BRAIN IMAGING WITH ARRAYS OF QUANTUM SENSORS

Project Information

Brainiaqs

Grant agreement ID: 951991

DOI

10.3030/951991

Project closed

EC signature date 18 May 2020

Start date 16 October 2020

End date 15 April 2023

Funded under

• EXCELLENT SCIENCE - Future and Emerging Technologies (FET)

Total cost

€ 1 999 998,75

EU contribution

€ 1 999 998,75

Coordinated by

SINGLE QUANTUM BV
Netherlands

Periodic Reporting for period 2 - Brainiaqs (BRAIN IMAGING WITH ARRAYS OF QUANTUM SENSORS)

Reporting period: 2022-01-16 to 2023-04-15

Summary of the context and overall objectives of the project

Fundamental new insights in life sciences have often been enabled by new scientific tools based on new technologies. In particular, optical techniques are quickly gaining ground in biological imaging because they allow for precise and non-invasive imaging along with the ability to label and identify specific molecules while avoiding ionization in contrast to, for instance, X- rays. Optical techniques can be used in fundamental studies and diagnostics, as well as to monitor emerging photo-therapies targeting cancer cells. Yet for many real-world applications, optical technologies still face considerable challenges due to limited detector performances in the infrared, a spectral region that holds very important potentials to improve image contrasts, monitor new processes and image far deeper in tissues. While outstanding infrared detectors are available with very limited pixel numbers for tis spectral range, biological imaging requires large arrays of high-performance optical sensors. In this project we will push state of the art sensor arrays from 2x2 pixels to 10x10 pixels to enable and demonstrate new brain imaging techniques.
The objectives are:
1) Develop a 100-pixel array of quantum sensors based on superconducting nanowire single-photon detectors
2) Develop a near-IR Multi-Photon Microscopy system specifically designed to operate with near-IR chromophores and implement the detector of objective (1).
3) Use the near-IR Multi-Photon Microscopy system to noninvasively image biological functions in a mouse brain at millimetre depth.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

We produced large area multi-pixel detection systems integrated with a scalable cryogenic electronic platform. An important concept is based on the development of a closed cycle cryostat with high enough cooling power for a one hundred pixels that is still compact and easy-to-use. Current single-pixel devices are cooled using low power cryogenic cooling units. The current cooling power is not sufficient to cool the large arrays of superconducting sensors proposed in this project. Cryogenic cooling units that have far more cooling power than what is currently used by Single Quantum are available.
We designed and fabricated arrays of superconducting quantum sensors organized in bins for spectroscopy and imaging achieving high efficiency (up to 90%), low dark counts (down to 10 cps) and an ultrahigh time resolution (<10 ps) both in the visible and near-infrared. So far we have shown that we can scale up the detectors to 24 pixels, with an active area of about 50x50 micrometer.

The readout electronics that sense and amplify the photon detection signal have a significant influence to the overall detector characteristics, such as timing jitter, reset times and maximum count rates. Cryogenic low-noise amplification of extremely weak SNSPD output signal can significantly improve the signal-to-noise-ratio, thereby minimizing timing jitter. We have designed, characterized and implemented the first low noise amplifiers based on SiGe for operation with SNSPDs.

We call the Brainiaqs array of quantum sensors, together with the optical cryostat, the scalable electronics and low noise amplifiers the SQCam and during the second reporting period tried to widely disseminate this product amongst scientists working on bio-imaging. We have attended several conferences and showed the developments there.

To show the innovation potential of the newly developed instrument we have also implemented the detectors in a multi-photon microscope and performed in-vitro and in-vivo bioimaging experiments. This has been done in close collaboration with project partner EMBL that will allow us to further tailor the microscope’s performance parameters for utmost practicality and impact. During the final phase of the project convincing measurements were performed that showed the advantage of using the SQCam over conventional detection techniques in microscope. We have also reached the final objective (3) by imaing a mouse brain at millimetre depth.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The 24 pixel SNSPD is the first detector this large that is commercially available. Operating this in our new cryostat could open a wide range of applications.
So far, low noise amplifiers traditionally obtained with InP HEMT amplifiers. Recently, silicon SiGe HBT technologies have shown to obtain noise figures comparable to InP HEMTs7. The benefit of silicon technologies is their better integration capabilities that is essential for large arrays along with low power consumption and good performances in the DC-3GHz range where we need amplification. So far this type of amplifiers has never been used with sensors based on superconducting nanowires, however it is expected a design can be made that is suitable to amplify the signal of these type of sensors. For the bio-imaging application the detectors were compared to traditional detectors. We have shown multi-photon in-vivo imaging at a record depth.

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