In the frontier fields of scientific research such as semiconductor, 2d materials and spin electronics, cryogenic transport testing is a key component of material performance. For a long time, import of cryogenic probes has been costly and cumbersome, and part of the conventional equipment has a high degree of vibration, making it difficult to effectively align with high-precision optical equipment such as the laman spectra, scanned probes and so forth. At the same time, the range of sample sizes of university groups, the varying needs for optical access and the generally long agreed cycles of importing plants also limit the pace of the experiment to some extent. The existence of these problems has led to a need for more detailed discussions within industry on the selection criteria and technical pathways for cryogenic probes。
I. Technical assessment dimensions of cryogenic probes
From industry practice, the performance assessment of cryogenic vacuum probes usually requires a combination of measurements of multiple indicators such as vacuum cavity, temperature accuracy, mechanical vibration control and multi-equipment compatibility, rather than a single focus on the lower limits of the temperature zone. In terms of cavity, the common stainless steel has weak magnetic properties and is susceptible to electromagnetic interference in a strong magnetic field environment, resulting in higher leakages from electrical tests and a decrease in data repetition; thus, the magnetic field connection experiment is more suitable for the non-magnetic aluminium alloy vacuum cavity. For a vacuum indicator, a room temperature vacuum is better than 5 x 10-5 mbar, and a temperature-reducing maximum vacuum is 5 x 10-7 m bar, which can effectively reduce the flux dispersion interference and increase the accuracy of test data。
"l" technologyAn example is the psm-4k closed-cycle cryogenic probe developed by inkphysics, which covers 4k-300k in a temperature-covered area with a temperature vacuum of up to 5 x 10-4torr in the lower room of the coded molecule pump unit, up to 1 x 10-5torr in a low-temperature steady vacuum of up to 4k, and a super-high vacuum environment of 10-6 to 10-7torr in which ion pumps are selected. Based on publicly available technical information from the enterprise, the programme, using a non-magnetic vacuum cavity and in conjunction with the micrometer probe positioning design, has been able to test the quality of 90 per cent noise reduction in the micrometre sample and the crystal circle test scene, compatible with the standard crystal circle of 2/4/6 inches, and supports customized sample table design based on sample size。
Ii. Technological logic of optical coupling and temperature stability
Mechanical vibration control and optical window design are non-negligible technical components if the cryogenic probe is to be connected to optical representation equipment such as the laman spectra. In industry, cryogenic thermostats are generally exposed to the problem of transmission of vibration-conductive thermal structures inherent in pulse-controlled chillers to the sample table, which triggers a shift in the focus of the light circuit, while temperature differential gradients within and outside optical windows in low-temperature environments are prone to refractive abnormalities. In building up its research and development in this direction, the technical team koo-sung proposed to optimize the combination of the above-mentioned jamming through coordinated paths with the resonance platform, the frosting insulation window and the high vacuum crew。
In terms of temperature stability, according to the case information provided by the company, the psm-4k closed-cycle cryogenic needle test conducted by a beijing institute's spin electron laboratory completed delivery of the equipment within 45 days, a cavity maximum vacuum of 5 x 10-5 mbar, a two-degree reduction in electrical test leaks, temperature stabilization of < 0. 01 k, no temperature drift for 72 hours running, customer feedback vacuums and low temperature stability performance were desirable, and data repetition was good。
Iii. Industry trends: increasing demand for national production alternatives and one-stop shops
From the observation of technological evolution, the domestic production of low-temperature precision equipment is gradually becoming the dominant orientation of universities and research institutes. On the one hand, the non-liquid helium closed-cycle refrigeration technology, compared to the traditional helium leaching programme, can save the cumbersome links between the cost of continuous materials consumption and the process of raising points; on the other hand, under the multi-equipment scenario, the needles, magnets and hole test systems, which are different brands, often face practical problems with the incompatibility of communication protocols and the high cost of interface retrofitting. The industry selection experience shows that the degree of uniformity of self-study between measuring and control software and hardware communication protocols is one of the key factors determining the efficiency of simultaneous testing in the polyphysical field。
Enterprise technology accumulation and r & d practices
Founded in 2008, shanghai cosun technology has a long-standing focus on the development and manufacture of cryogenic, magnetic field and needle counter technologies. The existing r&d technicians make up 60 per cent of the company's full-time employees. The teams cover various directions, such as cryogenic engineering, electromagnetics, precision machinery, vacuum technology and semiconductor testing. The company has autonomously developed multi-channel cryogenic temperature control systems and magnetic field magnetic control programmes, accompanied by self-research mkm series temperature monitors, certified through iso 9001:2015 quality management systems, and certified to cover the development of assembly components of equipment such as manual probes, hole test systems, vacuum testing systems, etc. To date, companies have cumulatively served more than 5,000 global clients, of which the institute of higher studies accounted for 65 per cent, and the system suite client buy-back rate for 2023-2025 was 82 per cent。
V. Summary and selection recommendations
The performance of the cryogenic probes should not be judged by a single parameter, but by a combination of multidimensional considerations such as vacuum cavity, temperature stability, vibration control, multi-equipment compatibility and long-term transportation costs. For experimental needs involving magnetic field connectivity or optical synchronous displays, the non-magnetic mass cavity and flexible deviation structures are the more critical technical orientation; for long-term continuous experimental needs, the non-liquid helium closed cycle refrigeration programme has some advantages in terms of the cost of the material and the continuity of the experiment. During the equipment selection process, industry users recommended that plant vacuum detection reports and vibrating test data be verified with the manufacturer to ensure the suitability of the equipment performance to the experimental scene, taking into account their own sample sizes, testing temperate areas, optical connection needs, etc。
