SIDDHARTA

future precision measurement of kaonic atoms at DANE

Florin Sirghi

LNF SPRING SCHOOL "Bruno Touschek"

In Nuclear, Subnuclear and Astroparticle Physics     

Frascati (Italy), May 17th - 21st, 2004

SiSilicon licon

DDrift rift

DDetector foretector for

HHadronic adronic

AAtom tom

RResearch by esearch by

TTiming iming

AApplicationspplications

The obtained DEAR result:

represents indeed the best measurement performed on Kaonic Hydrogen up to now

BUTwhat we are aiming for is

few eV precision measurement of kaonic kaonic hydrogenhydrogen 1s level shift

first measurement of kaonic deuteriumkaonic deuterium

in order to determine the isospin dependent KN in order to determine the isospin dependent KN scattering lengths at percent level precisionscattering lengths at percent level precision

SIDDHARTA Scientific Programme

Kaonic helium measurement towards the study of deeply bound nuclear kaonic state.

Other light kaonic atoms measurement (Li, Be…).

Investigate the possibility of the measurement of other types of hadronic exotic atoms (sigmonic atoms).

Charged kaon mass precision measurement.

SIDDHARTA Collaboration

LNF- INFN, Frascati, Italy

IMEP- ÖAW, Vienna, Austria

IFIN–HH, Bucharest, Romania

Politecnico, Milano, Italy

Max-Planck-Institute for Extraterrestrial Physics, Garching, Germany

PNSensor GmbH, Munich, Germany

RIKEN, Japan

The choice of the detector

A good X-ray detector, which preserves

all good features of the CCD

large active area quantum efficiency energy resolution linearity and stability

Trigger capability (fast shaping times – 1s) for background rejection

The classical PIN (Positive-Intrinsic-Negative) diode detector

The anode capacitance is proportional to the detector active area

n

n+

p+ -Vcc

ANODE

Entrance window

n

n+

p+ -V cc

p+

The Semiconductor Drift Detector

AnodeThe electrons are collected by the small anode,characterized by a low output capacitance.

Advantages: very high energy resolution at fast shaping times, due to the small anode capacitance, independent of the active area of the detector

Entrance window

ANODE

The Silicon Drift Detector with on-chip JFET

JFET integrated on the detector• capacitive ‘matching’: Cgate = Cdetector

• minimization of the parasitic capacitances• reduction of the microphonic noise• simple solution for the connection detector-electronics in monolithic arrays of several units

The integrated JFET

Detector produced at Max-Planck-Institute for Extraterrestrial Physics, Garching, Germany

Quantum efficiency of a 280 m thick SDD 55Fe spectrum measured with a SDD (5 mm2) at –10°C with 0.5 s shaping time

Silicon Drift Detector performances

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1100

200

300

400

500

600

700

800

A (cm-2)

FW

HM

(eV

)

SDD PIN Si(Li) 150 K 5.9 keV line

PIN Tsh=20us

Si(Li) Tsh=20us

SDD Tsh=1us

Spectroscopic resolution: detector comparison

hIK

IA

h

tIA

tdr max

Timing with the anode signal

Triggered acquisition

Kaontrigger

Concidencewindows

Detectedpulses

Consideredpulses

Kaon trigger X-ray pulseBackground pulse

dr max

Background reductions S/B = 5/1

beam pipeand kaon trigger

vacuum chamber

feed-throughs forSDD electronics

port forSDD cooling

targetcooling line

SDD pre-amplifierelectronics

SDD detector chip

target cell

lead table

SIDDHARTA setup version 1SIDDHARTA setup version 1

Beam pipe

Cryogenic target cellKaon trigger

SIDDHARTA setup version 2SIDDHARTA setup version 2

e+

e-

SDDs array

Kaon stopping distribution inside hydrogen target for a toroidal setup

Kaons stopped inside target ~ 30% (all generated)

Signal: ~ 30 times more than in DEAR

SIDDHARTA Kaonic hydrogen simulated spectrum

Precision on shift ~1 eV

integrated luminosity60 pb-1

S/B = 5/1

SIDDHARTA Kaonic deuterium simulated spectrum

Precision on shift < 10 eV

integrated luminosity100 pb-1

S/B = 1/4

Test of the 30 mm2 SDD

electrode Voltage Current

R#1 - 10 V 20.8A

IGR - 18 V 0.5A

Back - 91 V <0.1A

R#N - 178 V 20.9A

IS,OS gnd -

Drain +12 V 400A

Detector biasing parameters

5000 5500 6000 6500 7000Energy [keV]

0

1000

2000

3000

4000

Cou

nts

139 eV FW H M T = - 40°C, tsh=0.75s

Conclusion

Continuing tests of detectorsContinuing tests of detectors

Finalizing the design of the new experimental setup:Finalizing the design of the new experimental setup:front-end electronicsfront-end electronics, mechanics, cryogenics, vacuummechanics, cryogenics, vacuum

20062006

Assembly of the setup on DAAssembly of the setup on DANENE and data takingdata taking