LSWG day Sept 2 2014 B Auchmann for the BLMTWG Collaboration of many teams OP RF BI Collimation LIBD FLUKA etc T Baer M Bednarek G Bellodi C Bracco R Bruce F Cerutti ID: 377958
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Slide1
Quench Level MDs
LSWG day, Sept. 2, 2014, B. Auchmann for the BLMTWG
Collaboration of many teams: OP, RF, BI, Collimation, LIBD, FLUKA, etc.
T. Baer, M.
Bednarek
, G.
Bellodi
, C.
Bracco
, R. Bruce, F.
Cerutti
, V.
Chetvertkova
,
B
.
Dehning
, P. P.
Granieri
, W.
Hofle
, E. B.
Holzer
, A.
Lechner
, E.
Nebot
Del Busto,
Priebe
, S.
Redaelli
, B.
Salvachua
, M.
Sapinski
, R. Schmidt, N.
Shetty
, E.
Skordis
,
M
.
Solfaroli
, D.
Valuch
, A.
Verweij
, J.
Wenninger
, D.
Wollmann
, M.
ZerlauthSlide2
Quench Test
Analysis What is the energy deposition in the coil at the moment of quench?
Particle
Shower
FCBM: loss rate
QPS: moment
of quench
Particle tracking:
spatial
distribution
BLM signals
Validation
Input
Analysis
Electro
-Thermal
Estimate (MQED)
BLM: normalized
t
ime distribution
P.
s
hower: norm.
space distribution
Quench test
QPS: moment
of quench
Subscale experiments
Quench
Level
Upper bound
or estimate
Lower bound
quench
no quench
Particle
Tracking
Settings: bump
amplitude etc.
Beam
parametermeasurements: ε, Q, etc.
BLM normalizedtime distribution
BPM signalsSlide3
Why quench tests?
To obtain binary quench/
no-quench data for realistic beam loss scenarios, e.g.,collimation (see Stefano’s talk), andsingle-turn losses on collimators
(see Jan’s talk)
.
To validate electro-thermal and particle-shower models
used to set BLM thresholds,used to define requirements for upgrades.To understand beam loss scenarios relevant for BLM thresholdSlide4
Single-Turn L
osses (LIBD)
2011 MD2: Quench tests (QT) on Q4/TCSG and Q6/TCLIB at 450 GeV.No quenches
occurred for varying collimator settings, bunch intensities, and orbit bump.
BLM
Callibration
studies performed.Documentation:CERN-ATS-Note-2011-067 MD, W. Bartmann, et al., Quench Margin at
Injection.C.
Bracco, et al., Experiments on the Margin of Beam Induced Quenches for LHC Superconducting Quadrupole Magnet in the LHC, IPAC2012.2013 End-of-Run QT Campaign:
Q6/TCLIB QT, 450 GeV bunches, variable magnet currents.
Q6 magnet was quenched.No FLUKA validation with BLM data due to saturation.
Moderate consistency. Documentation:C. Bracco, et al. Test and Simulation Results for Quenches Induced by Fast Losses on a LHC Quadrupole, IPAC 2014
.Run 2 tests:
Q4/TCSG test (see LIBD talk). Improve diagnostics by LICs?Slide5
UFO Time-Scale Losses
2010:
Wire-scanner quench test on D4 magnet
D4 (@4.5 K) quenched.
Uncertainties due to timing and loss maximum in coil ends.
2013 End-of-Run QT Campaign:
ADT quench testMQ quenched.Large uncertainty on moment of quench.Large uncertainties in electro-thermal model
.Best approximation of UFO-type losses in
1.9 K magnets.Slide6
UFO Time-Scale Losses
2013 End-of-Run QT Campaign:
ADT quench testPreparatory MDs: 2012 MD 1/2/3, 2013 testDocumentationCERN-ATS-Note-2013-017 MD, A.
Priebe
, et al., ADT fast losses
MD
M. Sapinski, et al., Generation of Controlled Losses in Milisecond Timescale with Transverse Damper in LHC, IPAC 2013.V. Chetvertkova, et al., MadX
Tracking Simulations to Determine the Beam loss Distributions for the LHC Quench Tests with ADT Excitation, IPAC 2014.
N. V. Shetty, et al., Energy Deposition and Quench Level Calculations for Millisecond and Steady-state Quench Tests of LHC Arc Quadrupoles at 4 TeV, IPAC2014.C.
Bracco, et al. Test and Simulation Results for Quenches Induced by Fast Losses on a LHC Quadrupole, IPAC 2014.M. Sapinski, et al., Beam-induced Quench Tests of LHC Magnets, IPAC 2014.PRSTAB paper to be submitted in autumn 2014.
A. Priebe, CERN-THESIS-2014-013.Run 2 tests:
Repeat ADT quench test with improvements:better instrumentation (oscilloscope),complete set of beam-parameter measurements just before the test,good understanding of ADT settings,even faster losses.In parallel we aim at improving the electro-thermal model;
see BIQ workshop, Sept. 15-16, (http://indico.cern.ch/event/BIQ2014).Slide7
UFO Time-Scale Losses
Run 2 tests continued
:Study losses induced by fast current-change in RD1.L/R1 (B. Dehning):
Based on CERN
-THESIS-2009-023, Andres Gomez
Alonso
Retreat collimators and create orbit bump in MQ. Lose pilot bunch within ~10 turns due to orbit distortion.Detailed
study needed. Slide8
Steady-State Losses
2010 Dynamic orbit bump quench tests at injection and 3.5
TeVQuenches in MQ at 450 GeV and 3.5 TeV
.
Analysis results will be used to se low-energy arc and DS thresholds.
Documentation:
A. Priebe, et al., Beam-induced Quench Test of a LHC Main Quadrupole, IPAC 2011.A. Priebe
, et al., Investigation of Quench Limits of the LHC Superconducting Magnets, IEEE Trans. On Appl. SC,
Vol 23, No 3, June 2013.A. Priebe, CERN-THESIS-2014-013.PRSTAB paper to be submitted in autumn 2014
.Collimation quench tests (see Collimation talk)No quenches occurred!2013 End-of-Run QT CampaignADT quench testMQ quenched after 20 s of
steady losses.FLUKA/BLM discrepancy.Modest (30 µm) stepin surface roughness could produce a
better fit to BLM data.No full validation of electro-thermal model.Slide9
Steady-State Losses
2013 End-of-Run QT Campaign
ADT quench test continued.Documentation:V. Chetvertkova
, et al.,
MadX
Tracking Simulations to Determine the Beam loss Distributions for the LHC Quench Tests with ADT Excitation, IPAC 2014
.N. V. Shetty, et al., Energy Deposition and Quench Level Calculations for Millisecond and Steady-state Quench Tests of LHC Arc Quadrupoles at 4 TeV, IPAC2014.
M. Sapinski, et al., Beam-induced Quench Tests of LHC Magnets, IPAC 2014.
PRSTAB paper to be submitted in autumn 2014.A. Priebe, CERN-THESIS-2014-013.Run 2 tests
: Repeat ADT quench test with improvements:complete set of beam-parameter measurements just before the test,good understanding of ADT settings,
in a different aperture or magnet.In parallel we aim at improving the electro-thermal model; see BIQ workshop, Sept. 15-16, (http://indico.cern.ch
/event/BIQ2014).Slide10
Summary
Series of successful quench tests help to
improve and validate the electro-thermal model,set BLM thresholds for Run 2.Additional tests are required tovalidate the steady-state quench levels,
Improve knowledge on UFO time-scale losses.Slide11Slide12
Wire Scanner
Installation of a wire scanner to produce losses in Q7 or further downstream.
Affected magnets at 1.9 K (in contrast to installed WS).Considerable cost (B. Dehning rough estimate 200
kCHF
).
Installation during long
stop for vacuum issues.Requires pre-study:Losses in magnet ends lead to large error margins in the analysis.See if losses can be generated in the longitudinal center of the magnet
.Could provide “UFO factory” – if needed.