Superconducting Single Particle Detectors (SSPD)

In modern photonics, SSPDs have become known as superconducting single photon detectors. 
They are nanoseconds fast, have a short dead time and may be well matched in area with typical single-mode fibres. Even infrared photons, with as little as 1 eV energy, can be detected with several percent efficiency.

In this project we have explored the applicability of SSPDs as single particle detectors, the reasoning being that thermal molecules can easily carry several eV of internal energy and may also couple to the quasi-particle system inside the superconducting strips.

The experiment showed that energetic atomic ions could be well detected, but also that there is a cussion of frozen gases on the chip - even in high and ultra-high vacuum - which prevents the counting of slow atoms or molecules. 

For fast particles the detection was rather significant. This result indicates that there is room for technology development, which may eventually render SSPDs interesting for neutral particle detection and certainly for ion mass spectrometry, as soon as the chip size exceeds the dimension of several millimeters.

Reference

• M. Marksteiner, A. Divochiy, M. Sclafani, P. Haslinger, H. Ulbricht, A. Korneev, A. Semenov, G. Gol'tsman, M. Arndt,
  A superconducting NbN detector for neutral nanoparticles,
  Nanotechnology 20 (2009).
• M. Sclafani, M. Marksteiner, F.M. Keir, A. Divochiy, A. Korneev, A. Semenov, G. Gol'tsman, M. Arndt,
  Sensitivity of a superconducting nanowire detector for single ions at low energy,
  Nanotechnology 23,  065501 (2012).