Leiden University Student Repository

Otterloo, Daan van (2017)

High energy photon detection using a NbNsuperconducting single photon detector

Bachelor thesis | Natuurkunde (BSc)

We measure the temperature dependent resistance of a niobium nitride (NbN) from room temperature to 4 K. The increasing resistance with decreasing temperature can be explained by tunneling of electrons between grain boundaries. Once the detector is in the superconducting regime single photon counts can be registered. We find an optimal setting of the trigger level of 0.2 V to register detection events while minimizing the influence of amplifier noise. From the measured voltage pulses we estimate a kinetic inductance of 200 nH for our devices. We explore the regime of high photon energies by plotting the count rate vs optical power on a double logarithmic scale. For photons with 500 nm wavelength the highest initial slope is equal to 2.6, indicating that detector tomography with 3 photon events realistic. Unfortunately, higher slopes are not observed and makes looking into detection events with more than 10 eV total energy difficult if not impossible

superconductors

single photon detection

tomography

Author

Otterloo, Daan van

Faculty

Faculty of Science

Supervisors

Dood, Michiel de

ECTS Credits

3

Language

en