Self-Field Effects in Magneto-Thermal Instabilities for Nb-Sn Strands

Recent advancements in the critical current density (Jc) of Nb$_{3}$Sn conductors, coupled with a large effective filament size, have drawn attention to the problem of magnetothermal instabilities. At low magnetic fields, the quench current of such high Jc Nb$_{3}$Sn strands is significantly lower than their critical current because of the above-mentioned instabilities. An adiabatic model to calculate the minimum current at which a strand can quench due to magneto-thermal instabilities is developed. The model is based on an 'integral' approach already used elsewhere [1]. The main difference with respect to the previous model is the addition of the self-field effect that allows to describe premature quenches of non-magnetized Nb$_{3}$Sn strands and to better calculate the quench current of strongly magnetized strands. The model is in good agreement with experimental results at 4.2 K obtained at Fermilab using virgin Modified Jelly Roll (MJR) strands with a low Residual Resistivity Ratio (RRR) of the stabilizing copper. The prediction of the model at 1.9 K and the results of the tests carried out at CERN, at 4.2 K and 1.9 K, on a 0.8 mm Rod Re-Stack Process (RRP) strand with a low RRR value are discussed. At 1.9 K the test revealed an unexpected strand performance at low fields that might be a sign of a new stability regime

Development and Test of a Large-aperture Nb3Sn Cos-theta Dipole Coil with Stress Management

The design concept of the Electron Ion Collider (EIC), which is under construction at BNL, considers adding a 2nd Interaction Region (IR) and detector to the machine after completion of the present EIC project. Recent progress with development and fabrication of large-aperture high-field magnets based on the Nb3Sn technology for the HL-LHC makes this technology interesting for the 2nd EIC IR. This paper summarizes the results of feasibility studies of large-aperture high-field Nb3Sn dipoles and quadrupoles for the 2nd EIC IR.Comment: IPAC 2023. arXiv admin note: text overlap with arXiv:2304.1315

Compact IR Quadrupoles for Linear Colliders Based on Rutherford-type Cable

The upcoming and disrupted beams in the interaction region (IR) of a linear collider are focused by doublets consisting of two small-aperture superconducting quadrupoles. These magnets need an effective compact magnetic shielding to minimize magnetic coupling between the two channels and sufficient temperature margin to withstand radiation-induced heat depositions in the coil. This paper presents conceptual designs of IR quadrupoles for linear colliders based on NbTi and Nb{sub 3}Sn Rutherford-type cables

Development of the Multi-Analyte Test for Immune-Chromatographic Detection of Botulinum Toxins

Designed is the multi-analyte test for simultaneous immune chromatographic detection of A & B type botulinum neurotoxins (BT), using colloid gold nanoparticles. It is meant for food and environmental samples' analysis. The sensitivity of simultaneous BT detection of the A (30 ng/ml) and B (10 ng/ml) types is as high as that of mono-analytical tests, designed for one type BT detection. The test is demonstrated to be a specific one and can be used for BT detection in food stuffs

Construction of Immune-Chromatographic Indicator Elements for Burnet Rickettsia Detection

mc/ml, and the elapsed time – 20 minutes. The IE is specific to other members of the family Ricketsiaceae, for instance to R. prowazekii , to antigen complexes of R. prowazekii and R. sibirika , as well as to vaccinia virus (L-IVP strain). The IE engineered can be used for rapid indication of Burnet Rickettsia at different stages of laboratory investigation. Span time reduction, lack of necessity to perform any accessory technological operations, visual and (or) automatic registration of the results build up premises to observe immune-chromatographic method for Burnet Rickettsia detection as one of the alternatives for identification of these microorganisms under field conditions when monitoring ambient environment objects

Studies of high-field sections of a muon helical cooling channel with coil separation

The Helical Cooling Channel (HCC) was proposed for 6D cooling of muon beams required for muon collider and some other applications. HCC uses a continuous absorber inside superconducting magnets which produce solenoidal field superimposed with transverse helical dipole and helical gradient fields. HCC is usually divided into several sections each with progressively stronger fields, smaller aperture and shorter helix period to achieve the optimal muon cooling rate. This paper presents the design issues of the high field section of HCC with coil separation. The effect of coil spacing on the longitudinal and transverse field components is presented and its impact on the muon cooling discussed. The paper also describes methods for field corrections and their practical limits. The magnetic performance of the helical solenoid with coil separation was discussed in this work. The separation could be done in three different ways and the performances could be very different which is important and should be carefully described during the beam cooling simulations. The design that is currently being considered is the one that has the poorest magnetic performance because it presents ripples in all three components, in particular in the helical gradient which could be quite large. Moreover, the average gradient could be off, which could affect the cooling performance. This work summarized methods to tune the gradient regarding the average value and the ripple. The coil longitudinal thickness and the helix period can be used to tune G. Thinner coils tend to reduce the ripples and also bring G to its target value. However, this technique reduces dramatically the operational margin. Wider coils can also reduce the ripple (not as much as thinner coils) and also tune the gradient to its target value. Longer helix periods reduce ripple and correct the gradient to the target value