Speaker
Description
The HTS4 project, part of the CHART framework and the FCC Feasibility Study, investigates energy-efficient nested high-temperature superconducting (HTS) magnet systems for the FCC-ee short straight sections (SSS). Replacing selected normal-conducting magnets with nested ReBCO-based variants can reduce electricity consumption through two mechanisms: elimination of ohmic magnet losses and an increased dipole filling factor, which lowers the synchrotron-radiation power. The increased filling factor may also reduce the required RF voltage and, consequently, the scale and cost of the RF system.
We present a coupled electromagnetic, thermal, and economic optimization workflow for determining the preferred operating temperature and cooling-system architecture of the nested HTS magnets. Electromagnetic feasibility and field quality are evaluated using a two-dimensional finite-element model. For each configuration, the current-sharing temperature is calculated from the J_c scaling law. The cold heat load is determined using a component-level model that includes multilayer-insulation radiation, structural conduction, beam-induced heating, parasitic loads, and powering-related losses.
For conduction-cooled configurations, cryocooler cooling power and electrical input power are calculated using fitted manufacturer load-map data within the experimentally characterized operating range. The model also accounts for the thermal load of inactive coldheads in redundant configurations and constrains both the heat lift and electrical input per active coldhead. Distributed cryocoolers are compared with distribution-line concepts supplied by centralized cryogenic plants, together with alternative magnet-powering schemes.
The analysis is applied to both the LCC and GHC magnet configurations, to quantify how their different electromagnetic and thermal requirements affect the preferred operating temperature, cooling architecture, cooler count, redundancy, conductor amount, and electrical input power. For the LCC configuration, the present baseline favors distributed conduction cooling at a cold-sink temperature of around 40-50 K. Comparison with the GHC configuration establishes how the magnet and layout requirements shift the preferred cooling concept and operating point. More generally, the study identifies the principal design and cost trade-offs for large-scale deployment of HTS magnets in the FCC-ee short straight sections and the conditions under which they could become competitive with the normal-conducting reference.
This work was performed under the auspices of and with support from the Swiss Accelerator Research and Technology (CHART) program (www.chart.ch).
| Submitters Country | Switzerland |
|---|---|
| Are you a student? | No |
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