APPLICATIONS OF MAGNESIUM DIBORIDE TO PARTICLE PHYSICS Riccardo
APPLICATIONS OF MAGNESIUM DIBORIDE TO PARTICLE PHYSICS Riccardo Musenich Istituto Nazionale di Fisica Nucleare Genova
Summary Historical introduction Applications of superconductors Superconductors in particle physics Applications of new materials Mg. B 2: overview italian programs INFN activity future INFN programs (if any)
1911 : discovery of superconductivity H. Kamerlingh Onnes, Commun. Phys. Lab. Univ. Leiden, 122 e 124, 1911
Starting from the fourties many superconducting materials, like niobium nitride and niobium-tin*, have been discovered, but only in 1962 the first “industrial scale” superconducting wires (based on niobium-titanium) have been developed by Westighouse. In 1986 HTCS (La 1. 85 Ba 0. 15 Cu. O 4, Tc=30 K) have been discovered**. The higher critical temperature for HTCS is 138 K (Hg 0. 8 Tl 0. 2 Ba 2 Cu 3 O 8. 33 )*** *** B. T. Matthias et al. , Phys. Rev. 95, 1435 (1954) J. G. Bednorz, K. A. Müller, Z. Phys. B, Cond. Matter, 64, 189 -193 (1986) P. Dai et al. , Physica C, 243, 201 -206 (1995)
Applications of superconductivity Energy production and transport Alternators Transformers Cables Energy storage (SMES) Current limiters (FCL) Trasports magnetic levitation motors MHD propulsion
Applications of superconductivity Electronics and communications filters antennas microprocessors Industrial applications Magnets for: magnetic separation crystal growth chemical processes Sensors SQUID
Applications of superconductivity Medicine MRI biomagnetic measurements Research laboratory magnets NMR spectrometers magnets for nuclear fusion accelerator components (magnets and rf cavities) superconducting detectors SQUID
WORLDWIDE SUPERCONDUCTIVITY MARKET YEAR 2000 M€ % R&D 415 18 (30) MRI 1900 (900) 80 (66) other applications 55 2 (4) TOTAL 2370 (1370) 100 CONECTUS , december 2001
Applications of HTCS (YBCO e BSCCO) At present, technical difficulties in handling the materials and high costs (200 €/k. A m) limit, the HTCS to niche applications. The technological research looks toward the energy transport and to devices like FCL and transformers. HTCS (YBCO e BSCCO) market: 15 M€ 1%
Among the research application, particle physics largely uses superconducting materials, mainly for magnets and accelerating cavities. The choice between resistive and superconductive devices is generally related to technical aspects: the superconductor technology is often the only possibility to achieve the required performances.
superconductivity in nuclear and subnuclear physics accelerating cavities Recyclotron STANFORD MUSL University of Illinois S-Dalinac Darmstat TRISTAN KEK HERA DESY CEBAF JEFFERSON LAB LEP CERN TESLA TF DESY J. Proch, Rep. Prog. Phys. , 61, 431 -482, 1998
superconductivity in nuclear and subnuclear physics accelerating cavities Argonne National Laboratory Stony Brook Florida State University of Washington CEN – Saclay JAERI INFN – LNL ANU – Canberra J. Proch, Rep. Prog. Phys. , 61, 431 -482, 1998
superconductivity in nuclear and subnuclear physics magnets for accelerators TEVATRON FNAL RHIC BNL HERA DESY LHC CERN (under construction)
superconductivity in nuclear and subnuclear physics magnets for accelerators Chal. K River S. C. Canada K 500 MSU K 800 INFN – LNS K 1200 MSU AGOR KVI Groningen + other 3 S. C. under construction
superconductivity in nuclear and subnuclear physics detector magnets The first large superconducting detector magnet was constructed in the sixties: it was the solenoid for the 12 ft bubble chamber of Zero Gradient Synchrotron (Argonne National Laboratory) CELLO DELPHI CDF ZEUS TOPAZ BABAR VENUS ATLAS ALEPH CMS
widest used superconducting materials : Nb-Ti (magnet conductors) Nb 3 Sn (magnet conductors) Nb (accelerating cavities) At present, the material under development are: alloyed Nb 3 Sn, Nb 3 Al, YBCO, BSCCO and Mg. B 2
superconductivity in nuclear and subnuclear physics materials for accelerating cavities RS=RBCS+RRES Pb Nb other material (Nb. N, Nb 3 Sn …) Niobium nitride
superconductivity in nuclear and subnuclear physics HTCS To reduce thermal load at low temperature, the LHC magnets will be equipped with HTCS current leads. This one is the first large scale application of the HTCS in high energy physics.
Mg. B 2 Tc = 39 K ITCS Mg. B 2 is the binary compound with the highest critical temperature J. Nagamatsu, N. Nakagawa, T. Muranaka, Y. Zenitani, J. Akimitsu Nature 410 63 (2001)
The material characteristics technological applications: seems favourable for • high critical temperature (39 K) • Bc 2 15 T • no weak links ( =5 nm) • low anisotropy • high critical current density (Jc 5 109 A/m 2 a 20 K e 0 T) • low cost (extimated: 5 €/k. A m) On the other hand, the irreversibility field is relatively low: 4 Tesla at 20 K
Thanks to the know-how and the technologies developed for the production of HTCS conductors, few month after the discovery of the superconducting properties of Mg. B 2, wires and tapes became available in several meter lengths.
production technique of magnesium diboride conductors: in situ Powder in tubes (PIT) ex situ
Like Nb 3 Sn, Mg. B 2 requires a high temperature heat treatment to achieve good transport properties*. Two routes can be followed to construct a magnet: REACT & WIND & REACT * Ex-situ PIT conductors have high critical current even without heat treatment!
Thin films can be deposited by : from Mg. B 2 cathode Sputtering from precursor cathodes reactive sputtering Evaporation Laser ablation
Resonant cavities Thin Mg. B 2 films Squid Detectors
Mg. B 2 Research programs on Mg. B 2 in Italy
Research (mainly fundamental) with ordinary funds (CNR, INFM, Universities) Industrial R&D (Ansaldo Superconduttori, Columbus Superconductors, Edison, Europa Metalli, Pirelli) INFN (Ma-Bo project) 2002 -2004 INFM (MIUR funded project) 2004 -2006
Ma-Bo the INFN program (2002 -2004) on magnesium diboride applications to nuclear and particle physics Genova Frascati National Laboratories Legnaro National Laboratories Milano Napoli Torino 30 people involved (about 10 FTE).
Ma-Bo The research project Ma-Bo aims to understand if magnesium diboride could be used for particle physics applications. The research activities are related to: Magnets Thin films for cavities Thin films for detectors and other devices
Ma-Bo is in collabotation with: ENEA INFM Universities Ansaldo Superconduttori Columbus Superconductors
Thin films I=1 A B Cathodes V = 400 460 V Mg. B 2 Mg t = 10 min Plasma Ar atmosphere Mg pellets Substrate Nb box Platform T “cold” Heater R. Vaglio, INFN and University of Naples
Problems in using Mg. B 2 for rf resonant cavities: – Mg. B 2 is a double gap superconductor – A homogeneous, pure (single phase) film must be deposited onto large area substrates – The material is chemically instable (exposed to the atmosphere)
f = 20 GHz e-D/KT Rs res 1 m. W R. Vaglio, INFN and University of Naples
XPS spectrum of a Mg. B 2 film
XPS spectrum of a Mg. B 2 film (B 1 s)
XPS spectrum of a Mg. B 2 film (Mg 2 s)
magneto-optical analysis on Mg. B 2 films Dendritic flux penetration B(m. T) E. Mezzetti, INFN and Politecnico di Torino
Production of Mg. B 2 tape (PIT method) at LAMIA laboratory (INFM) 3. 5 mm x 0. 3 mm SC fill factor 15 -20% 100 meters
10 n 1000 G. Grasso, INFM–LAMIA Genova
G. Grasso, INFM–LAMIA Genova
Mg. B 2 “React&Wind” solenoid wound by Ansaldo Superconduttori with 80 m long INFM/Columbus tape Ø 145 mm
React & wind technique 6 layers 27 turns/layer Diameter = 15 cm B = 1. 35 m. T/A, (coil center) B = 2. 15 m. T/A (BMAX at the conductor)
Solenoid test in liquid helium bath Superconducting for most of the length No resistance observed at the layer joggle Localized dissipation at the inner electrical exit Despite the localizad dissipation (4 W at 47 A) the solenoid was able to carry 53 A before quenching (11 m. T at the conductor, 6 m. T at coil center)
20 cm Pancake coil wound by Ansaldo Superconduttori with 40 m tape (INFM/Columbus Superconductors)
Test of the pancake coils in liquid helium bath Both the coils were fully superconducting Pancake #1 reached 215 A (BMAX=0. 47 T, BC= 0. 13 T) Pancake #2 reached 335 A (BMAX=0. 74 T, BC= 0. 20 T)
Several problems must be solved but the feasibility of Mg. B 2 magnets is clearly demonstrated
Perspective for ITCS (Mg. B 2) in nuclear and subnuclear physics Easy to produce. Low cost of the material. No weak link. High critical current density. applications: cryogen free, low field, superconducting magnets
Improvement of Mg. B 2 properties Powder density Grain dimension Nanoparticles inclusions Lattice disorder Doping Texturing Jc Hc 2, Hirr
CONCLUSIONS At present, superconducting devices like cavities and magnets, based on niobium and niobium-titanium respectively, are largely used in particle physics. Till now, neither Mg. B 2 nor other superconducting materials can compete with niobium for application in accelerating cavities. Among the new superconductors, magnesium diboride seems a good candidate for the construction of magnets. Low field magnets will be probably the first step but there are several indication about the possibility of a field improvement.
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