The SIDDHARTA and SIDDHARTA-2 experiments at DAFNE (sigla KAONNIS) C.Fiorini CDS- INFN Milano 10-06-13

SIDDHARTA SIlicon Drift Detector for Hadronic Atom Research by Timing Applications LNF- INFN, Frascati, Italy SMI- ÖAW, Vienna, Austria IFIN – HH, Bucharest, Romania Politecnico, Milano, Italy MPE, Garching, Germany PNSensors, Munich, Germany RIKEN, Japan Univ. Tokyo, Japan Victoria Univ., Canada

The scientific aim KN scattering lengths through a the determination of the isospin dependent KN scattering lengths through a ~ precision measurement of the shift and of the width of the Ka line of kaonic hydrogen and the first measurement of kaonic deuterium Measurements of kaonic Helium 3 and 4 as well (2p level)

stopped in a target medium Kaonic atom formation e- n ~ sqrt(M*/me) n’ ~ 25 (for K-p) (M* : K-p reduced mass) highly-excited state Auger Electron K- 1) Initial capture deexcite X-ray K- 2) Cascade K- Nucleus 3) Strong interaction Shift and Width of last orbit e.g. 1s for K-p, K-d 2p for K-He 4) Absorption The strong int. width > Radiative trans. width stopped in a target medium

Kaonic cascade and the strong interaction s p d f Ka ~ 6.3 keV = DE2p1s E1s } E2p n 4 3 2 1 Kb

Antikaon-nucleon scattering lengths Once the shift and width of the 1s level for kaonic hydrogen and deuterium are measured -) scattering lengths (isospin breaking corrections): e + i G/2 => aK-p eV fm-1 e + i G/2 => aK-d eV fm-1 one can obtain the isospin dependent antikaon-nucleon scattering lengths aK-p = (a0 + a1)/2 aK-n = a1

SIDDHARTA Scientific program Measuring the KN scattering lengths with the precision of a few percent will drastically change the present status of low-energy KN phenomenology and also provide a clear assessment of the SU(3) chiral effective Lagrangian approach to low energy hadron interactions having implications going from particle and nuclear physics to astrophysics Φ → K- K+ (49.1%) Monochromatic low-energy K- (~127MeV/c) Less hadronic background due to the beam ( compare to hadron beam line : e.g. KEK /JPARC) Suitable for low-energy kaon physics: kaonic atoms Kaon-nucleons/nuclei interaction studies

Detect by two scintillators SIDDHARTA overview Target Detect by SDDs K- e- 510 MeV/c Detect by two scintillators Φ K+ e+ 510 MeV/c 127 MeV/c Δp/p=0.1% x y z 8

Silicon Drift Detector - SDD 1Chip : 1 cm2

SDD-subunit

1 cm2 x 144 SDDs

SIDDHARTA results: - Kaonic Hydrogen: 400pb-1, most precise measurement ever,Phys. Lett. B 704 (2011) 113, Nucl. Phys. A881 (2012) 88; Ph D - Kaonic deuterium: 100 pb-1, as an exploratory first measurement ever, Nucl. Phys. A907 (2013) 69; Ph D - Kaonic helium 4 – first measurement ever in gaseous target; published in Phys. Lett. B 681 (2009) 310; NIM A628 (2011) 264 and Phys. Lett. B 697 (2011);; PhD - Kaonic helium 3 – 10 pb-1, first measurement in the world, published in Phys. Lett. B 697 (2011) 199; Ph D - Widths and yields of KHe3 and KHe4 - Phys. Lett. B714 (2012) 40; ongoing: KH yields; kaonic kapton yields -> draft for publications SIDDHARTA – important TRAINING for young researchers

Background estimation Hydrogen spectrum EM value K-p Kα Kaonic hydrogen Kα Kβ higher KC54 KC65 Ti Kα simultaneous fit Ti Kβ KO65 KO76 KN65 KC75 Cu KAl87 Deuterium spectrum Background estimation

Residuals of K-p x-ray spectrum after subtraction of fitted background Kaonic hydrogen higher Kα Kβ EM value K-p Kα

e1S= −283 ± 36(stat) ± 6(syst) eV Kaonic Hydrogen results: - most reliable and precise measurement ever - need to go for Kd! -> SIDDHARTA-2 e1S= −283 ± 36(stat) ± 6(syst) eV G1S= 541 ± 89(stat) ± 22(syst) eV

SIDDHARTA(-2) in LEANNIS Exotic (kaonic) atoms – probes for strong interaction hadronic shift ε1s and width Γ1s directly observable experimental study of low energy QCD. Testing chiral symmetry breaking in systems with strangeness Kaonic hydrogen scattering lengths, no extrapolation to zero energy precise experimental data important/missing kaonic deuterium (never measured before) determination of the isospin dependent KN scattering lengths Information on (1405) sub-threshold resonance responsible for negative real part of scattering amplitude at threshold important for the search for the controversial „deeply bound kaonic states” (KEK, GSI, DANE, J-PARC) LEANNIS Kick-off meeting, Prague, May 21, 2012 17

improved trigger scheme shielding and anti-coincidence (veto) The SIDDHARTA-2 setup new target design new SDD arrangement vacuum chamber more cooling power improved trigger scheme shielding and anti-coincidence (veto) New SDDs – Milano – 200 cm2 18

SIDDHARTA-2 scientific program 1) Kaonic deuterium measurement - 1st measurement: and R&D for other measurements 2) Kaonic hydrogen at eV precision 3) Kaonic helium transitions to the 1s level – 2nd measurement, R&D 4) Other light kaonic atoms (KO, KC,…) 5) Heavier kaonic atoms measurement (Si, Pb…) 6) Kaon radiative capture – L(1405) study 7) Investigate the possibility of the measurement of other types of hadronic exotic atoms (sigmonic hydrogen ?) 8) Kaon mass precision measurement at the level of <10 keV

Kd measurement program: SIDDHARTA-2 setup including new SDDs foreseen to be ready within Spring 2015 (compatible with financing) ready to enter on DAFNE (after KLOE run*) With an integrated luminosity of 600 pb-1, SIDDHARTA-2 will be able to perform a first X-ray measurement of the strong interaction parameters - the energy displacement and the width of the kaonic deuterium ground state, a fundamental measurement in low-energy strangeness QCD. * LNF Director statement letter This window of opportunity should be realized. 20 20

New development of SDDs by Politecnico & FBK Started in 2011 within a project supported by ESA Considered very suitable for the upgrade of the Siddharta-2 apparatus, with preliminary evaluation on prototypes in 2012/2013 Key features of the proposed technological approach: process of SDD detectors WITHOUT JFET integrated on the SDD itself (as used on current SIDDHARTA apparatus). advantages: - simplicity - much lower production costs (much less techn. steps) - faster production times (3-4 months vs. one year) - much lower dependence of settings/performances on bias voltages than with the present detectors - less sensitivity to latch-up during beam injection SDD readout based on a new charge preamplifier “Cube” (recently developed at Politecnico di Milano): - allows high performances in X-ray spectroscopy still using ‘conventional’ SDD technology (W/O integrated JFET)

Present layouts of SDDs developed in the Polimi-FBK collaboration Array: 9 SDDs (8 x 8 mm2 each) 8 x 8 mm2 single SDD 26mm 12 x 12 mm single SDD FBK production: 4’’ wafer 6’’ wafer upgrade just finished

CUBE Front-end readout strategy JFET integrated on the SDD Now in lowest total anode capacitance limited JFET performances (gm, 1/f) sophisticated SDD+JFET technology Now in Siddharta SDD CUBE radiation entrance window cooler external CUBE preamplifier (MOSFET input transistor) Proposed for Siddharta-2 larger total anode capacitance better FET performances standard SDD technology

CUBE: A full CMOS preamplifier can replace the single JFET+Cf+reset <1mm3 Leakage and photons SDD CUBE reset 55Fe signal (SDD) 30 ns

55Fe spectrum Performances of new SDD technology and CUBE preamplifier 124.6eV FWHM Performances of new SDD technology and CUBE preamplifier SDD characteristics: Area = 10mm2 T= -40°C (ENC= 4.4 e- rms) 1.5 ms shaping time (optimum) 55Fe spectrum 127.4eV FWHM 250ns shaping time best resolution ever obtained with a SDD (even with integrated JFET) at this short shaping time (ENC= 5.3 e- rms)

Stability of the X-ray spectroscopy spectrum with SDD bias

Set-up for testing SDDs: Vacuum Chamber Cryostat cooling down to 50 K Vacuum Chamber Connector to output Special 55Fe source for vacuum application mounted here Connector for bias and output SDD: 8x8 mm2

Stability tests (in Milano, other tests on-going in Frascati) 72 hours FWHM= 126.8eV square SDD: 64 mm2 meas. time: 72 hours T= 100 K Rate: 1.1 kcps Vacuum chamber set-up.

Monolithic array of 3x3 SDDs: an ideal detector for Siddharta-2 upgrade 26mm 55Fe spectra T=-20°C 1mm dead space on each side: 85% active area connector 9 holes for bondings CUBE preamplifier Detector module Ceramic carrier

Upgrade of Siddharta-2 spectrometer based on: new SDDs development CUBE and ASICs readout low dead-area detection module design Few numbers: 200cm2 of SDDs arrays 36 SDDs monolithic arrays 324 readout channels

ASIC to readout the SDD arrays 27 channels Shaper filter Semi-Gaussian 7th order complex poles. Peaking Time 2, 3, 4 or 6µs 3 Gain: 10k, 20k, 30k e-; SPI 160 bits; Multiplexer 27 to 1 MUX clock 10 MHz Digital transfer standard LVDS From/To preamplifiers (Input signals, Reset) ASIC DAQ

Finanziamento e personale Costi previsti per l’upgrade del sistema di rivelazione SDD ed elettronica: produzione SDD 90k Cube preamplifiers 10k readout ASICs 25k ceramic carriers 8k assembly, bonding 20k set-up/boards/comp. 14k DAQ 30k total 197k (~ 1/5 del costo delle stesse voci in Siddharta) In Siddharta il personale di Milano è stato finora supportato dal Politecnico: C. Fiorini, A. Longoni, T. Frizzi, L.Bombelli, + dottorandi, .. Le attività di Milano per l’upgrade di Siddharta-2 sono possibili solo si rende disponibile una copertura di una persona tramite assegno o borsa di dottorato.

Spare slides

Kd measurements with same precision (relative) as kaonic hydrogen one 34