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cupid_pub:the_cupid_experiment [2021/05/22 20:12]
benato old revision restored (2021/05/22 14:19)
cupid_pub:the_cupid_experiment [2021/06/04 08:31] (current)
benato [The Experiment]
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 |{{ cupid_pub:​double_beta.png?​330 }} |{{ cupid_pub:​screenshot_20210522_144702.jpeg?​330 }}| |{{ cupid_pub:​double_beta.png?​330 }} |{{ cupid_pub:​screenshot_20210522_144702.jpeg?​330 }}|
-|Decay scheme of 2νββ (top) and 0νββ decay (bottom). The two processes share the same parent and daughter nucleus, but differ for the number of emitted ​partiles, and consequently their energy.|The measurable sum electron spectrum is a continuum for 2νββ decay, and an excess at Q<​sub>​ββ</​sub>​ for 0νββ decay.|+|Decay scheme of 2νββ (top) and 0νββ decay (bottom). The two processes share the same parent and daughter nucleus, but differ for the number of emitted ​particles, and consequently their energy.|The measurable sum electron spectrum is a continuum for 2νββ decay, and an excess at Q<​sub>​ββ</​sub>​ for 0νββ decay.|
  
  
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 Thus, CUPID will not only change the crystal, but also the candidate isotope. The reason for this choice is twofold: Thus, CUPID will not only change the crystal, but also the candidate isotope. The reason for this choice is twofold:
 on the one hand, Li<​sub>​2 </​sub>​MoO<​sub>​4</​sub>​ is a scintillating material with a particle-dependent light yield, on the one hand, Li<​sub>​2 </​sub>​MoO<​sub>​4</​sub>​ is a scintillating material with a particle-dependent light yield,
-on the other hand the candidate ​isotpe ​<​sup>​100</​sup>​Mo has a Q-value of 3034 keV+on the other hand the candidate ​isotope ​<​sup>​100</​sup>​Mo has a Q-value of 3034 keV
 (compared to 2527 keV of <​sup>​130</​sup>​Te),​ which lies above most of the γ background from environmental radioactivity. Special attention is paid to the minimization of the radioactive contamination levels of all employed materials. Using the information from the predecessor experiments CUORE, [[https://​cupid-0.lngs.infn.it/​|CUPID-0]],​ and [[https://​cupid-mo.mit.edu|CUPID-Mo]],​ the projected background at Q<​sub>​ββ</​sub>​ is expected to be at the level of 10<​sup>​-4</​sup>​ counts/​keV/​kg/​yr. (compared to 2527 keV of <​sup>​130</​sup>​Te),​ which lies above most of the γ background from environmental radioactivity. Special attention is paid to the minimization of the radioactive contamination levels of all employed materials. Using the information from the predecessor experiments CUORE, [[https://​cupid-0.lngs.infn.it/​|CUPID-0]],​ and [[https://​cupid-mo.mit.edu|CUPID-Mo]],​ the projected background at Q<​sub>​ββ</​sub>​ is expected to be at the level of 10<​sup>​-4</​sup>​ counts/​keV/​kg/​yr.
- +CUPID-Mo ​ has  robustly ​ demonstrated ​ that Li<​sub>​2</​sub>​MoO<​sub>​4</​sub>​ scintillating bolometers 
 +meet the requirement for CUPID. CUPID-Mo was an array of 20 elements that took data until 2020 in the Modane underground laboratory in France, as a follow-up ​ of  the LUMINEU ​ project. 
 +It  has shown  the  maturity ​ reached ​ by  the proposed CUPID  technology ​ and  the  high  standard ​ of the Li<​sub>​2</​sub>​MoO<​sub>​4</​sub>​ detectors ​ in  terms  of  energy resolution, α/β rejection capabilities,​ internal radiopurity,​ and overall reproducibility of the results.
  
  
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-==== The Detector ==== +===== The Detector =====
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-The CUPID crystals are operated as cryogenic calorimeters,​ each equipped with a cryogenic light detector. A particle interaction in the crystal produces a phonon ​ and light signal (see figure below), the latter one is used to discriminate ​ α background from the electrons events.  +
-{{ :​cupid_pub:​cupid_detector.png?​450 |}} +
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 +In CUPID, the Li<​sub>​2</​sub>​MoO<​sub>​4</​sub>​ crystals are operated as cryogenic calorimeters,​ and coupled to a light detector. The light detectors are germanium wafers, and are also instrumented as calorimeters.
 +A particle interaction in the crystal produces phonons and scintillation light.
 +The heat from recombining phonons is read by a Neutron Transmutation Doped (NTD) germanium thermistor
 +glued to the crystal. The light escapes the crystal, inducing a phonon signal in the light detector, which is also read by an NTD.
  
 +|{{ cupid_pub:​cupid_detector.png?​350 }}|{{cupid_pub:​screenshot_20210522_221509.jpeg?​450}}|
 +|Schematic of a cryogenic calorimeter,​ with the heat channel (blue) and a light detector (gray).|Installation of crystals for a CUPID test run. A light detector is visible in the bottom right.|
Last modified: le 2021/05/22 20:12