123519490
BSCCO-2212 Wire and Cable Studies
BSCCO-2212 round wires and cables are being studied for possible use in very high field magnets (>; 25 T) within the multi-Lab Very High Field Superconducting Magnet Collaboration (VHFSMC). Billets produced by Oxford Superconducting Technology were used to make Rutherford-type cables of various geometries. The effect of the cable parameters was measured on the extracted strand performance and deformation. Transport properties were measured at 4.2 K in fields up to 14 T for the extracted strands across the edges, and compared with as-received round wire. The same wire used in the cables was also deformed by flat rolling to reproduce the deformation seen by the round strand when formed into a Rutherford cable. After heat treatment, rolled samples were characterized for transport properties and results compared to those obtained for strands extracted from the cables. Finally cables were tested at 4.2 K and self-field using a superconducting transformer and results compared to those of the extracted strands.
135206500
Study of YBCO tape anisotropy as a function of field, field orientation and operating temperature
Superconducting magnets with magnetic fields above 20 T will be needed for a Muon Collider and possible LHC energy upgrade. This field level exceeds the possibilities of traditional Low Temperature Superconductors (LTS) such as Nb{sub 3}Sn and Nb{sub 3}Al. Presently the use of high field high temperature superconductors (HTS) is the only option available for achieving such field levels. Commercially available YBCO comes in tapes and shows noticeable anisotropy with respect to field orientation, which needs to be accounted for during magnet design. In the present work, critical current test results are presented for YBCO tape manufactured by Bruker. Short sample measurements results are presented up to 14 T, assessing the level of anisotropy as a function of field, field orientation and operating temperature.
116294626
Nb3Sn cable development for the 11 T dipole demonstation model
Fermilab (FNAL) and CERN have started the development of 11 T 11-m long Nb{sub 3}Sn dipoles to replace a number of LHC NbTi dipoles and free space for cold collimators in the LHC DS areas. An important step in the design of these magnets is the development of the high aspect ratio Nb{sub 3}Sn cable to achieve the nominal field of 11 T at the nominal LHC operating current of 11.85 kA at 1.9 K with 20% margin. Keystoned cables with 40 and 41 strands with and without a stainless steel core were made out of hard Cu wires and Nb{sub 3}Sn RRP strand of 0.7 mm nominal diameter. The cable optimization process was aimed at achieving both mechanical stability and minimal damage to the delicate internal architecture of the Restacked-Rod-Process (RRP) Nb3Sn strands with 127 restack design to be used in the magnet short models. Each cable was characterized electrically for transport properties degradation at high field and for low field stability, and metallographically for internal damage.
136958824
Insert Coil Test for HEP High Field Magnets Using YBCO Coated Conductor Tapes
The final beam cooling stages of a Muon Collider may require DC solenoid magnets with magnetic fields of 30-50 T. In this paper we present progress in insert coil development using commercially available YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} Coated Conductor. Technological aspects covered in the development, including coil geometry, insulation, manufacturing process and testing are summarized and discussed. Test results of double pancake coils operated in liquid nitrogen and liquid helium are presented and compared with the performance of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} tape short samples.
123481944
STUDY OF HTS INSERT COILS FOR HIGH FIELD SOLENOIDS
Fermilab is currently working on the development of high field magnet systems for ionization cooling of muon beams. The use of high temperature superconducting materials (HTS) is being considered for these solenoids using Helium refrigeration. Several studies have been performed on insert coils made of BSCCO-2223 tapes and second generation (2G) YBCO coated conductors, which are tested at various temperatures and at external fields of up to 14 T. Critical current (I{sub c}) measurements of YBCO short samples are presented as a function of bending stress, magnetic field and field orientation with respect to the sample surface. An analytical fit of critical current data as a function of field and field orientation is also presented. Results from several single-layer and double-layer pancake coils are also discussed.
118446092
ANGULAR MEASUREMENTS OF HTS CRITICAL CURRENT FOR HIGH FIELD SOLENOIDS
An experiment is in the works at Fermilab to confirm that ionization cooling is an efficient way to shrink the size of a muon beam. This would pave the way for Muon Collider machines, which however require in their last stages of acceleration very high field solenoids. The use of high temperature superconducting materials (HTS) is being considered for these magnets using Helium or higher temperature refrigeration. A sample holder was designed to perform critical current (Ic) measurements of HTS conductors under externally applied magnetic fields varying from zero to 90 degree with respect to the c‐axis. This was performed in an ample range of temperatures and magnetic field values. A description of the test setup and results for (Bi,Pb)2Sr2Ca2Cu3Ox (BSCCO‐2223) tapes, and Second Generation HTS in the form of 348 superconductor are presented.
118793567
Hadronic B decays at BaBar and Belle
The authors review recent results of the BABAR and Belle Collaborations on the {alpha} and {gamma} angles of the unitarity triangle, on the B {yields} K{pi}{pi} Dalitz-plot analyses, and on the searches for baryonic B decays and for B {yields} D{bar D} decays.
117666088
Measurement of the CKM Angles alpha and gamma at the BaBar Experiment
We present recent measurements of the CKM angles alpha and gamma using data collected by the BaBar detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at the Stanford Linear Accelerator Center. In addition to constraints on alpha from the decays B0 {yields} {pi}{sup +}{pi}{sup -}, B0 {yields} {rho}{sup +} {pi}{sup -} and B0 {yields} {rho}{sup +}{rho}{sup -}, we also report the first measurement of time-dependent CP asymmetries in the decay B0 {yields} a1{sup +}(1260) {pi}{sup -}. We present measurements of gamma in B+ {yields} D(*)0 K+ decays using a Dalitz analysis in the modes D{sup 0} {yields} Ks {pi}{sup +}{pi}{sup -} and D{sup 0} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup 0}. We present recent measurements of the CKM angles alpha and gamma using data collected by the BaBar detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at the Stanford Linear Accelerator Center. In addition to constraints on alpha from the decays B0 -> {pi}{sup +}{pi}{sup -}, B0 {yields} {rho}{sup +} {pi}{sup -} and B0 {yields} {rho}{sup +}{rho}{sup -}, we also report the first measurement of time-dependent CP asymmetries in the decay B0 {yields} a1{sup +}(1260) {pi}{sup -}. We present measurements of gamma in B{sup +} {yields} D(*)0 K+ decays usingmore » a Dalitz analysis in the modes D{sup 0} {yields} Ks {pi}{sup +}{pi}{sup -} and D{sup 0} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup 0}.« less
14255912
Measurements of charmless B decays related to alpha at BaBar
We report recent measurements of the CKM angle {alpha} using data collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory. In addition to improved constraints on {alpha} from the decays B{sup {+-}} {yields} {rho}{sup {+-}}{rho}{sup 0}, we also present preliminary results of neutral and charged B meson decays to K{sub 1}(1270){pi} and K{sub 1}(1400){pi} and its impact on the estimate for the CKM angle {alpha} based on time-dependent analysis of CP-violating asymmetries in B{sup 0} {yields} a{sub 1}(1260){sup {+-}} {pi}{sup {-+}}. Moreover we report the first observation of the decay B {yields} a{sub 1}(1260){sup {+-}}a{sub 1}(1260){sup {-+}}; this mode can be used, in principle, to provide an independent measurement of {alpha}.
124128361
Branching Fractions in B0 Meson Decays to a1+-(1260) pi-+ and a1+-(1260)K-+