A. Monfardini, IAP 26/06/ Kinetic Inductance Detectors for CoRE-like applications Potentially involving (from the technical point-of-view): - Grenoble (Néel, LPSC, IRAM, IPAG, CEA-LETI) - Cardiff (others in UK ?) - The Netherlands (SRON, Delft) - Paris (APC, CSNSM, IAS, SaP) - Roma - Spain.. others ?.. others ?

A. Monfardini, IAP 26/06/ KIDs working principle f IN-OUT transmission (amplitude) Dark, T << T c increase in L k Light: increase in L k Change in phase (  ) increase in R Light: increase in R Change in amplitude (  A) fifi IN-OUT transmission (phase) From the theory :  f   L K   P  f = frequency shift  P = incoming power The incoming photons break Cooper pairs (supercurrent carriers) in a superconducting LC resonator  measurable signals  AA ff

A. Monfardini, IAP 26/06/ Intrinsic linearity demonstrated ( h· << k·T ) Measured using the NIKA Sky Simulator f 0  2 GHz

A. Monfardini, IAP 26/06/ KIDs: multiplexing principle IN from DAC and UPCONVERTER OUT to DOWNCONVERTER and ADC f0f0f0f0 f1f1f1f1 …… f N-2 f N-1 Inductance L K + L G Capacitor C Feedline 50  One of the C lines is modulated by lithography to adjust every resonance (e.g. f res  1.5  0.2 GHz) natural f-domain multiplexing  natural f-domain multiplexing since f/  f  10 5 high MUX factor is possible  since f/  f  10 5 high MUX factor is possible High-Q superconducting (R  0) LC resonator : Lumped Element KID design :

A. Monfardini, IAP 26/06/ State-of-the-art

6 Snapshot taken today ACHIEVED (mm and sub-mm applications): - Background limited (best pixels) for ground-based applications ( GHz) - Electrical NEPs in the low W/Hz Optical NEPs under small loading (0.1pW) in the low W/Hz 0.5 (in Al and TiN) - Full system (hundreds pixels) up and running on a big telescope (NIKA) - Fundamental solutions found for photometric calibration (modulated read-out) - larger interest in the Community  getting exponential ONGOING: - kilo-pixels arrays uniformity to be investigated (e.g. NIKA, MUSIC, AMKID...) - space-adapted configurations (main problem: cosmic-rays interaction)  HUGE evolution from the last « BPol » meeting

A. Monfardini, IAP 26/06/ NIKA run 3 – October 2011 mostly nights » One week « mostly nights » run at the 30-m IRAM telescope 150 GHz & 240 GHz – pixels LEKIDs NEFD  20 mJy  s 0.5 Design: Grenoble Fabrication: Grenoble Electronics: Grenoble-US NEFD  100 mJy  s 0.5 Design: Grenoble Fabrication: Grenoble Electronics: Grenoble-US NIKA 2011 : - cryogen-free cryostat - magnetic screening - improved photometry (< 10%) - dual polarisation Sensitivity at 2 mm is now comparable to state-of-the-art TES (e.g. NASA Goddard). NEP  W/Hz 0.5 DR21(OH) star-forming region

A. Monfardini, IAP 26/06/ NIKA run 4 First permanent KID camera - 06/2012 Available for Science until waiting for the big (6.5’) Camera Sensitivity improved at 1.25mm, more pixels ( ) A couple of dedicated observational runs (open to IRAM Community) per year.

A. Monfardini, IAP 26/06/ Kilo-pixels arrays: NIKA v0 - 1,020 pixels (150 GHz) -  2,000 pixels (240 GHz) 80 mm 3/4 feedlines OK (750 pixels). Resonances OK, Optical response OK. For detailed testing (e.g. noise, cross-talk) need 4 final NIKA electronics boards (NIKEL v1)

A. Monfardini, IAP 26/06/ TiN LEKID optical sensitivity Films: Films: TiN JPL (H.G. Leduc) Way too sensitive. Way too sensitive. Must mount a diaphragm at the cold (0.1K) pupil to reduce the optical loading by a factor with respect to the NIKA standards (  10 pW per pixel). Power per pixel: << 1pW (band GHz). Example (7/2/2012 optical measurements):  P = 0.04pW per pixel (80K vs. 0K on focal plane) is detected, on 64 typical pixels, with a S/N per unit band of 2000  8000 Hz 0.5 (median 4000) Means, for this loadings, opticalNEP of 5· to 2· W/Hz 0.5 an optical NEP of 5· to 2· W/Hz 0.5, constant in the range 0.1  10 Hz ! Caution 1: to be confirmed by further measurements ! Caution 2: changing the T working point we have noticed large variations in the optical response. Must measure again at slightly higher T. Measurements reported here performed at 85 mK (working point not optimized, but since we don’t understand everything.... better being prudent). Design « NITA 1.2»: classical LEKID meander – not particularly optimised.

A. Monfardini, IAP 26/06/ Noise decorrelated Credit: Juan Macias-Perez (LPSC Grenoble) < W/Hz 0.5 Raw frequency noise Decorrelated noise At 80mK (  T c DC /11) still very sensitive to base T (e.g. 1kHz / mK !)

A. Monfardini, IAP 26/06/ SRON 1 Credit: A. Barishev, J. Baselmans, A. Endo, L. Ferrari, S. Yates

A. Monfardini, IAP 26/06/ SRON 2 Credit: A. Barishev, J. Baselmans, A. Endo, L. Ferrari, S. Yates

A. Monfardini, IAP 26/06/ Electronics (example)

A. Monfardini, IAP 26/06/ Power consumption : negligeable at < 4 K  10  W/ch. at 4 K  100 mW/ch. at 300 K NIKEL v1: the future NIKA read-out NIKEL board v1 (2012). NIKEL board v1 (2012). 500 MHz, 400 channels (ADC 12 bits, DAC 16 bits) For details see: For details see: O. Bourrion et al., Journ. of Instrum. 6, Issue 06, 6012 (2011) O. Bourrion et al., in press, arXiv: (2012) No constrains of power for NIKA. Not optimised at all.

A. Monfardini, IAP 26/06/ A quite fundamental problem: the electrical cross-talk

A. Monfardini, IAP 26/06/ Resonators electrical cross-talk FULL ARRAY (36 PIXELS) SIMULATION Mainly applies to Lumped Element KIDs

A. Monfardini, IAP 26/06/ Cross-talk hints Best candidate : inductive and/or capacitive coupling between resonators Testing : - Feedline impedance - New meanders - GND plane influence - Trenches..

A. Monfardini, IAP 26/06/ KIDs environmental needs

A. Monfardini, IAP 26/06/ Materials and Environment Substrates: - Sapphire. At the very beginning it seemed a must to suppress phae noise. Now demonstrated it’s not necessary. - Silicon. OK if not oxidated and clean dielectric/metal interface. Superconducting films: - Aluminium (thin, <40nm). Low-frequency cut-off around 100GHz. - TiN. Still tricky and not fully understood. But potential lower f and NEP to be studied... lots of options Magnetic environment: sensitive (resonances shifting). Much less than SQUIDs, but more than MIS. Need classical screening (e.g. high-  + superconductor). Temperature environment: much less sensitive than a bolometer. Optimal base T (e.g. for 150GHz, Al films): 150 mK or lower Optimal base T (e.g. for 90GHz, TiN films): 100 mK or lower. Vibrations environment: much less sensitive than a bolometer. Cosmic hits: fundamentally less sensitive than bolometers (see later). How better it is in practice still to be demonstrated (e.g. making resonators on the same suspended structures used for PACS.. CEA-LETI getting involved).

A. Monfardini, IAP 26/06/ Cosmics Hits

A. Monfardini, IAP 26/06/ Cosmics HFI Credit: Andrea Catalano – LPSC Grenoble

A. Monfardini, IAP 26/06/ LEKIDs under cosmic and x-ray irradiation L. Swenson et al., Applied Physics Letters, 96, Issue 26, id (2010) First ever « cosmic hit movie » (NIKA test array) Single 6 keV x-ray photon observed on 11 pixels Dedicated 16 pixels LEKIDs array A. Cruciani et al., LTD-14

A. Monfardini, IAP 26/06/ Over-gap phonons propagation D.C.Moore et al., APL 100, Issue 23, id (2012) Propagation speed: 6-9 mm/  s < 1  s  in < 1  s the « wave » reaches closest pixels  10  s  in  10  s a big (e.g. 10cm) array is filled t > 10  s  for t > 10  s, phonons decay to thermal and a part leaks to the housing. At the same time, a part (1-10%) of the energy (1-10%) of the energy goes into quasi-particles and produces a signal. After t  s equilibrium between phonons decay/leak (green)  ph phonons decay/leak (green)  ph and quasi-particles lifetime (blue)  qp. Depending on technology details one effet might dominate and determine the pulse lenght. Time (  s)  ph >>  qp

A. Monfardini, IAP 26/06/ Summary: KIDs and Cosmics BASE ASSUMPTION IN ANY CASE SUSPENDED STRUCTURES ARE NEEDED A SMALL LIST OF POINTS (in favour) TO REMEMBER: 1)suspended structure is for cosmics ONLY. Not needed for sensitivity. 2)KIDs are relatively fast. Response typically around 0.1ms; maximum not exceeding 1ms for very low background applications and pure metals. 3)KIDs are not sensitive (very little in fact) to thermal phonons. Only high-energy (T > T c ) phonons can produce a signal. 4) poor efficiency of energy transfer from phonons to quasi-particles. For a solid wafer only 1-10% of the deposited energy goes into measurable signal.

A. Monfardini, IAP 26/06/ THANKS