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Superconducting Mass Spectrometry and Molecule Analysis

Periodic Reporting for period 2 - SuperMaMa (Superconducting Mass Spectrometry and Molecule Analysis)

Reporting period: 2021-01-01 to 2022-06-30

Mass spectrometry has become a multi-billion dollar market word-wide, because it allows one to quantitatively assess the molecular content of a sample and to retrieve molecular structure information.
SUPERMAMA now aims at breaking new scientific grounds for new technologies that shall boost the capabilities of mass spectrometry as well as of optical spectroscopy. Here we specifically target singly charged and neutral high-mass proteins.
SUPERMAMA will develop, test and combine the first integrated superconducting nanowire array (SNWA) with advanced cryogenic onboard electronics in a largely re-modelled ESI-TOF-machine. The efficient detection of massive biomolecules at low kinetic energy will be an important first milestone for mass spectrometry.
The development of a new generation of photocleavable tags shall allow the preparation of neutral protein beams from mass-selected ions in focused transverse high-power laser fields.
Photo-cleavage post-ionization of tagged proteins shall also be studied as a generic tool to decouple the volatilization from the charging process. This will enable the combination of a systematic analysis of neutral proteins in the gas phase with subsequent mass spectroscopy.
The combination of all techniques shall open new avenues for few-photon calorimetry and single-photon recoil spectroscopy. The calorimetry studies will explore the sensitivity of SNWA detection to molecular heat. Future experiments will study the shift of molecular matter-wave interference fringes caused by the recoil of a single photon.

Two industrial and three academic research teams represent a highly interdisciplinary consortium of experts from mass spectrometry, superconductor technology, integrated electronic engineering, synthetic chemistry, as well as molecular beam physics and quantum optics who work together in towards their joint goal to advance mass spectrometry and optical spectroscopy in a domain that has remained unexplored so far.
We have setup our management infrastructure, hired all required personnel, established the website and Twitter account, setup a common data sharing platform in own cloud as well as collaborative tools.

The first year was dedicated to the design and setup of the technology basis:

We have designed and fabricated new 8 pixel superconductor nanowire detectors in different configurations (linear & parallel, coated & uncoated, different line widths) including electronics and evaluation software.

We have and tested them both with photons in Delft and with atomic ions across a mass and energy range in VIenna.
For the ion tests a new cryogenic test stand was setup to acquire experience in handling the SNWD devices, how to keep them cold, and in ultra-high vacuum with intense ion flux entering.

The high sensitivity, in particular of the 100 nm x 10 nm wire SNWDs is promising for low energy particle detection, while the wide-line detectors are less sensitive but compatible with a larger detector area.
We could show that we can clearly discriminate ions and photons by their SNWD bias current and that one can chose a setpoint where only ions are detected with high certainty.
We have explored cleaning methods in case organic contaminants are accumulated on the SNWD surface.

The cryogenic electronics for multipixel readout was designed and simulated and sent for fabrication. Plans for the 2nd generation electronics wiith lower power consumption were made.

We have remodeled an ESI_TOF mass spectrometer to be able to add charge reduction at the ESI entrance stage, as well as optical charge reduction in two new zones after a quadrupole mass filter and buffer gas cooling stage. The extended mass spectrometer was simulated with a new ion switch and ion guide towards the new cryogenic detector. For that purpose the entire experiment was moved to a new lab and rebuilt from scratch. This was all done in close collaboration between MSVISION, Almere and UNIVIE.

We have synthesized new photocleavable peptide tags, which were optimized for green laser light, using Bodipy derivatives.
We have used the mass spectrometer, installed a new high-power ultra-fast laser to interact with these tailored molecules and to demonstrate photocleavage on demand.

The first year has brought all groups to the point of contributing genuine research data. These systems shall now be improved and upscaled towards peptide and protein selection, manipulation and detection,
the latter in particular also using advanced SNWD devices of increasing pixel number and improved sensitivity.
We are still in year 1 and currently working at the state of the art.
The goal is to achieve
a) more versatile and more universal tags that shall allow generic charge control on lowly charged polypeptides and proteins, from photo-neutralization to photo-ionization.
b) devise and run a versatile mass spectrometer that can select and cool massive proteins in low charge states
c) fabricate, test and utlize superconducting nanowire detectors, with more individually addressable pixels than in any other experiment before and at a low energy range that is complementary to all previous devices and that shall allow analyzing molecular properties, too.