Innovation
Where Technology Meets Vision
Innovation is not only about adopting new components or emerging technologies; it also requires rethinking the design approach — a significant challenge for an ambitious infrastructure like the WST.
Detectors
Scientific-grade visible detectors will be required for all three types of spectrographs. CMOS technology is increasingly replacing CCDs, marking a major transition that opens new possibilities.
Compared to CCDs, CMOS detectors offer several advantages, including lower read out noise, reduced cost, and higher operating temperatures. Their flexible readout modes—such as up-the-ramp sampling, already used in near-infrared sensors—could enable novel spectrograph operation schemes. Furthermore, compact, energy-efficient readout electronics could leverage ongoing innovations in the CMOS industry.
The potential to manufacture curved detectors is particularly promising, as it could simplify the spectrograph’s optical design by reducing the number of required optical surfaces—thereby lowering both complexity and cost. This is actively being explored, especially if the technology proves viable for more than just ground-based instruments. With its extensive detector array, WST could be an ideal platform to showcase these developments.
Cryostat
Each detector for the spectrographs will need to be cooled to an optimum operating temperature, typically around 150 K. To facilitate this, the detector is housed in a vacuum vessel with a window and a cooling system, known as a cryostat. These systems are often bulky, have complex electrical and cooling connections, and the cooling system is inefficient in terms of energy usage. The WST project is therefore designing a new type of cryostat that will have simplified connectivity and use less energy.
Diffraction gratings
Each spectrograph will use one or more diffraction gratings to split the light into a spectrum. As for the detectors, a huge number of them, with identical performances, will be necessary for the WST. Innovative technologies are explored, mainly focusing on the Volume Phase Holographic (VPH) approach.
Notably, for the high-resolution spectrographs, extremely large size gratings, of about half a meter size, will be selected, but at the moment, they are not available. A new big manufacturing facility is under construction at INAF to address such requests.
Moreover, the involvement of industries, both in Europe and the USA, is undergoing to find innovative solutions and alternatives.
Optical fibers
They are a key bridge from the focal plane to both the low- and high-resolution spectrographs. Their optical losses must be minimized, especially in the blue, to maximize the throughput, considering the long path in the infrastructure. Surely, improvements in the fibers are foreseen, and new approaches are potentially disruptive. Moreover, thousands of fibers must be managed precisely. Automatic systems are required to achieve this task in a reasonable time and with the required accuracy.
Toward SERIAL production
The WST will be an infrastructure made of identical or very similar “tech bricks”: hundreds of spectrographs, filters, diffraction gratings, and many more. Designing them with a serial production approach will be crucial to preserve the performances, minimising the production time, costs, and risks.
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The WST views sustainability as a core value
It guides the entire facility and consortium with dedicated, cross-disciplinary group supports this goal by providing guidelines, particularly for the design and construction phases.