The liquid-phase xenon purification system of the XENONnT dark matter experiment

@misc{aprile2026liquidphase,
  title = {{The liquid-phase xenon purification system of the XENONnT dark matter experiment}},
  author = {E. Aprile and J. Aalbers and K. Abe and M. Abu Rmilah and M. Adrover and S. Ahmed Maouloud and L. Althueser and B. Andrieu and E. Angelino and D. Antón Martin and S. R. Armbruster and F. Arneodo and L. Baudis and M. Bazyk and V. Beligotti and L. Bellagamba and R. Biondi and K. Boese and R. M. Braun and G. Bruni and R. Budnik and C. Cai and C. Capelli and J. M. R. Cardoso and A. P. Cimental Chávez and A. P. Colijn and J. Conrad and J. J. Cuenca-García and H. Dai and V. D'Andrea and L. C. Daniel Garcia and M. P. Decowski and A. Deisting and C. Di Donato and P. Di Gangi and S. Diglio and K. Eitel and S. el Morabit and R. Elleboro and A. Elykov and A. D. Ferella and C. Ferrari and H. Fischer and T. Flehmke and M. Flierman and R. Frankel and D. Fuchs and W. Fulgione and C. Fuselli and F. Gao and R. Giacomobono and R. Glade-Beucke and L. Grandi and J. Grigat and A. Guerrero Ramos and M. Guida and P. Gyorgy and R. Hammann and C. Hils and L. Hoetzsch},
  howpublished = {arXiv},
  year = {2026},
  month = nov,
  doi = {10.48550/arxiv.2611.00093},
  eprint = {2611.00093},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2611.00093},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - The liquid-phase xenon purification system of the XENONnT dark matter experiment
AU  - E. Aprile
AU  - J. Aalbers
AU  - K. Abe
AU  - M. Abu Rmilah
AU  - M. Adrover
AU  - S. Ahmed Maouloud
AU  - L. Althueser
AU  - B. Andrieu
AU  - E. Angelino
AU  - D. Antón Martin
AU  - S. R. Armbruster
AU  - F. Arneodo
AU  - L. Baudis
AU  - M. Bazyk
AU  - V. Beligotti
AU  - L. Bellagamba
AU  - R. Biondi
AU  - K. Boese
AU  - R. M. Braun
AU  - G. Bruni
AU  - R. Budnik
AU  - C. Cai
AU  - C. Capelli
AU  - J. M. R. Cardoso
AU  - A. P. Cimental Chávez
AU  - A. P. Colijn
AU  - J. Conrad
AU  - J. J. Cuenca-García
AU  - H. Dai
AU  - V. D'Andrea
AU  - L. C. Daniel Garcia
AU  - M. P. Decowski
AU  - A. Deisting
AU  - C. Di Donato
AU  - P. Di Gangi
AU  - S. Diglio
AU  - K. Eitel
AU  - S. el Morabit
AU  - R. Elleboro
AU  - A. Elykov
AU  - A. D. Ferella
AU  - C. Ferrari
AU  - H. Fischer
AU  - T. Flehmke
AU  - M. Flierman
AU  - R. Frankel
AU  - D. Fuchs
AU  - W. Fulgione
AU  - C. Fuselli
AU  - F. Gao
AU  - R. Giacomobono
AU  - R. Glade-Beucke
AU  - L. Grandi
AU  - J. Grigat
AU  - A. Guerrero Ramos
AU  - M. Guida
AU  - P. Gyorgy
AU  - R. Hammann
AU  - C. Hils
AU  - L. Hoetzsch
PY  - 2026
DA  - 2026/11/01
PB  - arXiv
DO  - 10.48550/arxiv.2611.00093
UR  - https://arxiv.org/abs/2611.00093
AB  - The XENONnT dark matter experiment utilizes a dual-phase time projection chamber (TPC) housed in a cryostat filled with 8.5 t of ultra-pure liquid xenon. To achieve optimal sensitivity, free electrons generated by particle interactions are required to drift across the 1.5-meter detector under an electric field. Dissolved impurities, particularly oxygen (O_2), can attenuate the resulting charge signal due to electron attachment. XENONnT demands an O_2-equivalent concentration below 100 parts per trillion (ppt) to enable its dark matter sensitivity reach. A novel liquid-phase xenon purification system was developed that continuously circulates liquid xenon through custom-designed, packed-bed sorbent purifier units at a volumetric flow rate of ∼2 liters per minute (L/min) at a cryogenic temperature around 175 K. With a purification time constant of approximately 25 h, the system reached the required purity within five days. The purification strategy employs a two-step approach: For an initial cleanup, a purifier based on a copper catalyst on high-surface-area alumina support (Q5) removes impurities from the liquid xenon bulk with nearly 100% efficiency, ideal for initial detector filling or after long-term maintenance. However, the high ^222Rn emanation rate of the Q5 catalyst leads to increased background in the detector. In a second step, a purifier with sintered pellets of non-evaporable getter alloy (St707) ensures sustained purity with negligible background impact. The St707-based purifier exhibits a 55% efficiency, sufficient for normal operation. Following system commissioning, XENONnT achieved an O_2-equivalent concentration in liquid xenon below 19 ppt during its first science run. With this exceptional purity, over 86% of generated electrons survive a full drift across the TPC.
ER  -