A goal of the U.S. Magnet Development Program (US-MDP) is high-field magnets for accelerators with magnetic fields larger than 15 T, i.e., above the limits of Nb 3 Sn accelerator magnets. Composite ...round wires and Rutherford cables made of high temperature superconductor Bi2212 may achieve this goal. Bi2212 is sensitive to transverse stresses and strains, and this requires stress management in the coil design. A stress management approach was developed at Fermilab for high-field large-aperture Nb 3 Sn accelerator magnets. Now it is being applied to high-field dipole insert coils based on Bi2212 Rutherford cable. This paper describes the insert coil design and main parameters, including the superconducting wire and cable. The coil will be installed inside a 60-mm bore Nb 3 Sn dipole outsert coil and cold iron yoke. The Bi2212 coil will be tested individually and in series with the Nb 3 Sn outsert coil. The expected Bi2212 insert test parameters are reported and discussed.
This paper describes a 120-mm aperture 2-layer dipole coil with stress management (SM) developed at Fermilab based on cos-theta coil geometry. A model of the coil support structure made of plastic ...was printed using additive manufacturing technology and used for practice coil winding. The real coil support structure was printed using the 316 stainless steel. The results of the SM structure size control and the key coil fabrication steps are reported in the paper. The design of coil SM structure and the coil FEA in the dipole mirror test configurations are presented and discussed.
The U.S. Magnet Development Program (US-MDP) is developing high-field accelerator magnets with magnetic fields beyond the limits of Nb 3 Sn technology based on high temperature superconductor Bi 2 Sr ...2 CaCu 2 O 8-x (Bi2212). However, Bi2212 wires and cables are sensitive to transverse stresses and strains, which are substantial in high-field accelerator magnets. To prevent large degradation of the Bi2212 coils and achieve the required field quality, an innovative design which provides turn positioning during coil fabrication and operation and manage azimuthal and radial strains/stresses in the coil has been proposed at FNAL. This paper describes the development of a small-aperture two-layer Bi2212 dipole coil with stress management. The main parameters of the Bi2212 wire and Rutherford cable, the design of coil stress management structure and its plastic model, the coil mechanical analysis in the dipole mirror configuration are presented and discussed.
Towards 20 T Hybrid Accelerator Dipole Magnets Ferracin, P.; Ambrosio, G.; Arbelaez, D. ...
IEEE transactions on applied superconductivity,
09/2022, Letnik:
32, Številka:
6
Journal Article
Recenzirano
The most effective way to achieve very high collision energies in a circular particle accelerator is to maximize the field strength of the main bending dipoles. In dipole magnets using Nb-Ti ...superconductor the practical field limit is considered to be 8-9 T. When Nb 3 Sn superconductor material is utilized, a field level of 15-16 T can be achieved. To further push the magnetic field beyond the Nb 3 Sn limits, High Temperature Superconductors (HTS) need to be considered in the magnet design. The most promising HTS materials for particle accelerator magnets are Bi2212 and REBCO. However, their outstanding performance comes with a significantly higher cost. Therefore, an economically viable option towards 20 T dipole magnets could consist in an "hybrid" solution, where both HTS and Nb 3 Sn materials are used. We discuss in this paper preliminary conceptual designs of various 20 T hybrid magnet concepts. After the definition of the overall design criteria, the coil dimensions and parameters are investigated with finite element models based on simple sector coils. Preliminary 2D cross-section computation results are then presented and three main layouts compared: cos-theta, block, and common-coil. Both traditional designs and more advanced stress-management options are considered.
Background
YKL-40, also known as chitinase-3-like protein 1 (CHI3L1), is a secreted glycoprotein produced by various cell types including stromal, immune, and cancer cells. It contributes to cancer ...progression through tumor-promoting inflammation and has been shown to inhibit the cytotoxicity of T and NK lymphocytes.
In vivo
studies have demonstrated synergistic anti-cancer effects of blocking YKL-40 in combination with immune checkpoint inhibitors (ICIs). Biomarkers for the prediction of the response to ICIs are highly needed. We investigated the association between plasma YKL-40 and clinical benefit and survival in patients with metastatic pancreatic cancer (mPC) receiving ICIs and stereotactic body radiotherapy (SBRT).
Methods
Blood samples were collected from 84 patients with mPC who participated in the randomized phase II CheckPAC study, in which patients received nivolumab with or without ipilimumab combined with a single fraction of SBRT. Plasma YKL-40 was measured using a commercial ELISA kit.
Results
Elevated baseline plasma YKL-40 was an independent predictor of shorter overall survival (OS) (HR 2.19, 95% CI 1.21–3.95). A ≥ 40% decrease in plasma YKL-40 during treatment was associated with longer progression-free survival (
p
= 0.009) and OS (
p
= 0.0028). There was no correlation between plasma YKL-40 and the tumor burden marker CA19-9 at baseline or during treatment.
Conclusion
This study contributes new knowledge regarding YKL-40 as a predictor of clinical benefit from ICIs and radiotherapy. These exploratory results warrant further investigation of YKL-40 as a biomarker for patients treated with immunotherapies.
Clinical trial registration
Clinicaltrials.gov
, identifier NCT02866383.
MDPCT1 Quench Data and Performance Analysis Stoynev, S.; Baldini, M.; Barzi, E. ...
IEEE transactions on applied superconductivity,
09/2022, Letnik:
32, Številka:
6
Journal Article
Recenzirano
Odprti dostop
MDPCT1is a four-layer cos-theta Nb 3 Sn dipole demonstrator developed and tested at FNAL in the framework of the U.S. Magnet Development Program. The magnet reached record fields for accelerator ...magnets of 14.1 T at 4.5 K in the first test and 14.5 T at 1.9 K in the second test and then showed large degradation. While its inner coils performed exceptionally well with only two quenches up to 14.5 T and no evidence of degradation, the outer coils degraded over the course of testing. By adopting new measurement and analysis techniques at FNAL we are discussing in detail what happened. Both success and failure in our diagnostics are discussed. The evolution of techniques over the course of two tests (and three thermal cycles) shows the path to address challenges brought by the first four-layer magnet tested at FNAL. This paper presents the analysis of quench data along with diagnostic features and complementary measurements taken in support of the magnet performance analysis.
Hybrid magnets are currently under consideration as an economically viable option towards 20 T dipole magnets for next generation of particle accelerators. In these magnets, High Temperature ...Superconducting (HTS) materials are used in the high field part of the coil with so-called "insert coils", and Low Temperature Superconductors (LTS) like Nb 3 Sn and Nb-Ti superconductors are used in the lower field region with so-called "outsert coils". The attractiveness of the hybrid option lays on the fact that, on the one hand, the 20 T field level is beyond the Nb 3 Sn practical limits of 15-16 T for accelerator magnets and can be achieved only via HTS materials; on the other hand, the high cost of HTS superconductors compared to LTS superconductors makes it advantageous exploring a hybrid approach, where the HTS portion of the coil is minimized. We present in this paper an overview of different design options aimed at generating 20 T field in a 50 mm clear aperture. The coil layouts investigated include the Cos-theta design (CT), with its variations to reduce the conductor peak stress, namely the Canted Cos-theta design (CCT) and the Stress Management Cos-theta design (SMCT), and, in addition, the Block-type design (BL) including a form of stress management and the Common-Coil design (CC). Results from a magnetic and mechanical analysis are discussed, with particular focus on the comparison between the different options regarding quantity of superconducting material, field quality, conductor peak stress, and quench protection.
A 100-TeV-scale Hadron Collider (HC) with a nominal operation field of at least 15 T is being considered for the post-LHC era, which requires using the Nb 3 Sn technology. Practical demonstration of ...this field level in an accelerator-quality magnet and substantial reduction of the magnet costs are important requirements for realization of such a machine. Fermilab has started the development of a 15 T Nb 3 Sn dipole demonstrator for a 100-TeV-scale HC. The magnet design is based on optimized 60-mm-aperture four-layer shell-type coils, graded between the inner and outer layers to maximize the performance and reduce the cost. The experience gained during the Nb 3 Sn magnet R&D is applied to various aspects of the magnet design. This paper describes the magnetic and structural designs and parameters of the 15 T Nb 3 Sn dipole demonstrator and the steps toward its fabrication.
To evaluate the clinical benefit of nivolumab with or without ipilimumab in combination with stereotactic body radiotherapy (SBRT) in patients with refractory metastatic pancreatic cancer (mPC).
...Between November 2016 and December 2019, patients with refractory mPC were randomly assigned 1:1 to SBRT of 15 Gy with nivolumab or nivolumab/ipilimumab stratified by performance status (ClinicalTrials.gov identifier: NCT02866383). The primary end point was the clinical benefit rate (CBR), defined as the percentage of patients with complete or partial response (PR) or stable disease, according to RECIST 1.1. Simon's 2-stage phase II optimal design was used independently for both arms, with CBR determining expansion to the second stage. Secondary end points included safety, response rate, duration of response, progression-free survival, and overall survival. Exploratory analyses included biomarkers related to the benefits.
Eighty-four patients (41 SBRT/nivolumab and 43 SBRT/nivolumab/ipilimumab) received at least one dose of study treatment. CBR was 17.1% (8.0 to 30.6) for patients receiving SBRT/nivolumab and 37.2% (24.0 to 52.1) for SBRT/nivolumab/ipilimumab. PR was observed in one patient receiving SBRT/nivolumab and lasted for 4.6 months. Six patients receiving SBRT/nivolumab/ipilimumab achieved a PR with a median duration of response of 5.4 months (4.2 to not reached). Grade 3 or higher treatment-related adverse events occurred in 10 (24.4%) and 13 (30.2%) patients in the SBRT/nivolumab and SBRT/nivolumab/ipilimumab groups, respectively. Programmed cell death ligand-1 expression by tumor proportion score or combined positivity score of ≥ 1% was not associated with clinical benefits. On-treatment decreased serum interleukin-6, interleukin-8, and C-reactive protein levels were associated with better overall survival.
Clinically meaningful antitumor activity and favorable safety profiles were demonstrated after treatment with SBRT/nivolumab/ipilimumab in patients with refractory mPC. However, the contribution from SBRT is unknown. Further studies are warranted.
Abstract
Recent advances with additive manufacturing (AM) technologies using various materials allow them to be considered for the manufacture of precise and complicated metal parts of the magnet ...coils of high field accelerator magnets from aluminum bronze, titanium alloy, stainless steel, etc. The 3D printing technology is also being used to fabricate prototype models of real parts to test and optimize their geometry. This paper discusses the designs of the complex stress-management coil parts developed at Fermilab, their fabrication using AM technologies, and quality control methods and results.
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