Atom Based Quantum Sensors (ABaQuS)

Cold atoms as a pressure or flux sensor

Cold atoms are an ideal sensor for particle flux detection in an ultra-high vacuum environment. Very simply, the passage of a particle through the collision cross section of the atom is announced by the resulting collision recoil of (i.e. momentum transfer to) the cold atom. In this way, the sensor element is the atom itself – an ageless and unchanging object. The detection mechanism is based on a fundamental and unchanging property – the Van der Waals interaction potential between the sensor atom and the particles being measured. The idea is very simple yet extremely powerful as it provides a way to obtain an absolute measure of the particle flux or background density at pressures below 10$^{-6}$ Torr. Such absolute measurements are not presently possible with existing technology – ionization based gauges require calibration and therefore do not provide a reliable and absolute measure of vacuum. Preliminary theoretical and experimental work with argon indicated that this sensor technology works as expected. Extensive research has also been conducted to fully characterize the physics of cold-atom traps in order to realize the proposed sensor. Our next goal is to establish cold atom based sensors as a new international pressure and particle flux standard, and we have entered into a formal collaboration with the U.S. National Institute of Standards and Technology in Gaithersburg to compare their existing orifice flow standard with a cold atom based standard at UBC.

This work is being done in collaboration with the group of James Booth from the British Columbia Institute of Technology. Our general goals include:

  • the development of a portable and miniature laser cooling apparatus to serve as a platform for sensor development.
  • the detailed study of the physics of magneto-optic trapping.
  • the study of atom-atom and molecule-atom interactions in ultra-high vacuum for the realization of a cold atom based pressure gauge.

Associated publications

Breakthrough development: a game-changing self-calibrating quantum sensor for vacuum measurement

Self calibrating quantum sensor a game changer for vacuum measurement

Pinrui Shen, Kirk W. Madison, and James L. Booth
Realization of a universal quantum pressure standard
Metrologia []

James L. Booth, Pinrui Shen, Roman V. Krems, Kirk W. Madison
Universality of quantum diffractive collisions and the quantum pressure standard
New Journal of Physics, ||
video abstract

Kais Jooya, Nam Musterer, Kirk W. Madison, and James L. Booth
Photon-scattering-rate measurement of atoms in a magneto-optical trap
Phys. Rev. A 88, 063401 (2013)

Magnus Haw, Nathan Evetts, Will Gunton, Janelle Van Dongen, James L. Booth, and Kirk W. Madison,
Magneto-optical trap loading rate dependence on trap depth and vapor density
JOSA B, Vol. 29, Issue 3, pp. 475-483 (2012)

Janelle Van Dongen, Chenchong Zhu, Dallas Clement, Gabriel Dufour, James L. Booth, and Kirk W. Madison,
Trap-depth determination using residual gas collisions
Phys. Rev. A 84, 022708 (2011)

David E. Fagnan, Jicheng Wang, Chenchong Zhu, Pavle Djuricanin, Bruce G. Klappauf, James L. Booth, and Kirk W. Madison,
Observation of quantum diffractive collisions using shallow atomic traps
Phys. Rev. A 80, 022712 (2009) || arXiv:0907.0506

J. L. Booth, J. Van Dongen, P. Lebel, B. G. Klappauf, and K. W. Madison,
Dual-channel amplification in a single-mode diode laser for multi-isotope laser cooling
J. Opt. Soc. Am. B 24, 2914-2920 (2007)


Picture of a Rb magneto optic trap


Close up of the Rb atoms in our magneto optic trap


All the light for laser cooling 85Rb and 87Rb is generated and amplified on the “master table” and then sent by fiber optics to the experiment.