Controlling $^{229}$Th isomeric state population in a VUV transparent crystal

Fuente: arXiv
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Main Authors: Hiraki, Takahiro, Okai, Koichi, Bartokos, Michael, Beeks, Kjeld, Fujimoto, Hiroyuki, Fukunaga, Yuta, Haba, Hiromitsu, Kasamatsu, Yoshitaka, Kitao, Shinji, Leitner, Adrian, Masuda, Takahiko, Ming, Guan, Nagasawa, Nobumoto, Ogake, Ryoichiro, Pimon, Martin, Pressler, Martin, Sasao, Noboru, Schaden, Fabian, Schumm, Thorsten, Seto, Makoto, Shigekawa, Yudai, Shimizu, Koutaro, Sikorsky, Tomas, Tamasaku, Kenji, Takatori, Sayuri, Watanabe, Tsukasa, Yamaguchi, Atsushi, Yoda, Yoshitaka, Yoshimi, Akihiro, Yoshimura, Koji
Format: Preprint
Published: 2024
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author Hiraki, Takahiro
Okai, Koichi
Bartokos, Michael
Beeks, Kjeld
Fujimoto, Hiroyuki
Fukunaga, Yuta
Haba, Hiromitsu
Kasamatsu, Yoshitaka
Kitao, Shinji
Leitner, Adrian
Masuda, Takahiko
Ming, Guan
Nagasawa, Nobumoto
Ogake, Ryoichiro
Pimon, Martin
Pressler, Martin
Sasao, Noboru
Schaden, Fabian
Schumm, Thorsten
Seto, Makoto
Shigekawa, Yudai
Shimizu, Koutaro
Sikorsky, Tomas
Tamasaku, Kenji
Takatori, Sayuri
Watanabe, Tsukasa
Yamaguchi, Atsushi
Yoda, Yoshitaka
Yoshimi, Akihiro
Yoshimura, Koji
author_facet Hiraki, Takahiro
Okai, Koichi
Bartokos, Michael
Beeks, Kjeld
Fujimoto, Hiroyuki
Fukunaga, Yuta
Haba, Hiromitsu
Kasamatsu, Yoshitaka
Kitao, Shinji
Leitner, Adrian
Masuda, Takahiko
Ming, Guan
Nagasawa, Nobumoto
Ogake, Ryoichiro
Pimon, Martin
Pressler, Martin
Sasao, Noboru
Schaden, Fabian
Schumm, Thorsten
Seto, Makoto
Shigekawa, Yudai
Shimizu, Koutaro
Sikorsky, Tomas
Tamasaku, Kenji
Takatori, Sayuri
Watanabe, Tsukasa
Yamaguchi, Atsushi
Yoda, Yoshitaka
Yoshimi, Akihiro
Yoshimura, Koji
contents The radioisotope Th-229 is renowned for its extraordinarily low-energy, long-lived nuclear first-excited state. This isomeric state can be excited by VUV lasers and the transition from the ground state has been proposed as a reference transition for ultra-precise nuclear clocks. Such nuclear clocks will find multiple applications, ranging from fundamental physics studies to practical implementations. Recent investigations extracted valuable constraints on the nuclear transition energy and lifetime, populating the isomer in stochastic nuclear decay of U-233 or Ac-229. However, to assess the feasibility and performance of the (solid-state) nuclear clock concept, time-controlled excitation and depopulation of the $^{229}$Th isomer together with time-resolved monitoring of the radiative decay are imperative. Here we report the population of the $^{229}$Th isomeric state through resonant X-ray pumping and detection of the radiative decay in a VUV transparent $^{229}$Th-doped CaF$_2$ crystal. The decay half-life is measured to $447\pm 25$ s, with a transition wavelength of $148.18 \pm 0.42$ nm and a radiative decay fraction consistent with unity. Furthermore, we report a new ``X-ray quenching'' effect which allows to de-populate the isomer on demand and effectively reduce the half-life by at least a factor 50. Such controlled quenching can be used to significantly speed up the interrogation cycle in future nuclear clock schemes. Our results show that full control over the $^{229}$Th nuclear isomer population can be achieved in a crystal environment. In particular, non-radiative decay processes that might lead to a broadening of the isomer transition linewidth are negligible, paving the way for the development of a compact and robust solid-state nuclear clock. Further studies are needed to reveal the underlying physical mechanism of the X-ray quenching effect.
format Preprint
id arxiv_https___arxiv_org_abs_2405_09577
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Controlling $^{229}$Th isomeric state population in a VUV transparent crystal
Hiraki, Takahiro
Okai, Koichi
Bartokos, Michael
Beeks, Kjeld
Fujimoto, Hiroyuki
Fukunaga, Yuta
Haba, Hiromitsu
Kasamatsu, Yoshitaka
Kitao, Shinji
Leitner, Adrian
Masuda, Takahiko
Ming, Guan
Nagasawa, Nobumoto
Ogake, Ryoichiro
Pimon, Martin
Pressler, Martin
Sasao, Noboru
Schaden, Fabian
Schumm, Thorsten
Seto, Makoto
Shigekawa, Yudai
Shimizu, Koutaro
Sikorsky, Tomas
Tamasaku, Kenji
Takatori, Sayuri
Watanabe, Tsukasa
Yamaguchi, Atsushi
Yoda, Yoshitaka
Yoshimi, Akihiro
Yoshimura, Koji
Nuclear Experiment
Atomic Physics
The radioisotope Th-229 is renowned for its extraordinarily low-energy, long-lived nuclear first-excited state. This isomeric state can be excited by VUV lasers and the transition from the ground state has been proposed as a reference transition for ultra-precise nuclear clocks. Such nuclear clocks will find multiple applications, ranging from fundamental physics studies to practical implementations. Recent investigations extracted valuable constraints on the nuclear transition energy and lifetime, populating the isomer in stochastic nuclear decay of U-233 or Ac-229. However, to assess the feasibility and performance of the (solid-state) nuclear clock concept, time-controlled excitation and depopulation of the $^{229}$Th isomer together with time-resolved monitoring of the radiative decay are imperative. Here we report the population of the $^{229}$Th isomeric state through resonant X-ray pumping and detection of the radiative decay in a VUV transparent $^{229}$Th-doped CaF$_2$ crystal. The decay half-life is measured to $447\pm 25$ s, with a transition wavelength of $148.18 \pm 0.42$ nm and a radiative decay fraction consistent with unity. Furthermore, we report a new ``X-ray quenching'' effect which allows to de-populate the isomer on demand and effectively reduce the half-life by at least a factor 50. Such controlled quenching can be used to significantly speed up the interrogation cycle in future nuclear clock schemes. Our results show that full control over the $^{229}$Th nuclear isomer population can be achieved in a crystal environment. In particular, non-radiative decay processes that might lead to a broadening of the isomer transition linewidth are negligible, paving the way for the development of a compact and robust solid-state nuclear clock. Further studies are needed to reveal the underlying physical mechanism of the X-ray quenching effect.
title Controlling $^{229}$Th isomeric state population in a VUV transparent crystal
topic Nuclear Experiment
Atomic Physics
url https://arxiv.org/abs/2405.09577