Status of the NEXT project LIOR ARAZI BENGURION

Status of the NEXT project LIOR ARAZI BEN-GURION UNIVERSITY ON BEHALF OF THE NEXT COLLABORATION 15 th Vienna Conference on Instrumentation 18 -23 February 2019, Vienna

February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 2

Q-value shared among 4 particles February 19, 2019 Electrons kinetic energy = Q-value LIOR ARAZI (BGU): NEXT STATUS 3

counts Total electron kinetic energy February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 4

February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 5

NEXT Neutrino Experiment with Xenon TPC February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 6

NEXT Concept -8 k. V -30 k. V S 2 magnitude by proportional EL (PMTs) gives the event energy S 2 time-slice images (Si. PMs) give the event topology February 19, 2019 EL (S 2) e- Primary scintillation (S 1) LIOR ARAZI (BGU): NEXT STATUS 7

Energy resolution in Xe gas A. Bolotnikov, B. Ramsey, Nucl. Instr. and Meth. A 396 (1997) 360 NEXT February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 8

Topological signature Bragg peak – ‘blob’ of dense ionization at the end of electron track GEANT 4 February 19, 2019 2 blobs LIOR ARAZI (BGU): NEXT STATUS 1 blob 9

Blob-based background rejection P. Ferrario, et al. (NEXT Collaboration), JHEP 1605 (2016) 159, ar. Xiv: 1507. 05902 February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 10

Running prototype: NEXT-White (NEW) ~10 kg Xe F. Monrabal et al. (NEXT collaboration), ar. Xiv: 1804. 02409 February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 11

Running prototype: NEXT-White (NEW) - 10 kg Xe February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 12

Online 3 D calibration maps with 83 m. Kr: pointlike 41. 5 ke. V events throughout TPC volume Geometrical S 2 map Electron lifetime map Average >4 ms, 8 times larger than max drift time G. Martínez-Lema, et al. (NEXT collaboration) 2018 JINST 13 P 10014, ar. Xiv: 1804. 01780. February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 13

NEW: Calibration with “high-energy” sources February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 14

J. Renner et al. (NEXT collaboration), 2018 JINST 13 P 10020, ar. Xiv: 1808. 01804. February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 15

Track topology in NEW Beta emission from the cathode P. Novella, et al. (NEXT collaboration) JHEP 1810 (2018) 112, ar. Xiv: 1804. 00471 February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 16

Signal/background discrimination using blobs 208 Tl escape peak events: MC and data February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 17

February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS Inner lead castle Radon-free air NEW: low-background run < 3 m. Hz above 600 ke. V 18

Low background: sources are well understood and modelled Data vs. expectation from nominal background model February 19, 2019 Expectation from best-fit to data with isotope-specific scaling LIOR ARAZI (BGU): NEXT STATUS 19

RGA spectrum confirms Xe enriched to 90% 136 Xe… Enriched Xe run began Feb 7 February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 20

NEXT-100 (assembly in one year) Pressure vessel: St-St, rated for 15 bar TPC: 100 kg active region, 130 cm drift length Tracking plane: 3000 Si. PMs, 15 mm pitch Energy plane: 60 radio-pure PMTs, 30% coverage Inner shield: 12 cm Cu Outer shield: lead castle with Rn-free air February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 21

NEXT-100 expected sensitivity Background: 1 counts/100 kg/yr for 1% FWHM Dashed: largest and smallest estimations for the nuclear matrix elements Similar sensitivity as Kam. Land-ZEN after ~4 years (remember NEXT-100 is a demonstrator for a ton-scale detector) J. Martín-Albo, et al. (NEXT collaboration), JHEP (2016) 2016 159, ar. Xiv: 1511. 09246 February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 22

NEXT on the ton-scale: Exploring the Inverted Hierarchy IH J. Martín-Albo Ph. D. thesis (2015), http: //roderic. uv. es/handle/10550/41728 February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 23

Barium Tagging: towards “background free” experiment A. D. Mc. Donald et al. (NEXT Collaboration), PRL 120, 132504 (2018) February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 24

“Conventional” R&D Parallel to Ba-tagging, additional strategies under development for background reduction Two main problems to tackle: ◦ Electron diffusion smears out track features ◦ PMTs at the energy plane still contribute radioactive background Strategies: ◦ Low-diffusion gas (Xe-He, or Xe doped with <1% CH 4) ◦ Cryogenic operation to allow energy measurement with radiopure Si. PMs February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 25

Electron diffusion in pure Xe: from “spaghetti with meatballs” to “sea cucumber” Original track 1 m diffusion in pure Xe Diffusion driven by elastic collisions with heavy xenon atoms February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 26

Electron diffusion in Xe-He, or Xe with <1% methane Original track 1 m diffusion in Xe-He (80/20), or Xe with <1% CH 4 Diffusion dominated by elastic collisions with the much lighter He atoms, or by inelastic collisions with CH 4 R. Felkai, et al. (NEXT collaboration) Nucl. Instrum. Meth. A 905 (2018) 82, ar. Xiv: 1710. 05600 C. A. O. Henriques, et al. (NEXT collaboration), JHEP 1901 (2019) 027, ar. Xiv: 1806. 05891. February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 27

Summary and outlook February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 28

Backup slides February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 29

February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 30

Kam. Land-Zen + EXO-200 2015 data February 19, 2019 LIOR ARAZI (BGU): NEXT STATUS 31