

M.E. Castro Carballo
DESY Zeuthen, Zeuthen, Germany

The properties of the single-crystal diamond (scCVD): radiation hardness, low leakage current and fast signal, make it suitable for use as a particle detector in areas of high radiation dose. The Beam Conditions and Radiation Monitoring system (BRM) of the CMS experiment has a monitor (BCM1F) consisting of 4 modules located 1.8 m away from the interaction point, on both sides. Each module contains a sensor, radiation hard FEE and optical transmission of the signal. It counts single particles of beam halo, beam-gas, machine induced background, and collision products. The BRM protects CMS from high beam losses and provides feedback to the LHC and CMS on the beam conditions. The BCM1F sub-detector is very helpful as it is able to provide different background information together with luminosity correlations. Additional scCVD sensors are being installed in the LHC ring to be used as BLMs. The new BLM system (BCM1F4LHC) will be composed of 8 diamonds in points likely to suffer from beam losses. Nowadays, four sensors deliver information of hit rates that are correlated to the existing BLMs. A characterization of both BCM1F systems is presented.

TUPA09

Architecture of the System for Beam Loss Monitoring and Measurements under Development for the Injector Complex at CERN

C. Zamantzas, M. Alsdorf, B. Dehning, S. Jackson, M. Kwiatkowski, W. Vigano
CERN, Geneva, Switzerland

The strategy for beam setup and machine protection of the accelerators at the European Organisation for Nuclear Research (CERN) is mainly based on its Beam Loss Monitoring (BLM) systems. For their upgrade to higher beam energies and intensities, a new BLM system is under development with the aim of providing faster measurement updates with higher dynamic range and the ability to accept more types of detectors as input compared to its predecessors. In this paper, the architecture of the complete system is explored giving an insight to the design choices made to provide a highly reconfigurable system that is able to fulfil the different requirements of each accelerator using reprogrammable devices.

TUPA10

Development of Optical Fiber Beam Loss Monitor System for the KEK Photon Factory

T. Obina, Y. Yano
KEK, Ibaraki, Japan

Beam loss monitor system using optical fibers has been developed to determine the loss point of the injected beam at the KEK Photon Factory (PF) electron storage ring. Large-core optical fiber was installed along the vacuum chamber of the storage ring, of which circumference is about 187m. In order to cover the whole location, total 10 optical fibers with the length of 30 m is used. Both ends of the fiber has been fed out of the radiation shield of the ring. The Cherenkov light produced by the electron which is not captured in the ring, is detected by a photomultiplier tube (PMT) attached on the upstream side of the fiber. Rise-time of the PMT of 5 ns is fast enough to determine the location of the beam loss point. In the KEK-PF, two kinds of injection system, kicker magnets and a pulsed sextupole magnet (PSM), has been used for the routine operation. In this paper, details of the loss monitor system are reported and the difference of the two injection system will be discussed.

WEIB02

Review of Reliability Concepts Applied to Beam Loss Monitoring Systems

B. Dehning
CERN, Geneva, Switzerland

Beam loss measurement systems are often used for the protection of equipment against the damage caused by impacting particles creating secondary showers and their energy dissipation in the matter. Depending on the acceptable consequences and the frequency of particle impact events on equipment reliability requirements are scaling accordingly. Increasing reliability often leads to more complex systems. The downside of complexity is a reduction of availability, therefore an optimum has to be found for these conflicting requirements. A detailed review of selected concepts and solutions from real-life examples will be given to show approaches used in various parts of the system from the sensors, signal processing, and software implementations up to the requirements for operation and documentation.

Paper	Title	Page
MOPA09	Comparison of Three Different Concepts of High Dynamic Range and Dependability Optimised Current Measurement Digitisers for Beam Loss Systems	1
	W. Vigano, B. Dehning, E. Effinger, G.G. Venturini, C. Zamantzas CERN, Geneva, Switzerland
	The first concept is based on current to frequency conversion, enhanced with an ADC for extending the dynamic range and decreasing the response time. A summary of 3 years worth of operational experience with such a system for LHC beam loss monitoring will be given. The second principle is based on an adaptive current to frequency converter implemented in an ASIC. The basic parameters of the circuit are discussed and compared with measurements. Several measures are taken to harden both circuits against single event effects and to make them tolerant for operation in radioactive environments. The third circuit is based on a fully differential integrator for enhanced dynamic range, where laboratory and test installation measurements will be presented. All circuits are designed to avoid any dead time in the acquisition and have reliability and fail safe operational considerations taken into account.

MOPA10	Diamond Detectors for LHC	1
	E. Griesmayer CIVIDEC Instrumentation, Wien, Austria B. Dehning CERN, Geneva, Switzerland
	Funding: CIVIDEC Instrumentation GmbH Diamond detectors are installed at the LHC as fast beam loss monitors. Their excellent time resolution make them a useful beam diagnostic tool for bunch-to-bunch beam loss observations, which is essential for the understanding of fast beam loss scenarios at the LHC.

MOPA12	Characterization of a Wide Dynamic-range, Radiation-tolerant Charge-digitizer ASIC for Monitoring of Beam Losses	1
	G.G. Venturini, F. Anghinolfi, B. Dehning CERN, Geneva, Switzerland M. Kayal EPFL, Lausanne, Switzerland
	An Application Specific Integrated Circuit (ASIC) has been designed and fabricated to provide a compact solution to digitize current signals from ionization chambers and diamond detectors, employed as beam loss monitors at CERN and several other high energy physics facilities. The circuit topology has been devised to accept positive and negative currents, to have a wide dynamic range (above 120 dB), withstand radiation levels over 100kGy and offer different modes of operation, covering a broad range of applications. Furthermore, an internal conversion reference is employed in the digitization, to provide an accurate absolute measurement. This paper discusses the detailed characterization of the first prototype: linearity, radiation tolerance and temperature dependence of the conversion, as well as implications and system-level considerations regarding its use for beam instrumentation applications in a high energy physics facility.

TUPA08	Application of Single Crystal Diamonds (scCVD) as Beam Conditions Monitors at LHC	1
	M.E. Castro Carballo DESY Zeuthen, Zeuthen, Germany
	The properties of the single-crystal diamond (scCVD): radiation hardness, low leakage current and fast signal, make it suitable for use as a particle detector in areas of high radiation dose. The Beam Conditions and Radiation Monitoring system (BRM) of the CMS experiment has a monitor (BCM1F) consisting of 4 modules located 1.8 m away from the interaction point, on both sides. Each module contains a sensor, radiation hard FEE and optical transmission of the signal. It counts single particles of beam halo, beam-gas, machine induced background, and collision products. The BRM protects CMS from high beam losses and provides feedback to the LHC and CMS on the beam conditions. The BCM1F sub-detector is very helpful as it is able to provide different background information together with luminosity correlations. Additional scCVD sensors are being installed in the LHC ring to be used as BLMs. The new BLM system (BCM1F4LHC) will be composed of 8 diamonds in points likely to suffer from beam losses. Nowadays, four sensors deliver information of hit rates that are correlated to the existing BLMs. A characterization of both BCM1F systems is presented.

TUPA09	Architecture of the System for Beam Loss Monitoring and Measurements under Development for the Injector Complex at CERN
	C. Zamantzas, M. Alsdorf, B. Dehning, S. Jackson, M. Kwiatkowski, W. Vigano CERN, Geneva, Switzerland
	The strategy for beam setup and machine protection of the accelerators at the European Organisation for Nuclear Research (CERN) is mainly based on its Beam Loss Monitoring (BLM) systems. For their upgrade to higher beam energies and intensities, a new BLM system is under development with the aim of providing faster measurement updates with higher dynamic range and the ability to accept more types of detectors as input compared to its predecessors. In this paper, the architecture of the complete system is explored giving an insight to the design choices made to provide a highly reconfigurable system that is able to fulfil the different requirements of each accelerator using reprogrammable devices.

TUPA10	Development of Optical Fiber Beam Loss Monitor System for the KEK Photon Factory
	T. Obina, Y. Yano KEK, Ibaraki, Japan
	Beam loss monitor system using optical fibers has been developed to determine the loss point of the injected beam at the KEK Photon Factory (PF) electron storage ring. Large-core optical fiber was installed along the vacuum chamber of the storage ring, of which circumference is about 187m. In order to cover the whole location, total 10 optical fibers with the length of 30 m is used. Both ends of the fiber has been fed out of the radiation shield of the ring. The Cherenkov light produced by the electron which is not captured in the ring, is detected by a photomultiplier tube (PMT) attached on the upstream side of the fiber. Rise-time of the PMT of 5 ns is fast enough to determine the location of the beam loss point. In the KEK-PF, two kinds of injection system, kicker magnets and a pulsed sextupole magnet (PSM), has been used for the routine operation. In this paper, details of the loss monitor system are reported and the difference of the two injection system will be discussed.

WEIB02	Review of Reliability Concepts Applied to Beam Loss Monitoring Systems
	B. Dehning CERN, Geneva, Switzerland
	Beam loss measurement systems are often used for the protection of equipment against the damage caused by impacting particles creating secondary showers and their energy dissipation in the matter. Depending on the acceptable consequences and the frequency of particle impact events on equipment reliability requirements are scaling accordingly. Increasing reliability often leads to more complex systems. The downside of complexity is a reduction of availability, therefore an optimum has to be found for these conflicting requirements. A detailed review of selected concepts and solutions from real-life examples will be given to show approaches used in various parts of the system from the sensors, signal processing, and software implementations up to the requirements for operation and documentation.