Calvi, M
Floch, E
Kouzue, S
Siemko, A
Improved Quench Localization and Quench Propagation Velocity Measurements in the LHC Superconducting Dipole Magnets
IEEE Trans. Appl. Supercond.
1209-12
15
The series tests performed on the LHC superconducting magnets at cryogenic condition give a unique opportunity to understand the mechanisms responsible for the instabilities causing the so-called training quenches. The first series production tests demonstrated that the weak points in the LHC dipoles are the coil extremities in which the majority of the quenches are located. This evidence triggered the idea of improving the resolution of the measuring system to better characterize the starting region of a quench and the beginning of its propagation. The new quench antennas equipped with sets of small, 4 cm long, and sensitive pick-up coils were designed. The system is described in detail and the first measurement results are presented. It turned out that this tool is also a reliable technique for measuring the quench propagation velocity especially in the particular regions of the superconducting coils like the crossing between the straight section of the magnet and its extremity.
eng
improved quench localization;
quench propagation velocity measurements;
LHC superconducting dipole magnets;
cryogenic condition;
training quenches;
production tests;
coil extremities;
quench antennas;
sensitive pick up coils;
reliable technique;
superconducting coils;
4 cm;
2005
http://documents.cern.ch/cgi-bin/setlink?base=generic&categ=public&id=cer-002519810;
http://documents.cern.ch/cgi-bin/setlink?base=preprint&categ=cern&id=lhcproj-2005-809;
http://cds.cern.ch/record/833473/files/cer-002519810.pdf;
http://cds.cern.ch/record/833473/files/lhc-project-report-809.pdf;
Imported from Invenio.
Sanfilippo, S
Bottura, L
Calvi, M
Chohan, V
Durante, M
Hagen, P
Pugnat, P
Smirnov, N
Schnizer, P
Sammut, N
Siemko, A
Simon, F
Stafiniak, A
Todesco, Ezio
Tortschanoff, Theodor
Walckiers, L
Axis Measurements, Field Quality and Quench Performance of the First LHC Short Straight Sections
IEEE Trans. Appl. Supercond.
1098-101
15
The series testing at 1.9 K of the 360 Short Straight Sections (SSS) for the Large Hadron Collider have started at CERN in September 2003. The SSS contain the lattice quadrupoles and correction magnets in a common cryostat. The lattice quadrupoles feature two collared coils with 56 mm bore assembled in a common yoke. The coils are wound in two-layers from 15.1 mm wide NbTi cable, insulated with polyimide tape. The paper reviews the main test results performed in superfluid helium. The magnetic field and magnetic center position of the quadrupoles and associated correctors were measured with two independent systems, namely an automated scanner and a single stretched wire technique. The quench training, the field quality and the magnetic alignment measurements are presented and discussed in terms of the specifications and expected performances of these magnets in the LHC. We discuss in detail the field quality in terms of multipole errors measured at injection and nominal field and decomposed into geometric and persistent current magnetization errors. Warm/cold correlation for the geometric multipoles and the magnetic axis is also presented.
eng
field quality;
quench performance;
LHC short straight sections;
series testing;
Large Hadron Collider;
CERN;
AD 09 2003;
lattice quadrupoles;
correction magnets;
common cryostat;
NbTi cable;
superfluid helium;
magnetic field measurement;
position measurement;
automated scanner;
single stretched wire technique;
quench training;
magnetic alignment measurements;
multipole errors measurement;
magnetization errors;
warm cold correlation;
geometric multipoles;
magnetic axis measurement;
superconducting accelerator magnets;
15;
2005
http://documents.cern.ch/cgi-bin/setlink?base=generic&categ=public&id=cer-002519646;
http://documents.cern.ch/cgi-bin/setlink?base=preprint&categ=cern&id=lhcproj-2005-808;
http://cds.cern.ch/record/833205/files/cer-002519646.pdf;
http://cds.cern.ch/record/833205/files/lhc-project-report-808.pdf;
Imported from Invenio.
Pojer, M
Pugnat, P
Siemko, A
Verweij, A
Vullierme, B
Conductor-Limited Quenches of LHC Superconducting Main Dipoles
IEEE Trans. Appl. Supercond.
1554-7
15
In the framework of the series tests of superconducting magnets for the LHC, a special procedure was developed at CERN to perform conductor-limited quenches at temperatures around 4.4 K. All results obtained on pre-series and series main dipoles tested to date will be presented with their analysis. These quenches allow fine diagnostics concerning the electrical integrity of the conductors and of the splices. They also allow the determination for each magnet of the temperature margin at nominal operating conditions of the LHC at superfluid helium. The comparison between the quench current and the critical current directly measured on short samples of superconducting cables used for the winding is discussed.
eng
conductor limited quenches;
LHC superconducting main dipole;
superconducting magnet;
CERN;
dipole testing;
electrical integrity;
superfluid helium;
quench current;
critical current;
superconducting cable;
Large Hadron Collider;
2005
http://documents.cern.ch/cgi-bin/setlink?base=generic&categ=public&id=cer-002519643;
http://documents.cern.ch/cgi-bin/setlink?base=preprint&categ=cern&id=lhcproj-2005-807;
http://cds.cern.ch/record/833204/files/cer-002519643.pdf;
http://cds.cern.ch/record/833204/files/lhc-project-report-807.pdf;
Imported from Invenio.
Ostojic, R
Catalan-Lasheras, N
Kirby, G A
Pérez, J C
Prin, H
Venturini-Delsolaro, W
Status of Production of the Superconducting Matching Quadrupoles for the LHC Insertions
IEEE Trans. Appl. Supercond.
1094-7
15
Special individually powered superconducting quadrupoles are required for the LHC insertions. These units comprise quadrupole magnets of the MQM and MQY types and range in length from 5.4 m to 11.4 m. In total, 82 insertion quadrupoles will be assembled at CERN. In this paper we present the advance in construction of the magnets and report on the performance of the first series built units, including power tests and alignment of the cold masses.
eng
superconducting matching quadrupoles;
LHC insertions;
quadrupole magnets;
MQM;
MQY;
insertion quadrupoles;
CERN;
power tests;
cold masses alignment;
5;
2005
http://documents.cern.ch/cgi-bin/setlink?base=generic&categ=public&id=cer-002519622;
http://documents.cern.ch/cgi-bin/setlink?base=preprint&categ=cern&id=lhcproj-2005-806;
http://cds.cern.ch/record/833203/files/cer-002519622.pdf;
http://cds.cern.ch/record/833203/files/lhc-project-report-806.pdf;
Imported from Invenio.
de Rijk, G
Bajko, M
Cornelis, M
Durante, M
Fessia, P
Miles, J
Modena, M
Molinari, G
Rinn, J
Savary, F
Schirm, K
Simon, F
Tommasini, D
Tortschanoff, Theodor
Vlogaert, J
Status Report on the LHC Main Magnet Production
IEEE Trans. Appl. Supercond.
1078-83
15
The LHC ring will contain 1232 main dipole and 382 main quadrupole twin aperture magnets. All main magnets are superconducting and employ NbTi/Cu Rutherford type cables operated at 1.9 K. The dipole production has reached the equivalent of almost three octants of cold masses and nearly four octants of collared coils. The quadrupole production has reached 75 cold masses and over 150 bare magnets. The ramping up of large scale magnet production has posed several challenges which will be discussed, like: the coil size uniformity, coil pre-stress control, cold mass welding technique and the geometrical shape issues. The magnetic measurement results at warm will be presented together with their usage for the quality control in the production. The common features and differences of the three dipole producers will be discussed. Finally the latest version of the production schedule will be presented.
eng
main magnet production;
LHC ring;
quadrupole double aperture magnets;
superconducting magnets;
Rutherford type cables;
dipole production;
quadrupole production;
coil size uniformity;
coil pre stress control;
cold mass welding;
geometrical shape issues;
magnetic measurement;
quality control;
production schedule;
production control;
superconducting accelerator magnets;
NbTi Cu;
2005
http://documents.cern.ch/cgi-bin/setlink?base=generic&categ=public&id=cer-002519605;
http://documents.cern.ch/cgi-bin/setlink?base=preprint&categ=cern&id=lhcproj-2005-805;
http://cds.cern.ch/record/833202/files/cer-002519605.pdf;
http://cds.cern.ch/record/833202/files/lhc-project-report-805.pdf;
Imported from Invenio.
Bellesia, B
Bottura, L
Granata, V
Le Naour, S
Oberli, L
Sanfilippo, S
Santoni, C
Scandale, Walter
Schwerg, N
Todesco, Ezio
Völlinger, C
Trends in Cable Magnetization and Persistent Currents during the Production of the Main Dipoles of the Large Hadron Collider
IEEE Trans. Appl. Supercond.
1213-16
15
The production of more than 60% of superconducting cables for the main dipoles of the Large Hadron Collider has been completed. The results of the measurements of cable magnetization and the dependence on the manufacturers are presented. The strand magnetization produces field errors that have been measured in a large number of dipoles (approximately 100 to date) tested in cold conditions. We examine here the correlation between the available magnetic measurements and the large database of cable magnetization. The analysis is based on models documented elsewhere in the literature. Finally, a forecast of the persistent current effects to be expected in the LHC main dipoles is presented, and the more critical parameters for beam dynamics are singled out.
eng
cable magnetization;
persistent currents;
main dipoles production;
Large Hadron Collider;
superconducting cables;
strand magnetization;
beam dynamics;
magnetic field measurement;
superconducting accelerator magnets;
2005
http://documents.cern.ch/cgi-bin/setlink?base=generic&categ=public&id=cer-002519595;
http://documents.cern.ch/cgi-bin/setlink?base=preprint&categ=cern&id=lhcproj-2005-804;
http://cds.cern.ch/record/833201/files/cer-002519595.pdf;
http://cds.cern.ch/record/833201/files/lhc-project-report-804.pdf;
Imported from Invenio.
Devred, Arnaud
Gourlay, S A
Yamamoto, A
Future Accelerator Magnet Needs
IEEE Trans. Appl. Supercond.
1192-9
15
Superconducting magnet technology is continually evolving in order to meet the demanding needs of new accelerators and to provide necessary upgrades for existing machines. A variety of designs are now under development, including high fields and gradients, rapid cycling and novel coil configurations. This paper presents a summary of R&D programs in the EU, Japan and the USA. A performance comparison between NbTi and Nb$_{3}$Sn along with fabrication and cost issues are also discussed.
eng
accelerator magnet;
superconducting magnet;
R D programs;
EU;
Japan;
USA;
NbTi;
Nb3Sn;
2005
http://documents.cern.ch/cgi-bin/setlink?base=generic&categ=public&id=cer-002519297;
http://documents.cern.ch/cgi-bin/setlink?base=preprint&categ=cern&id=at-2005-006;
http://documents.cern.ch/archive/electronic/other/uploader/CARE/Conf/care-conf-04-037.pdf;
http://cds.cern.ch/record/832905/files/at-2005-006.pdf;
http://cds.cern.ch/record/832905/files/care-conf-04-037.pdf;
http://cds.cern.ch/record/832905/files/cer-002519297.pdf;
Imported from Invenio.
Bottura, L
Satiramatekul, T
Bouillault, F
Devred, Arnaud
Analytical & Numerical Modelings of Elliptical Superconducting Filament Magnetization
This paper deals with the two-dimensional computation of magnetization in an elliptic superconducting filament by using numerical and analytical methods. The numerical results are obtained from the finite element method and by using Bean's model. This model is well adapted for Low Tc superconductor studies. We observe the effect of the axis ratio and of the field angle to the magnetic moment per unit length at saturation, and also to the cycle of magnetization. Moreover, the current density and the distribution of the electromagnetic fields in the superconducting filament are also studied.
eng
2005
http://documents.cern.ch/cgi-bin/setlink?base=preprint&categ=cern&id=at-2005-005;
http://cds.cern.ch/record/832904/files/at-2005-005.pdf;
Imported from Invenio.
Bottura, L
Bruzzone, P
Fischer, E
Kauschke, M
Moritz, G
Vysotsky, V S
Sytnikov, V E
Wilson, M
A Cable-in-Conduit Superconductor for Pulsed Accelerator Magnets
Superconducting magnets for future accelerators such as the SIS-100 ring of the International Accelerator Facility at GSI-Darmstadt, or a superconducting injector at the LHC, require that the magnetic field is pulsed with high repetition rate and high reliability over periods of several years. As an example the SIS-100 at the IAF is planned to be operated up to 2 T at 4 T/s for more than 100 millions cycles. Achieving these objectives requires that the superconductor has an excellent mechanical stability as well as a sufficient energy margin to tolerate foreseen and unforeseen energy inputs. In addition the cryogenic loss must be controlled at low levels, while the field errors due to coupling currents must be compatible with the beam dynamics requirements. In this paper we describe a cable-in-conduit design that is suitable for the challenging operating conditions described above, we give the expected performances and report on the on-going manufacturing demonstration and planned supporting tests.
eng
2005
http://documents.cern.ch/cgi-bin/setlink?base=preprint&categ=cern&id=at-2005-004;
http://cds.cern.ch/record/832903/files/at-2005-004.pdf;
Imported from Invenio.
Bottura, L
Ambrosio, G
Bauer, P
Haverkamp, M
Pieloni, T
Sanfilippo, S
Velev, G
A Scaling Law for the Snapback in Superconducting Accelerator Magnets
IEEE Trans. Appl. Supercond.
1217-20
15
The decay of the sextupole component in the bending dipoles during injection and the subsequent snapback at the start of beam acceleration are issues of common concern for all superconducting colliders built or in construction. Recent studies performed on LHC and Tevatron dipole magnets revealed many similarities in the snapback characteristics. Some are expected, e.g. the effect of operational history. One particular similarity, however, is striking and is the subject of this paper. It appears that there is a simple linear relation between the amount of sextupole drift during the decay and the magnet current (or field) change during the ramp required to resolve the snapback. It is surprising that the linear correlation between snapback amplitude and snapback field holds very well for all magnets of the same family (e.g. Tevatron or LHC dipoles). In this paper we present the data collected to date and discuss a simple theory that explains the scaling found.
eng
superconducting accelerator magnets;
sextupole component;
bending dipoles;
beam acceleration;
superconducting colliders;
LHC;
Tevatron dipole magnets;
snapback characteristics;
sextupole drift;
magnet current change;
current distribution;
magnetization reversal;
2005
http://documents.cern.ch/cgi-bin/setlink?base=generic&categ=public&id=cer-002519293;
http://documents.cern.ch/cgi-bin/setlink?base=preprint&categ=cern&id=at-2005-003;
http://cds.cern.ch/record/832902/files/at-2005-003.pdf;
http://cds.cern.ch/record/832902/files/cer-002519293.pdf;
Imported from Invenio.
Devred, Arnaud
Baudouy, B
Baynham, D Elwyn
Boutboul, T
Canfer, S
Chorowski, M
den Ouden, A
Fabbricatore, P
Farinon, S
Fessia, P
Fydrych, J
Félice, H
Greco, Michela
Greenhalgh, J
Leroy, D
Loveridge, P W
Michel, F
Oberli, L R
Pedrini, D
Polinski, J
Previtali, V
Quettier, L
Rifflet, J M
Rochford, J
Rondeaux, F
Sanz, S
Sgobba, Stefano
Sorbi, M
Toral-Fernandez, F
Van Weelderen, R
Vincent-Viry, O
Volpini, G
Védrine, P
Status of the Next European Dipole (NED) Activity of the Collaborated Accelerator Research in Europe (CARE) Project
IEEE Trans. Appl. Supercond.
1106-12
15
Plans for LHC upgrade and for the final focalization of linear colliders call for large aperture and/or high-performance dipole and quadrupole magnets that may be beyond the reach of conventional NbTi magnet technology. The Next European Dipole (NED) activity was launched on January 1st, 2004 to promote the development of high-performance, Nb$_{3}$Sn wires in collaboration with European industry (aiming at a non-copper critical current density of 1500Â A/mm2 at 4.2 K and 15 T) and to assess the suitability of Nb$_{3}$Sn technology to the next generation of accelerator magnets (aiming at an aperture of 88 mm and a conductor peak field of 15 T). It is integrated within the Collaborated Accelerator Research in Europe (CARE) project, involves seven collaborators, and is partly funded by the European Union. We present here an overview of the NED activity and we report on the status of the various work packages it encompasses.
eng
AD 01 01 2004;
CARE Project;
Collaborated Accelerator Research in Europe;
European Union;
LHC upgrade;
Nb2Sn;
NbTi magnet technology;
Next European Dipole activity;
accelerator magnets;
high magnetic field;
high performance wires;
large aperture high performance dipole;
linear colliders;
noncopper critical current density;
quadrupole magnets;
2005
http://documents.cern.ch/cgi-bin/setlink?base=preprint&categ=cern&id=at-2005-002;
http://documents.cern.ch/archive/electronic/other/uploader/CARE/Conf/care-conf-04-020.pdf;
http://cds.cern.ch/record/832900/files/at-2005-002.pdf;
http://cds.cern.ch/record/832900/files/care-conf-04-020.pdf;
Imported from Invenio.
Trillaud, F
Ayela, F
Devred, Arnaud
Fratini, M
Leboeuf, D
Tixador, P
Quench Propagation Ignition using Single-Mode Diode Laser
The stability of NbTi-based multifilamentary composite wires subjected to local heat disturbances of short durations is studied in pool boiling helium conditions. A new type of heater is being developed to characterize the superconducting to normal state transition. It relies on a single-mode Diode Laser with an optical fiber illuminating the wire surface. This first paper focuses mainly on the feasibility of this new heater technology and eventually discusses the difficulties related to it. A small overview of Diode Lasers and optical fibers revolving around our application is given. Then, we describe the experimental setup, and present some recorded voltage traces of transition and recovery processes. In addition, we present also some energy and Normal Zone Propagation Velocity data and we outline ameliorations that will be done to the system.
eng
2005
http://documents.cern.ch/cgi-bin/setlink?base=preprint&categ=cern&id=at-2005-001;
http://cds.cern.ch/record/832898/files/at-2005-001.pdf;
Imported from Invenio.