GEANT4 rendering of the EDELWEISS cryostat and the detectors. Experimen Due to their small size they have small hea The muon signals are very large and are affected by non-linearities of the TES We fit the muon pulse using a thermal model and extract thermal parameters that affect energy resolution. Development of transition-edge sensor based large area photon detectors for CUPID Vivek Singh, UC Berkeley Neutrino - 2020 (Poster # 97) CUPID: CUORE Upgrade with Particle ID Transition-edge sensors for photon detectors Next generation bolometric search for 0𝜈𝛽𝛽 experiment. CUPID pre-CDR (arXiv:1907.09376) Detector performance V Singh 1, W Armstrong 2, G Benato 1, 3, M Beretta 1, C L Chang 4,5 , B K Fujikawa 3, K Hafidi 2, E Hansen 1, R Huang 1, G Karapetrov 6, Yu Kolomensky 1, 3, M Lisovenko 7,8, L Marini 1, Z Meziani 2, J Pearson 7, T Polakovic 2,6, B Schmidt 3, V Novosad 2,7, K J Vetter 1, S Wagaarachchi 1, G Wang 4, B Welliver 3, V Yefremenko 4, J Zhang 4 1 Department of Physics, University of California, Berkeley, Berkeley, CA. 2 Physics Division, Argonne National Laboratory, Chicago, IL. 3 Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA. 4 High Energy Physics Division, Argonne National Laboratory, Chicago, IL. 5 Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL. 6 Department of Physics, Drexel University, Philadelphia, PA. 7 Materials Science Division, Argonne National Laboratory, Chicago, IL. 8Nanoelectronics Department, Sumy State University, Sumy, Ukraine • Increase sensitive mass by enrichment • Active background rejection through 𝛼 / (𝛽-𝛾) separation • Goal: ➡△EFWHM ≤ 5 keV @ 2615 keV ➡B = 0.1 c/ton/y in ROI ➡<m𝛽𝛽> ~ 10 meV discovery sensitivity (10 yrs of live time) •CUORE has successfully demonstrated that a ton scale bolometric experiment is feasible. •CUPID will build on the experience of CUORE and use its cryogenic infrastructure. •Li2MoO4 detectors recognized as baseline •Enrichment > 95% •~ 1500 crystals with ~ 250 kg of 100Mo •Demonstrated active background rejection. [see Poster ID 419. on the CUPID-Mo experiment by Benjamin Schmidt] Rendering of CUORE cryostat with 1500 crystals inside it •Dominant background is degraded alphas from surface contamination •Leverage energy loss mechanism in the crystal to tag particle type •Use auxiliary low temperature calorimeter to detect light. Should have High radiopurity Low heat capacity High photon collection efficiency Very low threshold (~ 100 eV) Excellent timing resolution to discriminate the 2𝜈𝛽𝛽 pile up events from 0𝜈𝛽𝛽 events. Particle ID •Low transition temperature with relatively fast fabrication time possible with “bilayers” •Negative electrothermal feedback keeps TES stable and decreases sensor time constant ; faster pulses •Iridium goes superconducting at ~ 140 mK. We use the proximity effect of a normal metal (like, Au and Pt) to reduce the Tc. Device specification: •2” Silicon wafer as optical photon absorber •Ir/Pt (100 nm/60nm) bilayer with Nb traces as electrical leads. •Transition temperature of ~ 37 mK •Sensor dimension 300 𝜇m x 300 𝜇m • We have deposited Au pads, coupling the TES to the wafer for better phonon collection efficiency • Tc relatively unchanged with addition of Au pads but signal-to-noise improves drastically. square Ir/Pt bilayer TES square Ir/Pt bilayer TES in the middle with Au pads on both sides IV characteristics • We can operate the detector down to 10 mK by choosing a suitable bias point. • Due to the steep slope in the biased region, the sensitivity of a TES is much larger than NTD- Ge thermistors (CUORE like sensors) Timing resolution • Generate a train of blue LED light pulse with known separation time >> decay time • Examine distribution of trigger time between the subsequent pulses in detector response • Timing resolution of 𝛥t ~ 5 𝜇s • Detector satisfies the criteria for rejecting 2𝜈𝛽𝛽 pile up events (top) Detector response to train of LED pulses of varying amplitude inj