Home

The Slow Positron Beam in Israel (SPOT-IL) and Graphene-Based Positron Charge Sensors


  Paz Or  ,  Dan Cohen [1]  ,  Gilad Erlichman [1]  ,  Eli Piasetzky [2]  ,  Iris Sabo-Napadensky [3]  ,  Hadar Steinberg [1]  ,  Sharon May-Tal Beck [4]  ,  Guy Ron [1]  
 [1] Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem, Israel 91904
[2] School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv, Israel 69978
[3] Soreq NRC, Yavne, Israel 81800
[4] NRCN, P.O.Box 9001, Beer-Sheva, Israel 84190

In the past few years, progress has been made in our group with the development of graphene-based positron charge sensors1. These sensors will be used for the measurements of positrons interactions with solids. Positrons mobility could be measured directly by the localization of annihilation events inside the solid. For that purpose, and for other basic and applied research, a slow positron beam was built at the Hebrew University2. The beam follows a traditional design3, using a 22Na source4, of about ~1.5 GBq (40 mCi), a Tungsten moderator and a unique grounded target cell, with positrons energy that can vary between 0.03 keV and 30 keV. The detection system is comprised of two High Purity Germanium detectors, facing each other, for low background Doppler Broadening (DB) measurements. Data readout is done by a compact desktop system with two independent 16k digital multichannel analyzers5. The target cell is designed to allow a combined measurement of sample conductivity and DB, with the flexibility to add more detection options in the future. The beam was successfully tested on a Fe Target, in various energies and is now operational and available for research.

1.     

Or, P., et al. "Graphene-based positron charge sensor." Applied Physics Letters 113.15 (2018): 154101; https://doi.org/10.1063/1.5053477

2.     

Or, P., et al. "SPOT IL-Slow positron facility in Israel." AIP Conference Proceedings. Vol. 2182. No. 1. AIP Publishing, 2019; https://doi.org/10.1063/1.5135841

3.     

Anwand, Wolfgang, et al. “Design and Construction of a Slow Positron Beam for Solid and Surface Investigations.” Defect and Diffusion Forum, vol. 331, Trans Tech Publications, Ltd., Sept. 2012, pp. 25–40; https://doi.org/10.4028/www.scientific.net/ddf.331.25.

4.     

http://positron.physik.uni-halle.de/source.html

5.     

https://www.caen.it/products/dt5780/