The NEXT-100 Detector

The NEXT collaboration is dedicated to the study of double beta decays of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mrow></mml:mrow> <mml:mrow></mml:mrow> <mml:mn>136</mml:mn></mml:mmultiscripts> </mml:math> Xe using a high-pressure gas electroluminescent time projection chamber. This advanced technology combines exceptional energy resolution ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo>≤</mml:mo> <mml:mn>1</mml:mn> <mml:mo>%</mml:mo></mml:mrow> </mml:math> FWHM at the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>Q</mml:mi> <mml:mrow><mml:mi>β</mml:mi> <mml:mi>β</mml:mi></mml:mrow> </mml:msub> </mml:math> value of the neutrinoless double beta decay) and powerful topological event discrimination. Building on the achievements of the NEXT-White detector, the NEXT-100 detector started taking data at the Laboratorio Subterráneo de Canfranc (LSC) in May of 2024. Designed to operate with xenon gas at 13.5 bar, NEXT-100 consists of a time projection chamber where the energy and the spatial pattern of the ionising particles in the detector are precisely retrieved using two sensor planes (one with photo-multiplier tubes and the other with silicon photo-multipliers). The detector has been operating at stable conditions using argon and xenon gases at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mo>∼</mml:mo></mml:math> 4 bar and drift fields of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>74</mml:mn> <mml:mspace></mml:mspace> <mml:mtext>V</mml:mtext> <mml:mspace></mml:mspace> <mml:msup><mml:mtext>cm</mml:mtext> <mml:mrow><mml:mo>-</mml:mo> <mml:mn>1</mml:mn></mml:mrow> </mml:msup> </mml:mrow> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>118</mml:mn> <mml:mspace></mml:mspace> <mml:mtext>V</mml:mtext> <mml:mspace></mml:mspace> <mml:msup><mml:mtext>cm</mml:mtext> <mml:mrow><mml:mo>-</mml:mo> <mml:mn>1</mml:mn></mml:mrow> </mml:msup> </mml:mrow> </mml:math> , respectively. Alpha decays from the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mrow></mml:mrow> <mml:mrow></mml:mrow> <mml:mn>222</mml:mn></mml:mmultiscripts> </mml:math> Rn chain have been used to test and monitor the stability of the detector, showing a constant electron lifetime in the drift volume. In this paper, in addition to reporting the results of the commissioning run, we provide a detailed description of the NEXT-100 detector, describe its assembly, and present the current estimation of the radiopurity budget.