ASTROGAM Calorimeter: detector and FEE. Martino Marisaldi INAF IASF Bologna 1 st ASTROGAM Workshop, Roma Dec. 2013

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1 ASTROGAM Calorimeter: detector and FEE Martino Marisaldi INAF IASF Bologna 1 st ASTROGAM Workshop, Roma Dec. 2013

2 Compton telescopes 2 interaction positions + time-of-flight COMPTEL Redundant photon interaction position (removes direction ambiguity) NCT, LXeGRIT, Most ACT concepts Electron tracking MEGA, TIGRE, GRIPS ASTROGAM Credits: Andreas Zoglauer PhD Thesis 09/12/14 M. Marisaldi - ASTROGAM WS Rome 2

3 Compton kinematics 1 What we want: What we need: Must measure with the highest precision direction and energy of the recoil electron and scattered g Credits: Andreas Zoglauer PhD Thesis 09/12/14 M. Marisaldi - ASTROGAM WS Rome 3

4 Compton kinematics 2 If I don t know anything of the recoil electron direction: Credits: Andreas Zoglauer PhD Thesis 09/12/14 M. Marisaldi - ASTROGAM WS Rome 4

5 Credits: Andreas Zoglauer PhD Thesis Angular resolution Angular resolution depends on the accuracy of energy measurement for e - and g Recoil electron only 2 MeV g Scattered gamma-ray only 09/12/14 5 Angular resolution requirements pose constraints on energy resolution M. Marisaldi - ASTROGAM WS Rome

6 The ingredients: high-z absorber (CsI(Tl), LaBr3 ) Low-noise photodetector Low-noise front-end electronics Few mm position resolution: tradeoff pixel size vs. power consumption / complexity. 09/12/14 M. Marisaldi - ASTROGAM WS Rome 6

7 Need for low-noise photodetector and low-noise front-end electronics ~300 e - rms a 1/E a 1/E 1/2 ~30 e - rms Fiorini et al. TNS (2006) 09/12/14 M. Marisaldi - ASTROGAM WS Rome 7

8 Silicon Drift Detector Basic Principle M. Marisaldi - ASTROGAM WS Rome 8

9 SDD development and applications in Italy: the INFN XDXL and ReDSoX R&D projects Technology Science 06/11/2013 M. Marisaldi - Paris 9

10 Post-ALICE SDD INFN & FBK ALICE (2002) INFN & Canberra Proof of Concept ALI2 ( ) INFN & FBK Shift to FBK low-e improvement, low-power, humidty,.. XDXL-1 ( ) INFN & FBK Large pitch INFN Trieste Design XDXL-2 (end-2012) INFN & FBK 145 mm & 970 mm pitch R. Campana et al. Imaging performance of a large-area M. Marisaldi Silicon - ASTROGAM Drift Detector WS Rome for X-ray astronomy NIM-A 633 (2011) 22 10

11 Very Low Noise front-end electronics VEGA ASIC (design by Politecnico Mi & Uni PV, production by AMS 0.35mm MPW): Low-noise low-power mixed signal ASIC for SDD readout Optimized for high resolution X-ray spectroscopy < 15 e- RMS For each channel: pre-amplifier: <15 e- RMS shaping amplifier discriminator peak and hold channel tuning (thr, on/off, etc) power consumption: 418 mw/ch M. Ahangarianabhari et al., IWORID 2013, to be submitted to Journal of Instrumentations M. Marisaldi - Paris 11

12 C. Labanti et al., SPIE Proc F. Perotti et al., SPIE Proc Silicon Drift Detectors coupled to CsI(Tl) scintillators SDD array (MEGA chip) by PNSensor gmbh (ASI funded R&D, <2009) SDD single elements and array by INFN / FBK (INFN / INAF funded R&D) X-ray spectrum 55 Fe 8000 counts 6000 FWHM = 260 ev FWHM = 270 ev Energy (kev) g-ray spectrum 137 Cs counts 400 FWHM = 6.2% /11/2013 M. Marisaldi - Paris Energy (kev) 12

13 Architectures for space g-ray calorimeters INTEGRAL IASFBO AGILE IASFBO 09/12/14 M. Marisaldi - ASTROGAM WS Rome 13

14 Hodoscopic architecture 1200 Light attenuation ch (AU) PD cm PD A x = æ ln u ö (0,A) ç è u (0,B) ø - DaL + 1 ln æ U -O ö B B ç 2a _ 2a _ èu A -O A ø AGILE MCAL heritage PD B E = _ e a L 2 e Dax u (0,A) u (0,B) (U A -O A )(U B -O B ) 09/12/14 M. Marisaldi - ASTROGAM WS Rome 14

15 Position resolution AGILE-MCAL: 39 cm Csi(Tl) bar + PIN PD 14 7 ~10 MeV Labanti et al., NIM A (2009) cm Csi(Tl) bar + single SDD MeV Labanti et al., IEEE NSS Conf. Rec. (2008) a. u mm /12/14 M. Marisaldi - ASTROGAM WS Rome 15

16 A modular approach SDD 2x2 array Wrappaed CsI(Tl) bars Credits: F. Fuschino - UniBo 09/12/14 M. Marisaldi - ASTROGAM WS Rome 16

17 A modular approach Wrappaed CsI(Tl) bars Credits: F. Fuschino - UniBo To back-end electronics By flex cables 09/12/14 M. Marisaldi - ASTROGAM WS Rome 17

18 Summary Bottom CAL for ASTROGAM: 2D matrix of CsI(Tl) bars with double-side SDD readout SDD by INFN + FBK + INAF IASF Bo & IAPS Roma Possible contribution to FEE by Poli.Mi and Uni. Pv. IDEFiX by CEA can work as well. Both need minor R&D. Not so many degrees of freedom (to be fixed by simulations / constraints): Size? Si tracker size: cm Thickness? 5 cm: 81 kg CsI, 4 cm: 65 kg Pixel size? Baseline 5mm 2x14400 ch for 60cm side. <0.5mW/ch 15W FEE + buffer power 09/12/14 M. Marisaldi - ASTROGAM WS Rome 18