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Towards Low-Energy Electron High-Resolution Spectroscopy with Transition-Edge Sensors

R. Ammendola, A. Apponi, G. Benato, M. G. Betti, R. Biondi, P. Bos, M. Cadeddu, A. Casale, O. Castellano, G. Cavoto, L. Cecchini, E. Celasco, M. Chirico, W. Chung, A. G. Cocco, A. P. Colijn, B. Corcione, N. D'Ambrosio, M. D'Incecco, G. De Bellis, M. De Deo, N. de Groot, A. Esposito, M. Farino, S. Farinon, A. D. Ferella, L. Ferro, L. Ficcadenti, G. Galbato Muscio, S. Gariazzo, H. Garrone, F. Gatti, F. Malnati, G. Mangano, L. E. Marcucci, C. Mariani, J. Mead, G. Menichetti, M. Messina, E. Monticone, M. Naafs, S. Nagorny, V. Narcisi, F. Pandolfi, R. Pavarani, C. Pepe, C. Perez de los Heros, O. Pisanti, F. M. Pofi, A. D. Polosa, I. Rago, M. Rajteri, S. Ritarossi, N. Rossi, A. Ruocco, G. Salina, A. Santucci, M. Sestu, A. Tan, V. Tozzini, C. G. Tully, I. van Rens, F. Virzi, G. Visser, M. Viviani

Abstract

We present a study of the energy resolution of transition-edge sensors (TESs) for the detection of electrons in the 100 eV kinetic energy range. The TES is a Ti-Au bilayer with an active area of $(60 \times 60)$ $μ\text{m}^2$ and a critical temperature of $\sim$ 80 mK. The electron source is based on vertically-aligned multiwall carbon nanotubes located inside the cryostat, with electrons generated via field emission. For electrons in the (92 - 99) eV kinetic energy range, we obtain a Gaussian energy resolution for fully-absorbed electrons of (0.479 $\pm$ 0.041 $\pm$ 0.055) eV. When considering the full-width at half-maximum of the peak, the corresponding resolution is of (1.44 $\pm$ 0.17 $\pm$ 0.27) eV. The former represents an improvement of (46 - 60)% with respect to previous results, and is mainly attributed to the reduction in the TES active area. The latter is instead an improvement of over a factor of 20, and is mainly due to the reduction in the emitting area of the electron source, which significantly suppresses electron back-scattering in proximity of the TES. These results represent a major milestone toward high-precision spectroscopy on low-energy electrons, which is a key objective for the PTOLEMY experiment.

Towards Low-Energy Electron High-Resolution Spectroscopy with Transition-Edge Sensors

Abstract

We present a study of the energy resolution of transition-edge sensors (TESs) for the detection of electrons in the 100 eV kinetic energy range. The TES is a Ti-Au bilayer with an active area of and a critical temperature of 80 mK. The electron source is based on vertically-aligned multiwall carbon nanotubes located inside the cryostat, with electrons generated via field emission. For electrons in the (92 - 99) eV kinetic energy range, we obtain a Gaussian energy resolution for fully-absorbed electrons of (0.479 0.041 0.055) eV. When considering the full-width at half-maximum of the peak, the corresponding resolution is of (1.44 0.17 0.27) eV. The former represents an improvement of (46 - 60)% with respect to previous results, and is mainly attributed to the reduction in the TES active area. The latter is instead an improvement of over a factor of 20, and is mainly due to the reduction in the emitting area of the electron source, which significantly suppresses electron back-scattering in proximity of the TES. These results represent a major milestone toward high-precision spectroscopy on low-energy electrons, which is a key objective for the PTOLEMY experiment.
Paper Structure (5 sections, 1 equation, 4 figures, 1 table)

This paper contains 5 sections, 1 equation, 4 figures, 1 table.

Table of Contents

  1. Introduction
  2. Experimental Setup
  3. Data Analysis
  4. Conclusions
  5. Acknowledgements

Figures (4)

  • Figure 1: Signal amplitude spectrum for 96-eV electrons (red histogram), compared to the same spectrum obtained in the previous measurement articolo(black histogram in the inset).
  • Figure 2: Example fits of the electron absorption peaks: the green data corresponds to electrons with a kinetic energy $E_{\text{e}} = 93$ eV, the black data to $E_{\text{e}} = 99$ eV.
  • Figure 3: Top: TES Gaussian energy resolution $\Delta E_\text{gaus}$ for electrons, as a function of their kinetic energy $E_{\text{e}}$. Bottom: TES full-width at half-maximum energy resolution $\Delta E_\text{fwhm}$ for electrons, as a function of their kinetic energy $E_{\text{e}}$.
  • Figure 4: Joule power $P_\text{J}$ needed to bring the TES to its working point for different values of $V_\text{CNT}$, normalized to the Joule power needed for the lowest $V_\text{CNT}$ value. A black dashed line corresponding to unity is plotted to guide the eye.