Louis Walckiers - Academia.edu (original) (raw)

Papers by Louis Walckiers

The LHC low-E triplets require a short and strong dipole corrector. The MCBX is a superconducting... more The LHC low-E triplets require a short and strong dipole corrector. The MCBX is a superconducting single aperture magnet, which features a horizontal dipole nested inside a vertical dipole. The cold tests of the first prototype, which was designed by CERN and built by Danfysik A/S, have been carried out at CERN. This paper presents the results of the magnet training and quench propagation studies at 4.3 K and 1.9 K. The magnetic measurements carried out at constant field and in ramped conditions are compared to the expected figures from the calculations.

Thekernel design oftheFlexible Framework for Magnetic Measurements (FFMM),underdevelopment atthe ... more Thekernel design oftheFlexible Framework for Magnetic Measurements (FFMM),underdevelopment atthe European Organization forNuclear Research (CERN), isdescribed. Thedesignaimsatsatisfying thecritical scenario ofshort-term requirement variability forthesmall batches ofmagnets after the commissioning fortheLargeHadronCollider (LHC).The experimental test results ofsoftware flexibility andscalability are illustratedfor acasestudy ofsuperconducting magnets inwarmand coldon-field conditions.

A new type of radiation detector, a p-type modified electrode germanium diode, is presented. It i... more A new type of radiation detector, a p-type modified electrode germanium diode, is presented. It is shown that the prototype displays, for the first time, a combination of features (mass, energy threshold and background expectation) required for a measurement of coherent neutrino-nucleus scattering in a nuclear reactor experiment. First results are presented from its calibration using sub-kiloelectronvolt nuclear recoils similar to those expected from reactor antineutrinos or light WIMPs (weakly interacting massive particles) beyond the reach of present detectors. The device hybridizes the mass and energy resolution of a conventional HPGe coaxial gamma spectrometer with the low electronic noise and threshold of a small x-ray semiconductor detector, also displaying an intrinsic ability to distinguish multiple-site from single-site particle interactions. The present performance of the prototype and possible further improvements are discussed, as well as other applications for this new type of device in neutrino and astroparticle physics (double-beta decay, neutrino magnetic moment and novel WIMP searches).

AIP Conference Proceedings, 2002

The LHC development program relies on cryogenic tests of prototype and model magnets. This vigoro... more The LHC development program relies on cryogenic tests of prototype and model magnets. This vigorous program is pursued in a dedicated test facility based on several vertical cryostats working at superfluid helium temperatures. The performance of the facility is detailed. Goals and test equipment for currently performed studies are reviewed: quench analysis and magnet protection studies, measurement of the field quality, test of ancillary electrical equipment like diodes and busbars. The paper covers the equipment available for tests of prototypes and some special series of LHC magnets to come.

A number of twin aperture, 10 m long, model dipole magnets for the LHC Project have been built an... more A number of twin aperture, 10 m long, model dipole magnets for the LHC Project have been built and tested. With regard to the models of the first generation, the inner coil diameter and the intra-beam distance were increased from 50 to 56 mm and from 180 to about 194 mm, respectively. Also with regard to the previous models, a 5-block coil cross-section was chosen and the width of the Rutherford cable was reduced from 17 mm to 15 mm. The coils were manufactured and collared in Industry, the assembly of their magnetic circuit and cold mass were carried out at CERN. The individual design and manufacturing features of each of these magnets are described and the results of warm and cold magnetic measurement are presented and discussed.

Within the LHC magnet research and development programme, a series of single aperture 1m long mod... more Within the LHC magnet research and development programme, a series of single aperture 1m long models of second generation are presently being built and tested at CERN. The main features of these magnets are: five-block, two layer coils wound from 15mm wide graded NbTi cables, enlarged 56mm aperture and all-polyimide insulation. This paper reviews the power test data of magnets

The superconducting twin aperture main dipole magnets of the LHC accelerator are equipped with pa... more The superconducting twin aperture main dipole magnets of the LHC accelerator are equipped with pairs of sextupole and decapole correctors at their ends. Similarly, octupole correctors are aligned at t he end of the main quadrupole magnets. Dedicated stations have been built for tests of these correctors at room temperature as well as superfluid helium temperature. Measurements of the training behav iour and of the magnetic field quality are routinely performed. The search for the magnetic axis and the transfer of its position to fiducials are performed at room temperature. A description and the performances obtained with these two benches are also presented.

The axion, an as yet hypothetical particle predicted from the solution of the strong CP problem, ... more The axion, an as yet hypothetical particle predicted from the solution of the strong CP problem, constitutes a prime candidate for the galactic dark matter and also arises in supersymmetry and superstring theories. If existing, axions should be copiously produced in stellar interiors and there are theoretical expectations for a low-energy axion emission spectrum peaked around a mean energy of

Journal of Physics: Conference Series, 2013

The International Axion Observatory (IAXO) is a new generation axion helioscope aiming at a sensi... more The International Axion Observatory (IAXO) is a new generation axion helioscope aiming at a sensitivity to the axion-photon coupling of gaγ few×10 −12 GeV −1 , i.e. 1-1.5 orders of magnitude beyond the one achieved by CAST, currently the most sensitive axion helioscope. The main elements of IAXO are an increased magnetic field volume together with extensive use of x-ray focusing optics and low background detectors, innovations already successfully tested in CAST. Additional physics cases of IAXO could include the detection of electron-coupled axions invoked to explain the white dwarf cooling, relic axions, and a large variety of more generic axion-like particles (ALPs) and other novel excitations at the low-energy frontier of elementary particle physics.

Journal of Cosmology and Astroparticle Physics, 2007

IEEE Transactions on Nuclear Science, 1979

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1999

The 8.4 T, 10 m long transverse magnetic field of a twin aperture LHC bending magnet can be utili... more The 8.4 T, 10 m long transverse magnetic field of a twin aperture LHC bending magnet can be utilized as a macroscopic coherent solar axion-to-photon converter. Numerical calculations show that the integrated time of alignment with the Sun would be 33 days/yr with the magnet on a tracking table capable of 5°intheverticaldirectionand5°in the vertical direction and 5°intheverticaldirectionand40°in the horizontal direction. The existing lower bound on the axion-to-photon coupling constant can be improved by a factor between 30 and 100 in 3 yr, i.e., g :9;10\ GeV\ for axion masses : 1 eV. This value falls within the existing open axion mass window. The same setup can simultaneously search for low-and high-energy celestial axions, or axion-like particles, scanning the sky as the Earth rotates and orbits the Sun.

IEEE Transactions on Appiled Superconductivity, 2000

Abslruct-Wc descriljc herc ii tiew hlrmoiiic coil system tor thc Rcld mcnsurcmctlt of the supcrcr... more Abslruct-Wc descriljc herc ii tiew hlrmoiiic coil system tor thc Rcld mcnsurcmctlt of the supcrcrintliicliti~, twill ;tpertrirc 1 .HC rlipriIes and thc assticintcd ctrrrcctor mngiiets. ncsirlus ficld mcamrmicnts thc syskni c m bc used as itn antcnna to Incnlizc tlic iluench .clrigin. 'I'tiu rriiiiii component is R 16 111 lonf rotating sliaft, NI& up of 13 ceramic segincrits, euch cnrrying two tangcriti;il coils plus B central rarli;il coil, dl working in ~iiiri~llel. Thc segments arc conncctcd witb flcxible 'Vi-allfly ticllows, iillowing thc picccwisu strai~lit shaft to Collow the curviilurc of tlic dipole whilc mainteinitig b i~h torsirmnl rigidity. At each iotcrconncctiun Uic structure is supported by rnllcrs id liilll bearings, ncccssnry ftir the axial iiiovcnicnt rrw irat;ill;irinti wnrl for the rotation of the coil during mc:isiirrnic~it. 'Two siicli shafts are simdtancously driven by a twill-rotating unit, I I i w incwsuring birth spcrturcs nf ii diprile i t tlic wilinc lime. This ;trrsngcment allows very xhrirt tnursurcnieiit iinlcs (lypically 10 s) ; i i d is essential to perform cold magnetic iiicasiireitienls of all tlipolcs. Tlia coil siirfwc anrl dirwtion iire cnlibriitccl using n rcfercnce dip111~. In this papcr we rlcscribc tlic twin rntating coil system ti1111 its calitiration facility, unrl we givc the typicel rcsnlution and accuracy ticliieved with t11c first comnlissioncd unit, fine-tuning of thc rclalcd sdrwarc tools. KEliERENCES H Meinkc. "Mctliud~ for prodiiclinn nitiuiireinciits of sulwcoridiicting magnets", liitcmnl Hopnn DFSY HERA 90-06, April IW. P. Wantlercr, "Mngnct riiasiircments for scrics pmtliiclion", E R N Report WOS, pp. 273-2116.1L998. M.I. Grecn, "Pclimiim-y study of an intcgml hiimionic nnrilysis nlilgnctic field inc~~~~ircinctit systcin for long SSC I~itign'cls, P m. nf I991 Pan. Acc. Cont. Srin FRincisco, 199 I. J. Billnn, J. Bucklcy. it. %ban. P. Sicvcn. L. W~lckic~s;, "Dsign rind t a t uf thc benches for thc nqirctic tiicmirciwnt olihe LHC Dipoles", u E f i S. Bidon, J. Billan. E Fischcr. C. Saw7 "Ncw tcchiiqirc of hbi.icnrion <if search coil for mugnnctic Held mcasuirmcnt Ihy linririoriic anulysis", CERN Inttmirl Note AT-MA 95-1 17, 1'195. L. Wnlckicn. ct. al., 'Towards scriu Intirisiireinents of ilic LHC sup"liicling dipole mrignets", Pm. of 1997 t'nrl. Acc. Cod. Vnncoiivcr, pp. 3377-3373. 1907. L Bottiim ct al., "A mole for w m i niqnctic and oplical ~r~easirimieiils of LHC (Iipolu". If?' Inlcmntiund Cunfmncc on Magiict Tccliiiolugy (MTI 6). Puntc Vutlrr! Baich, FL, USA, 26 Sept.-2 Okl, 1999. A. Siemko et d, 'Qiieiich locntion iii the siipercontluctitig lriudcl mgncts for the LHC by mcans nf pickup coils", UXi? Trtin. AppL Sup, vu1 5(2) pp. 1028-1031, 1WS. ?LwN. Mug.+ VOI. 30, pp. 26V-266 I, I W.

At CERN, the control of five of the accelerators in the injector chain (i.e. PS, PS Booster, SPS,... more At CERN, the control of five of the accelerators in the injector chain (i.e. PS, PS Booster, SPS, LEIR and AD) is based upon real-time magnetic measurements in a reference magnet. These systems ("B-trains") include usually a field marker to signal the achievement of a given field value, complemented by one or more pick-up coils to integrate flux changes. Recently, some issues have been raised concerning long-term reliability and possible performance improvements, in terms of both resolution and operational flexibility, for these systems. This paper reports the results of R activities launched to address these concerns, namely: the development of a novel ferrite gradient compensator to enable dynamic NMR field marking in the PS' combined function magnets; and the preliminary design of a standardized electronic acquisition and conditioning system aimed at enabling the requested improvements and at facilitating rapid maintenance interventions.

In this work we present the results of the measurement campaign of the main bending magnets of th... more In this work we present the results of the measurement campaign of the main bending magnets of the SESAME storage ring, which were fully characterized at ALBACELLS magnetic measurements facility. A total of 17 combined function dipoles – 16 series magnets plus a preseries one – has been tested and magnetically measured. This campaign has been performed using a dedicated Hall probe bench. The main measurements included the transfer function at the center of the magnet and field maps of the three components of the field in a plane around the nominal trajectory of the electron beam, at two different operating currents. In this paper we describe the experimental setup and procedures, before reporting the main results, including statistics of magnet-to-magnet reproducibility and integrated field quality. Finally, we show how the measured data can be exploited for an optimal 3D alignment of the dipoles in the machine.

A flexible and easy-to-implement management structure for large amount of measurement and test da... more A flexible and easy-to-implement management structure for large amount of measurement and test data is proposed. Its main aim is to cope with industrial and research environment where the difficulty to make measurements requires to minimise the number of measurements campaigns and maximize the use of the data taken in these campaigns. This goal is achieved by providing well-defined structures for raw data storage and Data Base storage and clear separation between the analysis processes. A case study on test data of superconducting magnets for the Large Hadron Collider at the European Organization for Nuclear Research (CERN) is illustrated for managing present and future magnetic measurements requests.

The CAST experiment at CERN is the only running solar axion telescope. The first results obtained... more The CAST experiment at CERN is the only running solar axion telescope. The first results obtained so far with CAST-PHASE I is presented, which compete with the best astrophysically derived limits of the axion-tophoton coupling. The ongoing PHASE II of the experiment as well as the scheduled upgrades, which improve the axion discovery potential of CAST, are discussed.

Nuclear Physics B - Proceedings Supplements, 2005

Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by th... more Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by the Primakoff process. In a laboratory magnetic field (''axion helioscope''), they would be transformed into xrays with energies of a few keV. Using a decommissioned Large Hadron Collider test magnet, the CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axionphoton coupling g a < 1:16 10 ÿ10 GeV ÿ1 at 95% C.L. for m a & 0:02 eV. This limit, assumption-free, is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment over a broad range of axion masses.

Nuclear Physics B - Proceedings Supplements, 2003

The LHC low-E triplets require a short and strong dipole corrector. The MCBX is a superconducting... more The LHC low-E triplets require a short and strong dipole corrector. The MCBX is a superconducting single aperture magnet, which features a horizontal dipole nested inside a vertical dipole. The cold tests of the first prototype, which was designed by CERN and built by Danfysik A/S, have been carried out at CERN. This paper presents the results of the magnet training and quench propagation studies at 4.3 K and 1.9 K. The magnetic measurements carried out at constant field and in ramped conditions are compared to the expected figures from the calculations.

Thekernel design oftheFlexible Framework for Magnetic Measurements (FFMM),underdevelopment atthe ... more Thekernel design oftheFlexible Framework for Magnetic Measurements (FFMM),underdevelopment atthe European Organization forNuclear Research (CERN), isdescribed. Thedesignaimsatsatisfying thecritical scenario ofshort-term requirement variability forthesmall batches ofmagnets after the commissioning fortheLargeHadronCollider (LHC).The experimental test results ofsoftware flexibility andscalability are illustratedfor acasestudy ofsuperconducting magnets inwarmand coldon-field conditions.

A new type of radiation detector, a p-type modified electrode germanium diode, is presented. It i... more A new type of radiation detector, a p-type modified electrode germanium diode, is presented. It is shown that the prototype displays, for the first time, a combination of features (mass, energy threshold and background expectation) required for a measurement of coherent neutrino-nucleus scattering in a nuclear reactor experiment. First results are presented from its calibration using sub-kiloelectronvolt nuclear recoils similar to those expected from reactor antineutrinos or light WIMPs (weakly interacting massive particles) beyond the reach of present detectors. The device hybridizes the mass and energy resolution of a conventional HPGe coaxial gamma spectrometer with the low electronic noise and threshold of a small x-ray semiconductor detector, also displaying an intrinsic ability to distinguish multiple-site from single-site particle interactions. The present performance of the prototype and possible further improvements are discussed, as well as other applications for this new type of device in neutrino and astroparticle physics (double-beta decay, neutrino magnetic moment and novel WIMP searches).

AIP Conference Proceedings, 2002

The LHC development program relies on cryogenic tests of prototype and model magnets. This vigoro... more The LHC development program relies on cryogenic tests of prototype and model magnets. This vigorous program is pursued in a dedicated test facility based on several vertical cryostats working at superfluid helium temperatures. The performance of the facility is detailed. Goals and test equipment for currently performed studies are reviewed: quench analysis and magnet protection studies, measurement of the field quality, test of ancillary electrical equipment like diodes and busbars. The paper covers the equipment available for tests of prototypes and some special series of LHC magnets to come.

A number of twin aperture, 10 m long, model dipole magnets for the LHC Project have been built an... more A number of twin aperture, 10 m long, model dipole magnets for the LHC Project have been built and tested. With regard to the models of the first generation, the inner coil diameter and the intra-beam distance were increased from 50 to 56 mm and from 180 to about 194 mm, respectively. Also with regard to the previous models, a 5-block coil cross-section was chosen and the width of the Rutherford cable was reduced from 17 mm to 15 mm. The coils were manufactured and collared in Industry, the assembly of their magnetic circuit and cold mass were carried out at CERN. The individual design and manufacturing features of each of these magnets are described and the results of warm and cold magnetic measurement are presented and discussed.

Within the LHC magnet research and development programme, a series of single aperture 1m long mod... more Within the LHC magnet research and development programme, a series of single aperture 1m long models of second generation are presently being built and tested at CERN. The main features of these magnets are: five-block, two layer coils wound from 15mm wide graded NbTi cables, enlarged 56mm aperture and all-polyimide insulation. This paper reviews the power test data of magnets

The superconducting twin aperture main dipole magnets of the LHC accelerator are equipped with pa... more The superconducting twin aperture main dipole magnets of the LHC accelerator are equipped with pairs of sextupole and decapole correctors at their ends. Similarly, octupole correctors are aligned at t he end of the main quadrupole magnets. Dedicated stations have been built for tests of these correctors at room temperature as well as superfluid helium temperature. Measurements of the training behav iour and of the magnetic field quality are routinely performed. The search for the magnetic axis and the transfer of its position to fiducials are performed at room temperature. A description and the performances obtained with these two benches are also presented.

The axion, an as yet hypothetical particle predicted from the solution of the strong CP problem, ... more The axion, an as yet hypothetical particle predicted from the solution of the strong CP problem, constitutes a prime candidate for the galactic dark matter and also arises in supersymmetry and superstring theories. If existing, axions should be copiously produced in stellar interiors and there are theoretical expectations for a low-energy axion emission spectrum peaked around a mean energy of

Journal of Physics: Conference Series, 2013

The International Axion Observatory (IAXO) is a new generation axion helioscope aiming at a sensi... more The International Axion Observatory (IAXO) is a new generation axion helioscope aiming at a sensitivity to the axion-photon coupling of gaγ few×10 −12 GeV −1 , i.e. 1-1.5 orders of magnitude beyond the one achieved by CAST, currently the most sensitive axion helioscope. The main elements of IAXO are an increased magnetic field volume together with extensive use of x-ray focusing optics and low background detectors, innovations already successfully tested in CAST. Additional physics cases of IAXO could include the detection of electron-coupled axions invoked to explain the white dwarf cooling, relic axions, and a large variety of more generic axion-like particles (ALPs) and other novel excitations at the low-energy frontier of elementary particle physics.

Journal of Cosmology and Astroparticle Physics, 2007

IEEE Transactions on Nuclear Science, 1979

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1999

The 8.4 T, 10 m long transverse magnetic field of a twin aperture LHC bending magnet can be utili... more The 8.4 T, 10 m long transverse magnetic field of a twin aperture LHC bending magnet can be utilized as a macroscopic coherent solar axion-to-photon converter. Numerical calculations show that the integrated time of alignment with the Sun would be 33 days/yr with the magnet on a tracking table capable of 5°intheverticaldirectionand5°in the vertical direction and 5°intheverticaldirectionand40°in the horizontal direction. The existing lower bound on the axion-to-photon coupling constant can be improved by a factor between 30 and 100 in 3 yr, i.e., g :9;10\ GeV\ for axion masses : 1 eV. This value falls within the existing open axion mass window. The same setup can simultaneously search for low-and high-energy celestial axions, or axion-like particles, scanning the sky as the Earth rotates and orbits the Sun.

IEEE Transactions on Appiled Superconductivity, 2000

Abslruct-Wc descriljc herc ii tiew hlrmoiiic coil system tor thc Rcld mcnsurcmctlt of the supcrcr... more Abslruct-Wc descriljc herc ii tiew hlrmoiiic coil system tor thc Rcld mcnsurcmctlt of the supcrcrintliicliti~, twill ;tpertrirc 1 .HC rlipriIes and thc assticintcd ctrrrcctor mngiiets. ncsirlus ficld mcamrmicnts thc syskni c m bc used as itn antcnna to Incnlizc tlic iluench .clrigin. 'I'tiu rriiiiii component is R 16 111 lonf rotating sliaft, NI& up of 13 ceramic segincrits, euch cnrrying two tangcriti;il coils plus B central rarli;il coil, dl working in ~iiiri~llel. Thc segments arc conncctcd witb flcxible 'Vi-allfly ticllows, iillowing thc picccwisu strai~lit shaft to Collow the curviilurc of tlic dipole whilc mainteinitig b i~h torsirmnl rigidity. At each iotcrconncctiun Uic structure is supported by rnllcrs id liilll bearings, ncccssnry ftir the axial iiiovcnicnt rrw irat;ill;irinti wnrl for the rotation of the coil during mc:isiirrnic~it. 'Two siicli shafts are simdtancously driven by a twill-rotating unit, I I i w incwsuring birth spcrturcs nf ii diprile i t tlic wilinc lime. This ;trrsngcment allows very xhrirt tnursurcnieiit iinlcs (lypically 10 s) ; i i d is essential to perform cold magnetic iiicasiireitienls of all tlipolcs. Tlia coil siirfwc anrl dirwtion iire cnlibriitccl using n rcfercnce dip111~. In this papcr we rlcscribc tlic twin rntating coil system ti1111 its calitiration facility, unrl we givc the typicel rcsnlution and accuracy ticliieved with t11c first comnlissioncd unit, fine-tuning of thc rclalcd sdrwarc tools. KEliERENCES H Meinkc. "Mctliud~ for prodiiclinn nitiuiireinciits of sulwcoridiicting magnets", liitcmnl Hopnn DFSY HERA 90-06, April IW. P. Wantlercr, "Mngnct riiasiircments for scrics pmtliiclion", E R N Report WOS, pp. 273-2116.1L998. M.I. Grecn, "Pclimiim-y study of an intcgml hiimionic nnrilysis nlilgnctic field inc~~~~ircinctit systcin for long SSC I~itign'cls, P m. nf I991 Pan. Acc. Cont. Srin FRincisco, 199 I. J. Billnn, J. Bucklcy. it. %ban. P. Sicvcn. L. W~lckic~s;, "Dsign rind t a t uf thc benches for thc nqirctic tiicmirciwnt olihe LHC Dipoles", u E f i S. Bidon, J. Billan. E Fischcr. C. Saw7 "Ncw tcchiiqirc of hbi.icnrion <if search coil for mugnnctic Held mcasuirmcnt Ihy linririoriic anulysis", CERN Inttmirl Note AT-MA 95-1 17, 1'195. L. Wnlckicn. ct. al., 'Towards scriu Intirisiireinents of ilic LHC sup"liicling dipole mrignets", Pm. of 1997 t'nrl. Acc. Cod. Vnncoiivcr, pp. 3377-3373. 1907. L Bottiim ct al., "A mole for w m i niqnctic and oplical ~r~easirimieiils of LHC (Iipolu". If?' Inlcmntiund Cunfmncc on Magiict Tccliiiolugy (MTI 6). Puntc Vutlrr! Baich, FL, USA, 26 Sept.-2 Okl, 1999. A. Siemko et d, 'Qiieiich locntion iii the siipercontluctitig lriudcl mgncts for the LHC by mcans nf pickup coils", UXi? Trtin. AppL Sup, vu1 5(2) pp. 1028-1031, 1WS. ?LwN. Mug.+ VOI. 30, pp. 26V-266 I, I W.

At CERN, the control of five of the accelerators in the injector chain (i.e. PS, PS Booster, SPS,... more At CERN, the control of five of the accelerators in the injector chain (i.e. PS, PS Booster, SPS, LEIR and AD) is based upon real-time magnetic measurements in a reference magnet. These systems ("B-trains") include usually a field marker to signal the achievement of a given field value, complemented by one or more pick-up coils to integrate flux changes. Recently, some issues have been raised concerning long-term reliability and possible performance improvements, in terms of both resolution and operational flexibility, for these systems. This paper reports the results of R activities launched to address these concerns, namely: the development of a novel ferrite gradient compensator to enable dynamic NMR field marking in the PS' combined function magnets; and the preliminary design of a standardized electronic acquisition and conditioning system aimed at enabling the requested improvements and at facilitating rapid maintenance interventions.

In this work we present the results of the measurement campaign of the main bending magnets of th... more In this work we present the results of the measurement campaign of the main bending magnets of the SESAME storage ring, which were fully characterized at ALBACELLS magnetic measurements facility. A total of 17 combined function dipoles – 16 series magnets plus a preseries one – has been tested and magnetically measured. This campaign has been performed using a dedicated Hall probe bench. The main measurements included the transfer function at the center of the magnet and field maps of the three components of the field in a plane around the nominal trajectory of the electron beam, at two different operating currents. In this paper we describe the experimental setup and procedures, before reporting the main results, including statistics of magnet-to-magnet reproducibility and integrated field quality. Finally, we show how the measured data can be exploited for an optimal 3D alignment of the dipoles in the machine.

A flexible and easy-to-implement management structure for large amount of measurement and test da... more A flexible and easy-to-implement management structure for large amount of measurement and test data is proposed. Its main aim is to cope with industrial and research environment where the difficulty to make measurements requires to minimise the number of measurements campaigns and maximize the use of the data taken in these campaigns. This goal is achieved by providing well-defined structures for raw data storage and Data Base storage and clear separation between the analysis processes. A case study on test data of superconducting magnets for the Large Hadron Collider at the European Organization for Nuclear Research (CERN) is illustrated for managing present and future magnetic measurements requests.

The CAST experiment at CERN is the only running solar axion telescope. The first results obtained... more The CAST experiment at CERN is the only running solar axion telescope. The first results obtained so far with CAST-PHASE I is presented, which compete with the best astrophysically derived limits of the axion-tophoton coupling. The ongoing PHASE II of the experiment as well as the scheduled upgrades, which improve the axion discovery potential of CAST, are discussed.

Nuclear Physics B - Proceedings Supplements, 2005

Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by th... more Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by the Primakoff process. In a laboratory magnetic field (''axion helioscope''), they would be transformed into xrays with energies of a few keV. Using a decommissioned Large Hadron Collider test magnet, the CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axionphoton coupling g a < 1:16 10 ÿ10 GeV ÿ1 at 95% C.L. for m a & 0:02 eV. This limit, assumption-free, is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment over a broad range of axion masses.

Nuclear Physics B - Proceedings Supplements, 2003