IPAC2014 - List of Authors (Shetty, N.V.)

Paper	Title	Page
MOOCB01	Beam-induced Quench Tests of LHC Magnets	52
	M. Sapinski, B. Auchmann, T. Bär, W. Bartmann, M. Bednarek, S. Bozyigit, C. Bracco, R. Bruce, F. Cerutti, V. Chetvertkova, K. Dahlerup-Petersen, B. Dehning, E. Effinger, J. Emery, A. Guerrero, E.B. Holzer, W. Höfle, A. Lechner, A. Priebe, S. Redaelli, B. Salvachua, R. Schmidt, N.V. Shetty, A.P. Siemko, E. Skordis, M. Solfaroli Camillocci, J. Steckert, J.A. Uythoven, D. Valuch, A.P. Verweij, J. Wenninger, D. Wollmann, M. Zerlauth, E.N. del Busto CERN, Geneva, Switzerland
	At the end of the LHC Run1 a 48-hour quench-test campaign took place to investigate the quench levels of superconducting magnets for loss durations from nanoseconds to tens of seconds. The longitudinal losses produced extended from one meter to hundreds of meters and the number of lost protons varied from 10⁸ to 10¹³. The results of these and other, previously conducted quench experiments, allow the quench levels of several types of LHC magnets under various loss conditions to be assessed. The quench levels are expected to limit LHC performance in the case of steady-state losses in the interaction regions and also in the case of fast losses initiated by dust particles all around the ring. It is therefore required to accurately adjust beam loss abort thresholds in order to maximize the operation time. A detailed discussion of these quench test results and a proposal for additional tests after the LHC restart is presented.
	Slides MOOCB01 [2.737 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOOCB01
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MOPRO019	Energy Deposition and Quench Level Calculations for Millisecond and Steady-state Quench Tests of LHC Arc Quadrupoles at 4 TeV	105
	N.V. Shetty, B. Auchmann, V. Chetvertkova, A. Lechner, A. Priebe, M. Sapinski, A.P. Verweij, D. Wollmann CERN, Geneva, Switzerland
	In 2013, beam-induced quench tests with 4 TeV protons were performed to probe the quench level of LHC arc quadrupole magnets at timescales corresponding to millisecond beam losses and steady-state losses. As the energy deposition in magnet coils cannot be measured directly, this study presents corresponding FLUKA simulations as well as estimates of quench levels derived with the QP3 code. Furthermore, beam loss monitor (BLM) signals were simulated and benchmarked against the measurements. Simulated and measured BLM signals are generally found to agree within 30 percent.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO019
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MOPRO020	FLUKA Simulation of Particle Fluences to ALICE due to LHC Injection Kicker Failures	109
	N.V. Shetty, C. Bracco, A. Di Mauro, A. Lechner, E. Leogrande, J.A. Uythoven CERN, Geneva, Switzerland
	The counter-rotating beams of the LHC are injected in insertion regions which also accommodate the ALICE and LHCb experiments. An assembly of beam absorbers ensures the protection of machine elements in case of injection kicker failures, which can affect either the injected or the stored beam. In the first years of LHC operation, secondary particle showers due to beam impact on the injection beam stopper caused damage to the MOS injectors of the ALICE silicon drift detector as well as high-voltage trips in other ALICE subdetectors. In this study, we present FLUKA simulations of particle fluences to the ALICE cavern for injection failures encountered during operation. Two different cases are reported, one where the miskicked beam is fully intercepted and one where the beam grazes the beam stopper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO020
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MOPRO021	Power Deposition in LHC Magnets With and Without Dispersion Suppressor Collimators Downstream of the Betatron Cleaning Insertion	112
	A. Lechner, B. Auchmann, R. Bruce, F. Cerutti, P.P. Granieri, A. Marsili, S. Redaelli, N.V. Shetty, E. Skordis, G.E. Steele, A.P. Verweij CERN, Geneva, Switzerland
	The power deposited in dispersion suppressor (DS) magnets downstream of the LHC betatron cleaning insertion is governed by off-momentum protons which predominantly originate from single-diffractive interactions in primary collimators. With higher beam energy and intensities anticipated in future operation, these clustered proton losses could possibly induce magnet quenches during periods of short beam lifetime. In this paper, we present FLUKA simulations for nominal 7 TeV operation, comparing the existing layout with alternative layouts where selected DS dipoles are substituted by pairs of shorter higher-field magnets and a collimator. Power densities predicted for different collimator settings are compared against present estimates of quench limits. Further, the expected reduction factor due to DS collimators is evaluated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO021
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MOPRO032	Upgrades to the LHC Injection and Beam Dumping Systems for the HL-LHC Project	141
	J.A. Uythoven, M.J. Barnes, B. Goddard, J. Hrivnak, A. Lechner, F.L. Maciariello, A. Mereghetti, A. Perillo Marcone, N.V. Shetty, G.E. Steele CERN, Geneva, Switzerland
	The HL-LHC project will push the performance of the LHC injection and beam dumping systems towards new limits. This paper describes the systems affected and presents the new beam parameters for these systems. It also describes the studies to be performed to determine which sub-components of these systems need to be upgraded to fulfill the new HL-LHC requirements. The results from the preliminary upgrade studies for the injection absorbers TDI are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO032
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TUPRO020	Integration of a Neutral Absorber for the LHC Point 8	1052
	A. Santamaría García, R. Alemany-Fernández, H. Burkhardt, F. Cerutti, L.S. Esposito, N.V. Shetty CERN, Geneva, Switzerland
	The LHCb detector will be upgraded during the second long shutdown (LS2) of the LHC machine, in order to increase its statistical precision significantly. The upgraded LHCb foresees a peak luminosity of L = 1-2 . 10³³ cm^-2 s⁻¹, with a pileup of 5. This represents ten times more luminosity and five times more pile up than in the present LHC. With these conditions, the pp-collisions and beam losses will produce a non-negligeable beam-induced energy deposition in the interaction region. More precisely, studies have shown that the energy deposition will especially increase on the D2 recombination dipole, which could bring them close to their safety thresholds. To avoid this, the placement of a minimal neutral absorber has been proposed. This absorber will have the same role as the TAN in the high luminosity Interaction Regions (IR) 1 and 5. This study shows the possible dimensions and location of this absorber, and how it would reduce both the peak power density and total heat load.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO020
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TUPRO027	First Beam Background Simulation Studies at IR1 for High Luminosity LHC	1074
	R. Kwee-Hinzmann, S.M. Gibson JAI, Egham, Surrey, United Kingdom G. Bregliozzi, R. Bruce, F. Cerutti, L.S. Esposito, R. Kersevan, A. Lechner, N.V. Shetty CERN, Geneva, Switzerland S.M. Gibson Royal Holloway, University of London, Surrey, United Kingdom
	In the High-Luminosity Large Hadron Collider (HL-LHC) Project, the LHC will be significantly upgraded to attain a peak luminosity of up to 8.5 × 10³⁴ cm^-2s^-1, thus almost an order of magnitude higher compared to the nominal machine configuration in ATLAS at IP1 and CMS at IP5. In the view of a successful machine setup as well as a successful physics programme, beam induced background studies at IP1 were performed to investigate sources of particle fluxes to the experimental area. In particular as a start of the study, two sources forming the major contributions were simulated in detail: the first one considers inelastic interactions from beam particles hitting tertiary collimators, the second one from beam interactions with residual gas-molecules in the vacuum pipe close by the experiment, referred to as beam-halo and local beam-gas, respectively. We will present these first HL-LHC background studies based on SixTrack and FLUKA simulations, highlighting the simulation setup for the design case in the HL-LHC scenario. Results of particle spectra entering the ATLAS detector region are presented for the latest study version of HL-LHC machine layout (2013).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO027
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WEPRI092	Test and Simulation Results for Quenches Induced by Fast Losses on a LHC Quadrupole	2706
	C. Bracco, B. Auchmann, W. Bartmann, M. Bednarek, A. Lechner, M. Sapinski, R. Schmidt, N.V. Shetty, M. Solfaroli Camillocci, A.P. Verweij CERN, Geneva, Switzerland
	A test program for beam induced quenches was started in the LHC in 2011 in order to reduce as much as possible BLM-triggered beam dumps, without jeopardizing the safety of the superconducting magnets. A first measurement was performed to assess the quench level of a quadrupole located in the LHC injection region in case of fast (ns) losses. It consisted in dumping single bunches onto an injection protection collimator located right upstream of the quadrupole, varying the bunch intensity up to 3·10¹⁰ protons and ramping the quadrupole current up to 2200 A. No quench was recorded at that time. The test was repeated in 2013 with increased bunch intensity (6·10¹⁰ protons); a quench occurred when powering the magnet at 2500 A. The comparison between measurements during beam induced and quench heaters induced quenches is shown. Results of FLUKA simulations on energy deposition, calculations on quench behaviour using QP3 and the respective estimates of quench levels are also presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI092
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Beam-induced Quench Tests of LHC Magnets

52

M. Sapinski, B. Auchmann, T. Bär, W. Bartmann, M. Bednarek, S. Bozyigit, C. Bracco, R. Bruce, F. Cerutti, V. Chetvertkova, K. Dahlerup-Petersen, B. Dehning, E. Effinger, J. Emery, A. Guerrero, E.B. Holzer, W. Höfle, A. Lechner, A. Priebe, S. Redaelli, B. Salvachua, R. Schmidt, N.V. Shetty, A.P. Siemko, E. Skordis, M. Solfaroli Camillocci, J. Steckert, J.A. Uythoven, D. Valuch, A.P. Verweij, J. Wenninger, D. Wollmann, M. Zerlauth, E.N. del Busto
CERN, Geneva, Switzerland

At the end of the LHC Run1 a 48-hour quench-test campaign took place to investigate the quench levels of superconducting magnets for loss durations from nanoseconds to tens of seconds. The longitudinal losses produced extended from one meter to hundreds of meters and the number of lost protons varied from 10⁸ to 10¹³. The results of these and other, previously conducted quench experiments, allow the quench levels of several types of LHC magnets under various loss conditions to be assessed. The quench levels are expected to limit LHC performance in the case of steady-state losses in the interaction regions and also in the case of fast losses initiated by dust particles all around the ring. It is therefore required to accurately adjust beam loss abort thresholds in order to maximize the operation time. A detailed discussion of these quench test results and a proposal for additional tests after the LHC restart is presented.

Slides MOOCB01 [2.737 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOOCB01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO019

Energy Deposition and Quench Level Calculations for Millisecond and Steady-state Quench Tests of LHC Arc Quadrupoles at 4 TeV

105

N.V. Shetty, B. Auchmann, V. Chetvertkova, A. Lechner, A. Priebe, M. Sapinski, A.P. Verweij, D. Wollmann
CERN, Geneva, Switzerland

In 2013, beam-induced quench tests with 4 TeV protons were performed to probe the quench level of LHC arc quadrupole magnets at timescales corresponding to millisecond beam losses and steady-state losses. As the energy deposition in magnet coils cannot be measured directly, this study presents corresponding FLUKA simulations as well as estimates of quench levels derived with the QP3 code. Furthermore, beam loss monitor (BLM) signals were simulated and benchmarked against the measurements. Simulated and measured BLM signals are generally found to agree within 30 percent.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO020

FLUKA Simulation of Particle Fluences to ALICE due to LHC Injection Kicker Failures

109

N.V. Shetty, C. Bracco, A. Di Mauro, A. Lechner, E. Leogrande, J.A. Uythoven
CERN, Geneva, Switzerland

The counter-rotating beams of the LHC are injected in insertion regions which also accommodate the ALICE and LHCb experiments. An assembly of beam absorbers ensures the protection of machine elements in case of injection kicker failures, which can affect either the injected or the stored beam. In the first years of LHC operation, secondary particle showers due to beam impact on the injection beam stopper caused damage to the MOS injectors of the ALICE silicon drift detector as well as high-voltage trips in other ALICE subdetectors. In this study, we present FLUKA simulations of particle fluences to the ALICE cavern for injection failures encountered during operation. Two different cases are reported, one where the miskicked beam is fully intercepted and one where the beam grazes the beam stopper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO021

Power Deposition in LHC Magnets With and Without Dispersion Suppressor Collimators Downstream of the Betatron Cleaning Insertion

112

A. Lechner, B. Auchmann, R. Bruce, F. Cerutti, P.P. Granieri, A. Marsili, S. Redaelli, N.V. Shetty, E. Skordis, G.E. Steele, A.P. Verweij
CERN, Geneva, Switzerland

The power deposited in dispersion suppressor (DS) magnets downstream of the LHC betatron cleaning insertion is governed by off-momentum protons which predominantly originate from single-diffractive interactions in primary collimators. With higher beam energy and intensities anticipated in future operation, these clustered proton losses could possibly induce magnet quenches during periods of short beam lifetime. In this paper, we present FLUKA simulations for nominal 7 TeV operation, comparing the existing layout with alternative layouts where selected DS dipoles are substituted by pairs of shorter higher-field magnets and a collimator. Power densities predicted for different collimator settings are compared against present estimates of quench limits. Further, the expected reduction factor due to DS collimators is evaluated.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO032

Upgrades to the LHC Injection and Beam Dumping Systems for the HL-LHC Project

141

J.A. Uythoven, M.J. Barnes, B. Goddard, J. Hrivnak, A. Lechner, F.L. Maciariello, A. Mereghetti, A. Perillo Marcone, N.V. Shetty, G.E. Steele
CERN, Geneva, Switzerland

The HL-LHC project will push the performance of the LHC injection and beam dumping systems towards new limits. This paper describes the systems affected and presents the new beam parameters for these systems. It also describes the studies to be performed to determine which sub-components of these systems need to be upgraded to fulfill the new HL-LHC requirements. The results from the preliminary upgrade studies for the injection absorbers TDI are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO032

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO020

Integration of a Neutral Absorber for the LHC Point 8

1052

A. Santamaría García, R. Alemany-Fernández, H. Burkhardt, F. Cerutti, L.S. Esposito, N.V. Shetty
CERN, Geneva, Switzerland

The LHCb detector will be upgraded during the second long shutdown (LS2) of the LHC machine, in order to increase its statistical precision significantly. The upgraded LHCb foresees a peak luminosity of L = 1-2 . 10³³ cm^-2 s⁻¹, with a pileup of 5. This represents ten times more luminosity and five times more pile up than in the present LHC. With these conditions, the pp-collisions and beam losses will produce a non-negligeable beam-induced energy deposition in the interaction region. More precisely, studies have shown that the energy deposition will especially increase on the D2 recombination dipole, which could bring them close to their safety thresholds. To avoid this, the placement of a minimal neutral absorber has been proposed. This absorber will have the same role as the TAN in the high luminosity Interaction Regions (IR) 1 and 5. This study shows the possible dimensions and location of this absorber, and how it would reduce both the peak power density and total heat load.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO027

First Beam Background Simulation Studies at IR1 for High Luminosity LHC

1074

R. Kwee-Hinzmann, S.M. Gibson
JAI, Egham, Surrey, United Kingdom
G. Bregliozzi, R. Bruce, F. Cerutti, L.S. Esposito, R. Kersevan, A. Lechner, N.V. Shetty
CERN, Geneva, Switzerland
S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom

In the High-Luminosity Large Hadron Collider (HL-LHC) Project, the LHC will be significantly upgraded to attain a peak luminosity of up to 8.5 × 10³⁴ cm^-2s^-1, thus almost an order of magnitude higher compared to the nominal machine configuration in ATLAS at IP1 and CMS at IP5. In the view of a successful machine setup as well as a successful physics programme, beam induced background studies at IP1 were performed to investigate sources of particle fluxes to the experimental area. In particular as a start of the study, two sources forming the major contributions were simulated in detail: the first one considers inelastic interactions from beam particles hitting tertiary collimators, the second one from beam interactions with residual gas-molecules in the vacuum pipe close by the experiment, referred to as beam-halo and local beam-gas, respectively. We will present these first HL-LHC background studies based on SixTrack and FLUKA simulations, highlighting the simulation setup for the design case in the HL-LHC scenario. Results of particle spectra entering the ATLAS detector region are presented for the latest study version of HL-LHC machine layout (2013).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO027

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI092

Test and Simulation Results for Quenches Induced by Fast Losses on a LHC Quadrupole

2706

C. Bracco, B. Auchmann, W. Bartmann, M. Bednarek, A. Lechner, M. Sapinski, R. Schmidt, N.V. Shetty, M. Solfaroli Camillocci, A.P. Verweij
CERN, Geneva, Switzerland

A test program for beam induced quenches was started in the LHC in 2011 in order to reduce as much as possible BLM-triggered beam dumps, without jeopardizing the safety of the superconducting magnets. A first measurement was performed to assess the quench level of a quadrupole located in the LHC injection region in case of fast (ns) losses. It consisted in dumping single bunches onto an injection protection collimator located right upstream of the quadrupole, varying the bunch intensity up to 3·10¹⁰ protons and ramping the quadrupole current up to 2200 A. No quench was recorded at that time. The test was repeated in 2013 with increased bunch intensity (6·10¹⁰ protons); a quench occurred when powering the magnet at 2500 A. The comparison between measurements during beam induced and quench heaters induced quenches is shown. Results of FLUKA simulations on energy deposition, calculations on quench behaviour using QP3 and the respective estimates of quench levels are also presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI092

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)