Characterization of inverted coaxial [Formula: see text] Ge detectors in GERDA for future double- [Formula: see text] decay experiments

M Agostini; G Araujo; A M Bakalyarov; M Balata; I Barabanov; L Baudis; C Bauer; E Bellotti; S Belogurov; A Bettini; L Bezrukov; V Biancacci; E Bossio; V Bothe; V Brudanin; R Brugnera; A Caldwell; C Cattadori; A Chernogorov; T Comellato; V D'Andrea; E V Demidova; N Di Marco; E Doroshkevich; F Fischer; M Fomina; A Gangapshev; A Garfagnini; C Gooch; P Grabmayr; V Gurentsov; K Gusev; J Hakenmüller; S Hemmer; W Hofmann; J Huang; M Hult; L V Inzhechik; J Janicskó Csáthy; J Jochum; M Junker; V Kazalov; Y Kermaïdic; H Khushbakht; T Kihm; I V Kirpichnikov; A Klimenko; R Kneißl; K T Knöpfle; O Kochetov; V N Kornoukhov; P Krause; V V Kuzminov; M Laubenstein; M Lindner; I Lippi; A Lubashevskiy; B Lubsandorzhiev; G Lutter; C Macolino; B Majorovits; W Maneschg; L Manzanillas; M Miloradovic; R Mingazheva; M Misiaszek; P Moseev; Y Müller; I Nemchenok; L Pandola; K Pelczar; L Pertoldi; P Piseri; A Pullia; C Ransom; L Rauscher; S Riboldi; N Rumyantseva; C Sada; F Salamida; S Schönert; J Schreiner; M Schütt; A-K Schütz; O Schulz; M Schwarz; B Schwingenheuer; O Selivanenko; E Shevchik; M Shirchenko; L Shtembari; H Simgen; A Smolnikov; D Stukov; A A Vasenko; A Veresnikova; C Vignoli; K von Sturm; T Wester; C Wiesinger; M Wojcik; E Yanovich; B Zatschler; I Zhitnikov; S V Zhukov; D Zinatulina; A Zschocke; A J Zsigmond; K Zuber; G Zuzel; Gerda Collaboration

doi:10.1140/epjc/s10052-021-09184-8

Characterization of inverted coaxial $^{76}$ Ge detectors in GERDA for future double- $β$ decay experiments

Eur Phys J C Part Fields. 2021;81(6):505. doi: 10.1140/epjc/s10052-021-09184-8. Epub 2021 Jun 7.

Authors

M Agostini^{1

2}, G Araujo³, A M Bakalyarov⁴, M Balata⁵, I Barabanov⁶, L Baudis³, C Bauer⁷, E Bellotti^{8

9}, S Belogurov^{6

10

11}, A Bettini^{12

13}, L Bezrukov⁶, V Biancacci^{12

13}, E Bossio², V Bothe⁷, V Brudanin¹⁴, R Brugnera^{12

13}, A Caldwell¹⁵, C Cattadori⁹, A Chernogorov^{10

4}, T Comellato², V D'Andrea¹⁶, E V Demidova¹⁰, N Di Marco⁵, E Doroshkevich⁶, F Fischer¹⁵, M Fomina¹⁴, A Gangapshev^{7

6}, A Garfagnini^{12

13}, C Gooch¹⁵, P Grabmayr¹⁷, V Gurentsov⁶, K Gusev^{14

4

2}, J Hakenmüller⁷, S Hemmer¹³, W Hofmann⁷, J Huang³, M Hult¹⁸, L V Inzhechik^{6

19}, J Janicskó Csáthy^{2

20}, J Jochum¹⁷, M Junker⁵, V Kazalov⁶, Y Kermaïdic⁷, H Khushbakht¹⁷, T Kihm⁷, I V Kirpichnikov¹⁰, A Klimenko^{14

7

21}, R Kneißl¹⁵, K T Knöpfle⁷, O Kochetov¹⁴, V N Kornoukhov^{6

11}, P Krause², V V Kuzminov⁶, M Laubenstein⁵, M Lindner⁷, I Lippi¹³, A Lubashevskiy¹⁴, B Lubsandorzhiev⁶, G Lutter¹⁸, C Macolino¹⁶, B Majorovits¹⁵, W Maneschg⁷, L Manzanillas¹⁵, M Miloradovic³, R Mingazheva³, M Misiaszek²², P Moseev⁶, Y Müller³, I Nemchenok^{14

21}, L Pandola²³, K Pelczar^{22

18}, L Pertoldi^{12

13}, P Piseri²⁴, A Pullia²⁴, C Ransom³, L Rauscher¹⁷, S Riboldi²⁴, N Rumyantseva^{14

4}, C Sada^{12

13}, F Salamida¹⁶, S Schönert², J Schreiner⁷, M Schütt⁷, A-K Schütz¹⁷, O Schulz¹⁵, M Schwarz², B Schwingenheuer⁷, O Selivanenko⁶, E Shevchik¹⁴, M Shirchenko¹⁴, L Shtembari¹⁵, H Simgen⁷, A Smolnikov^{14

7}, D Stukov⁴, A A Vasenko¹⁰, A Veresnikova⁶, C Vignoli⁵, K von Sturm^{12

13}, T Wester²⁵, C Wiesinger², M Wojcik²², E Yanovich⁶, B Zatschler²⁵, I Zhitnikov¹⁴, S V Zhukov⁴, D Zinatulina¹⁴, A Zschocke¹⁷, A J Zsigmond¹⁵, K Zuber²⁵, G Zuzel²²; Gerda Collaboration

Affiliations

¹ Department of Physics and Astronomy, University College London, London, UK.
² Physik Department, Technische Universität München, Munich, Germany.
³ Physik-Institut, Universität Zürich, Zurich, Switzerland.
⁴ National Research Centre "Kurchatov Institute", Moscow, Russia.
⁵ INFN Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, Assergi, Italy.
⁶ Institute for Nuclear Research of the Russian Academy of Sciences, Moscow, Russia.
⁷ Max-Planck-Institut für Kernphysik, Heidelberg, Germany.
⁸ Dipartimento di Fisica, Università Milano Bicocca, Milan, Italy.
⁹ INFN Milano Bicocca, Milan, Italy.
¹⁰ Institute for Theoretical and Experimental Physics, NRC "Kurchatov Institute", Moscow, Russia.
¹¹ NRNU MEPhI, Moscow, Russia.
¹² Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, Padua, Italy.
¹³ INFN Padova, Padua, Italy.
¹⁴ Joint Institute for Nuclear Research, Dubna, Russia.
¹⁵ Max-Planck-Institut für Physik, Munich, Germany.
¹⁶ INFN Laboratori Nazionali del Gran Sasso and Università degli Studi dell'Aquila, L'Aquila, Italy.
¹⁷ Physikalisches Institut, Eberhard Karls Universität Tübingen, Tübingen, Germany.
¹⁸ European Commission, JRC-Geel, Geel, Belgium.
¹⁹ Moscow Institute of Physics and Technology, Moscow, Russia.
²⁰ Leibniz-Institut für Kristallzüchtung, Berlin, Germany.
²¹ Dubna State University, Dubna, Russia.
²² Institute of Physics, Jagiellonian University, Cracow, Poland.
²³ INFN Laboratori Nazionali del Sud, Catania, Italy.
²⁴ Dipartimento di Fisica, Università degli Studi di Milano and INFN Milano, Milan, Italy.
²⁵ Institut für Kern- und Teilchenphysik, Technische Universität Dresden, Dresden, Germany.

Abstract

Neutrinoless double- $β$ decay of $^{76}$ Ge is searched for with germanium detectors where source and detector of the decay are identical. For the success of future experiments it is important to increase the mass of the detectors. We report here on the characterization and testing of five prototype detectors manufactured in inverted coaxial (IC) geometry from material enriched to 88% in $^{76}$ Ge. IC detectors combine the large mass of the traditional semi-coaxial Ge detectors with the superior resolution and pulse shape discrimination power of point contact detectors which exhibited so far much lower mass. Their performance has been found to be satisfactory both when operated in vacuum cryostat and bare in liquid argon within the Gerda setup. The measured resolutions at the Q-value for double- $β$ decay of $^{76}$ Ge ( $Q_{β β}$ = 2039 keV) are about 2.1 keV full width at half maximum in vacuum cryostat. After 18 months of operation within the ultra-low background environment of the GERmanium Detector Array (Gerda) experiment and an accumulated exposure of 8.5 kg $\cdot$ year, the background index after analysis cuts is measured to be $4 . 9_{- 3.4}^{+ 7.3} \times 10^{- 4} counts / (keV \cdot kg \cdot year)$ around $Q_{β β}$ . This work confirms the feasibility of IC detectors for the next-generation experiment Legend.