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

2. 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

3. 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)

4. 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

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

6. 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

7. 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

8. 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

10. Silicon Drift Detector - SDD
1Chip : 1 cm2

11. SDD-subunit

12. 1 cm2 x 144 SDDs

13. 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

14. 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

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

16. 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

17. 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

18. 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

19. 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

20. 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

21. 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)

22. 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

23. 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

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

25. 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)

26. Stability of the X-ray spectroscopy spectrum with SDD bias

27. 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

28. 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.

29. 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

30. 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

31. 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

32. 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.

33. Spare slides

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