new developments of sdd-based x-ray detectors for the siddharta-2 experiment

New Developments of SDD-Based X-Ray Detectors for the Siddharta-2 Experiment

R. Quaglia1,2, L. Bombelli3, C. Fiorini1,2, G. Giacomini4, F. Ficorella4, A. Picciotto4 , C. Piemonte4

1Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy2INFN Sez. di Milano, Milan, Italy3XGLab srl, Milan, Italy4Fondazione Bruno Kessler, Trento, Italy

Riccardo QuagliaSeoul, IEEE NSS/MIC/RTSD 2013

2

SIDDHARTA-2SIlicon Drift Detector for Hadronic Atom Research by Timing Applications

• LNF- INFN, Frascati, Italy• SMI- ÖAW, Vienna, Austria• IFIN – HH, Bucharest, Romania• Politecnico, Milano, Italy• Fondazione Bruno Kessler, Trento, Italy• RIKEN, Japan• Univ. Tokyo, Japan• Victoria Univ., Canada


3Upgrade of the X-ray spectrometer for the SIDDHARTA-2 experiment

K-

Nucleus

X-ray

EM valueK-p Kα

Kaonic hydrogen

Kα Kβ

higher

SDD array

M. Bazzi et al., “Preliminary study of kaonic deuterium X-rays by the SIDDHARTA experiment at DAFNE”, Nucl. Phys. A907 (2013) 69-77.

Upgrade the apparatus with 200 cm2 of new SDD detectors

Strong interaction studies al low energy (non-perturbative QCD in strangeness sector) through precise X-ray spectroscopy measurements of Kaonic atoms transitions


4

1 cm2 x 144 SDDs

SIDDHARTA-1 DETECTOR ARRAYS (produced at MPI-HLL, Munich, Germany)


5Development of SDDs by Politecnico & FBK

FBK production:• 4’’ wafer• 6’’ wafer upgrade now operative

• Started in 2011 within a project supported by ESA for LaBr3 scintillator readout with SDD arrays.

• Back entrance window optimized to achieve QE > 80 % at 380 nm ( suitable also for soft X-rays).

• Considered suitable for the upgrade of the Siddharta-2 apparatus, with preliminary evaluation on prototypes in 2012/2013

8 x 8 mm Array: 9 SDDs (8 x 8 mm each)

12 x 12 mm

Average leakage current: 2 nA/cm2


6Front-end readout strategy

SDD

CUBE

radiation entrance window

SDD CUBE

CMOS Preamplifier ‘CUBE’ (recently developed at Politecnico di Milano*)• the whole preamplifier is connected close to the SDD (and not only the FET)• the high transconductance of the input MOS compensates the larger capacitance

introduced in the connection SDD-FET• the remaining part of the electronics (the ASIC of analog processing) can be placed

relatively far from the detector (even 10-100cm)

30 ns55Fe signal (SDD)

*L. Bombelli, et al., “ “CUBE”, A Low-noise CMOS Preamplifier as Alternative to JFET Front-end for High-count Rate

Spectroscopy”, Nuclear Science Symposium Conference Record, 2011, N40-5.


7Spectroscopy with CUBE preamplifier

SDD characteristics:• Area = 10 mm2 (round)• T= -40 °C (Peltier cooling)• uncollimated source

1.0 ms shaping time (optimum)

250 ns shaping time!

126.4 eV FWHM

(ENC= 5.0 e- rms)

55Fe spectrum

123.0 eV FWHM

(ENC= 3.7 e- rms)


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Two biasing techniques of the back electrode:• independent bonding;

• biasing with punch-through mechanism;

punch-through

holes current density

The SDD is operated with the back electrode disconnected and biased by means of the punch-through technique.This eliminates bondings on the backside reduction of dead area in the detector hybrid

Single 8 x 8 mm detector (64 mm2)

Fiorini, C.; Longoni, A.; Lechner, P., "Single-side biasing of silicon drift detectors with homogeneous light-entrance window," Nuclear Science IEEE Transactions on, Aug 2000.

Test in a set-up with vacuum chamber and cryostat with a minimum temperature of 50 K.Low temperature operations are needed is Siddharta-2 to speed-up the drift time which is important for timing of the experiment.


9FW

HM

@ 6

keV

[eV

]

Shaping Time [µs]0 2 4 6 8 10 12 14

120

122

124

126

128

130

132pre esa 160K standard biasing

pre esa 160k punch throught back biasing

No penalizations with temperatures below 200 K. In figure measurements at 160 K.Similar performances below this temperature. Uncollimated source.

Single 8 x 8 mm detector (64 mm2)

123.9 eV FWHM

ENC = 4.0 e-

y scale (FWHM) very small, 6 eV on all range (0.5 μs to 12 μs shaping time)!

standard biasing

punch-through back biasing


10Single 12 x 12 mm detector (144 mm2)

First sampled tested recently.

Successfully tested very good result at 150K, 100K and 50K. Test only with standard biasing of the back electrode. Uncollimated source.

124.7 eV FWHM

4 μs shaping time at 60 K 0.5 μs shaping time at 60 K

130.4 eV FWHM

12 mm 8 mm

8 mm

12 mm


11Monolithic array of 3x3 SDDs (6.7 cm2)

26 mm

Ceramic carrier

connector

9 holes for bondings

CUBEpreamplifier

Bias through the punch–through mechanism (no bonding on the back side).

1mm dead space on each side: 85% active area

26 mm


12

Channel #1

PeakStretcher

Shaping Amplifier(7th order)

BaselineHolder

Peak Stretcher

Logic

Digital Section

Channel #2OutputBuffer

MUX

Channel #27

Reg

iste

rs SPIinterface

OUT

Mux Logic

Voltage and Current References2nd ASIC

TRIGGER LOGIC

c

TR_OUTTR_PRE

cTR_IN

IN_1

IN_2

IN_27

27 channels Shaper filter Semi-Gaussian 7th order complex poles. Peaking Time 2, 3, 4 or 6µs 3 Gain: 10k, 20k, 30k equivalent e- SPI 160 bits; Multiplexer 27 to 1 MUX clock 10 MHz Digital transfer standard LVDS

Test of 9 SDDs arrayASICs designed for gamma-spectroscopy with SDD

Quaglia, R.; et al."Readout electronics and DAQ system for silicon drift detector arrays in gamma ray spectroscopy applications," IEEE NSS/MIC/RTSD, 2012.

Peloso, R. et al. "Development of a detector based on Silicon Drift Detectors for gamma-ray spectroscopy for astronomy applications," IEEE NSS/MIC/RTSD, 2012.

Spectra with 1” LaBr3 scintillator (57Co, 137Cs, 60Co) and arrays with 9 SDDs


13SDDs array readout with the ASIC

Preliminary tests with SDDs array made with Peltier cooling at temperature -30 °C

Future tests with array in vacuum chamber and lower temperature

Results comparable with single channel measured at similar temperature

Nine spectra acquired with the ASIC, average FWHM: 145.21

note: leakage current still not negligible at this temperature: the resolution is consistent at this temperature for a 64 mm2

large device.

139.5 145.1 146.1

141.6 146.1 145.8

141.5 146.3 154.9

FWHMFWHM FWHM

FWHM FWHM FWHM

FWHM FWHM FWHM


14Conclusions and future works

• Experimentation of single SDD (8x8mm2 and 12x12mm2) as well as first arrays (3x3 units) show very good energy resolution performances

• SDD technology together with CUBE preamplifier looks suitable for the Siddharta-2 upgrade

• Design of a new readout ASIC compatible with SIDDHARTA-1 DAQ.

• Definition of the basic detector for SIDDHARTA-2, size of the single element, number of SDDs per module, ecc…


15

Thank you for listening!

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new developments of sdd-based x-ray detectors for the siddharta-2 experiment

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