The upgrade of the LHC collimation system includes additional collimators in the LHC lattice. The longitudinal space for the collimators can be obtained by replacing some LHC main dipoles with ...shorter but stronger dipoles compatible with the LHC lattice and the existing powering circuits, cryogenics, and beam vacuum. A joint development programme aiming at building a 5.5 m long two-in-one aperture Nb 3 Sn dipole prototype suitable for installation in the LHC is being conducted by FNAL and CERN. As part of the first phase of the programme, 1 m and 2 m long single aperture models are being built and tested. Later on, the collared coils from these models will be assembled and tested in a two-in-one aperture configuration in both laboratories. A 2 m long practice model made of a single coil wound with Nb 3 Sn cable, MBHSM101, was developed and constructed at CERN. It has been completed, and tested at both 4.3 K and 1.9 K. This practice model features collared coils based on removable pole concept, S2-glass cable insulation braided over a mica layer, and coil end spacers made of sintered stainless steel with springy legs. The paper describes the main features of this practice model, the main manufacturing steps and the results of the cold tests.
To produce a continuous magnetic field of at least 8.5 T in a 1.1 m cold bore diameter, the superconducting outsert of the Grenoble Hybrid magnet is based on the novel development of a Nb-Ti/Cu ...Rutherford Cable On Conduit Conductor (RCOCC) cooled to 1.8 K by a bath of superfluid helium pressurized at atmospheric pressure. The main results of the conductor studies and development are presented after a brief introduction to the specificity of hybrid magnets, namely the electromagnetic couplings between resistive and superconducting coils. Results obtained with short samples of conductor are reviewed including the measurements of the elastic limit, AC losses, stability and critical current. The final specification of the RCOCC is presented highlighting the proposed method for the industrialization of the insertion process of the Rutherford cable on the hollow Cu-Ag stabilizer as well as its validation phase on short samples.
The CERN Large Hadron Collider (LHC) is envisioned to be upgraded in 2020 to increase the luminosity of the machine. The major upgrade will consist in replacing the NbTi quadrupole magnets of the ...interaction regions with larger aperture magnets. The Nb 3 Sn technology is the preferred option for this upgrade. The critical current density J c of Nb 3 Sn strands have reached sufficiently high values (in excess of 3000 at 12 T and 4.2 K) allowing larger aperture/stronger field magnets. Nevertheless, such large J c values may cause magneto-thermal instabilities that can drastically reduce the conductor performance by quenching the superconductor prematurely. In Nb 3 Sn magnets, a relevant parameter for preventing premature quenches induced by magneto-thermal instabilities is the Residual Resistivity Ratio (RRR) of the conductor stabilizing copper. An experimental and theoretical study was carried out to investigate how much the value of the RRR affects the magnet stability and to identify the proper conductor specifications. In this paper the main results are presented and discussed.
Abstract
Funding Acknowledgements
Type of funding sources: None.
Introduction
While early diagnosis and treatment initiation is crucial in cardiac amyloidosis (CA), the diagnosis is currently mostly ...established in advanced stages of the disease. Cardiac magnetic resonance imaging (CMR) with late gadolinium enhancement (LGE) provides excellent sensitivity for the diagnosis of CA. A diffuse subendocardial or transmural LGE pattern independent from coronary perfusion areas is considered characteristic of CA.
Purpose
While there is a distinct LGE pattern in later stages of CA, CMR characteristics during early stages are not established. In this retrospective study, we sought to identify potential early CMR indicators of CA.
Methods
Patients undergoing CMR at our center between 2012 and 2022 were retrospectively screened. Those with at least two CMR studies, of which only the latter demonstrated LGE characteristic for CA, were included. All patients underwent CINE and LGE imaging.
Results
Fifteen patient (80% male; median age 76 73–79 at first CMR) were included in this analysis. Median time interval between the two CMR studies was 4 years. We observed differences in left ventricular morphology between the initial and follow-up CMR (IVS 15±3 vs. 17±3 mm, p = 0.003; EDV 128±40 vs. 139±39, p = 0.02). LV function was preserved and did not differ between the two CMR (EF 65±10 vs. 62±9 %, p = 0.14). While an LGE pattern characteristic for CA was present in all patients on follow-up CMR, severe left ventricular hypertrophy (IVS >14 mm in 60%), atrial LGE (67%) and focal non-ischemic LGE of the posterolateral basal LV wall (87%) were identified as highly prevalent findings during the initial CMR already.
Conclusions
Based on these observations, we hypothesize that the combination of certain CMR characteristics (severe septal hypertrophy, atrial LGE and LGE of the basal posterolateral LV) may help to identify CA at an early stage. Prospective studies are needed to further investigate this hypothesis.
Abstract
Funding Acknowledgements
Type of funding sources: None.
Background
Pericarditis is frequently encountered in daily clinical practice and accounts for about 5% of chest pain hospital ...admissions 1. Although the diagnosis of pericarditis can be established by clinical criteria, cardiovascular magnetic resonance (CMR) imaging is increasingly used to evaluate concomitant myocardial involvement and/or to exclude other disease entities. Besides well-known morphologic findings like pericardial effusion, thickening or adhesion, pericardial late gadolinium enhancement (LGE) imaging has been demonstrated to be the most sensitive surrogate of pericarditis 2.
Purpose
While there is a lot of data regarding the optimal timing of LGE for the detection of myocardial damage, optimal timing of LGE for the detection of pericarditis is unknown. In the recent advent of rapid high-throughput CMR protocols, high diagnostic accuracy needs to be maintained not only for myocardial diseases, but also for the assessment of the pericardium.
Methods
We present a case series comparing pericardial contrast enhancement in rapid routine LGE images versus LGE images acquired following a longer waiting time after Gadolinium injection (gadoteridol).
Results
After a longer than rapid clinical routine waiting time, we observed more prominent pericardial signal enhancement in the setting of pericarditis. This effect is most likely explained by different pericardial Gadolinium distribution kinetics compared to the myocardium.
Conclusion
Consequently, this observation should be taken into account when imaging patients with suspected pericarditis and may warrant further evaluation.
Figure: Routine LGE timing (top row) versus delayed LGE timing (bottom row) in 4 patients with pericarditis undergoing CMR
Exemplary LGE images in the top row were acquired routinely after ∼10 min. from contrast administration (0,15mmol/Kg), whereas same LGE slices in the bottom row were additionally acquired after a delayed waiting time (∼20 min.) from contrast injection (0,15mmol/Kg). Pericardial LGE was more prominent in delayed LGE imaging compared to routine LGE imaging.
This paper reports on the development of the Nb 3 Sn Rutherford cable for the EuCARD high-field dipole magnet FRESCA2 designed to achieve a central field of 13 T at 4.2 K in a 100-mm bore. The ...FRESCA2 cable is rectangular and made of 40 strands of 1.0-mm diameter. The cable shall be able to carry a current of 15.7 kA at 4.2 K in a field of 15 T. In the first stage of cable development, focus was put on the cable parameters (cable width, cable mid-thickness and pitch length) to provide a cable made with Nb 3 Sn Powder-In-Tube strands achieving both a minimal critical current reduction of the strand during cabling and a good mechanical stability of the cable for coil winding. In the second stage of cable development, the cable was produced with Nb 3 Sn RRP strands. The cables, which were produced following an iterative process, were characterized and the results of the critical current measurements of extracted strands are discussed together with the cabling parameters and the type of strand.
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