eprintid: 1501130 rev_number: 24 eprint_status: archive userid: 608 dir: disk0/01/50/11/30 datestamp: 2016-06-23 14:07:56 lastmod: 2021-11-29 00:47:56 status_changed: 2016-06-23 14:07:56 type: article metadata_visibility: show creators_name: Bardon, T creators_name: May, RK creators_name: Taday, PF creators_name: Strlic, M title: Influence of Particle Size on Optical Constants From Pellets Measured With Terahertz Pulsed Spectroscopy ispublished: pub divisions: UCL divisions: B04 divisions: C04 divisions: F34 note: This work is licensed under a Creative Commons Attribution 3.0 License. For more information, see http://creativecommons.org/licenses/by/3.0/ abstract: Particle size is shown to influence both the overall value and the measurement precision of the refractive index and absorption coefficient of a sample diluted with high density polyethylene (HDPE) powder and compressed in a pellet. However, excessive grinding of a sample before it is mixed with HDPE powder can result in the formation of large particle clusters. These aggregates can induce internal scattering of the terahertz pulse within the pellet as well as lead to different mechanical properties of the pellet, which may change the distribution of air pores. These phenomena result in extracted optical constants with low accuracy and precision. The present work introduces a simple experimental procedure to improve the precision and accuracy of optical constants from spectroscopic pellets. This procedure consists of moderately grinding the sample powder in fine HDPE powder with a pestle and mortar. The standard deviation of the refractive index of Prussian blue has been observed to reduce from 0.14 to 0.02 following this procedure. date: 2016-05-01 date_type: published official_url: http://dx.doi.org/10.1109/TTHZ.2016.2538641 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1137865 doi: 10.1109/TTHZ.2016.2538641 lyricists_name: Bardon, Tiphaine lyricists_name: Strlic, Matija lyricists_id: TBARD20 lyricists_id: MSTRL90 actors_name: Bardon, Tiphaine actors_name: Barczynska, Patrycja actors_id: TBARD20 actors_id: PBARC91 actors_role: owner actors_role: impersonator full_text_status: public publication: IEEE Transactions on Terahertz Science and Technology volume: 6 number: 3 pagerange: 408-413 issn: 2156-3446 citation: Bardon, T; May, RK; Taday, PF; Strlic, M; (2016) Influence of Particle Size on Optical Constants From Pellets Measured With Terahertz Pulsed Spectroscopy. IEEE Transactions on Terahertz Science and Technology , 6 (3) pp. 408-413. 10.1109/TTHZ.2016.2538641 <https://doi.org/10.1109/TTHZ.2016.2538641>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/1501130/1/07454766.pdf