1. Silicon Drift Detectors
for
Synchrotron Energy Dispersive X-Ray Fluorescence Spectroscopy
(SDD for EDXRF)
Presentation
by
Dr. Saleh Qutaishat
Petra University
Amman – Jordan
Presented
at
the ninth SESAME users’ meeting, 12-14 November, Days Inn Hotel,
Amman, Jordan
2. Introduction
Detector description and its principle of operation
Detector module.
Detector Features and its Performance
EDXRF of Fe 55 Spectrum
Summary and Concluding Remarks.
References
Video Clip on SDD applications
3. Fig. 1.
1) X-ray absorption
Energy of an incident X-ray photon is absorbed by a core-level electron then the
electron is ejected from the atom as a Photo-electron.
2) X-ray Fluorescence
Higher energy core electron fills an empty electron level , and x-ray of fixed energy
is emitted.
4. 2) X-ray Fluorescence
Higher energy core electron fills an empty electron level , and an x-ray of fixed
energy is emitted
6. Fig. 3. Schematic diagram of the SDD.
In the detector’s core; incident X-ray interacts with n-Silicon and produces electron-hole
pairs. The number of electrons produced are proportional to the energy of the interacting
X-ray photon. The electrons move fast towards the anode under the influence of an electric
field parallel to the surface of the detector. The anode is connected to the gate of an
integrated Field Effect Transistor (FET). Once the electrons reach the anode they produce
an electric current signal
The SDD was invented by E. Gatti and P. Rehak in 1983.
8. Fig. 5. Detector Module; a thermoelectrically cooled Silicon Drift Detector (SDD). Also
mounted on the 2-stage cooler are the input FET and a novel feedback circuit. These
components are kept at approximately -55 °C, and are monitored by an internal
temperature sensor. The hermetic TO-8 package of the detector has a light tight,
vacuum tight thin Beryllium window to enable soft x-ray detection.
9. Fig. 6. Block diagram of the SDD module with Peltier cooler and
related electronics of (EDXRF) spectroscopy.
11. Detector Features and its performance
HIGH COUNT RATE - 500,000 CPS
125 eV FWHM Resolution @ 5.9 keV
High Peak-to-Background Ratio - 8200:1
Up to 80mm2 active area X 500 µm thikness
Multilayer Collimator
No Liquid Nitrogen
15. http://www.youtube.com/watch?v=l34JUidTbCk&feature=related
Fig. 11. Video clips for the X-MAX Drift Detector
(SDD) from Oxford Instruments mounted on a
Scanning Tunneling Microscope (STM) and used for
elements identification and mapping.
1Video clipSilicon Drift Detector application
2Silicon drift Detector application Video clip
http://www.youtube.com/watch?v=mZsJI9nnK6I
16. Summary:
A Silicon Drift Detector (SDD) was presented. The detector
structure and its working principle were explained. The detector
is cooled by a Peltier cooling element giving it a great advantage
over liquid Nitrogen cooled detectors.
The detection system has a high energy resolution due to the low
output capacitance of the SDD and the integration of the FET on
the detector. Energy resolution of the system is 125 eV FWHM
at 5.9 KeV Fe Kα.
Due to its short time shaping signal SDD has a high count rate of
500,000 counts per second.
SDDs are famous in being used in Synchrotron energy dispersive
X-ray fluorescence (EDXRF) spectroscopy and in portable XRF
analysis devices.
17. Concluding Remarks:
The key advantage of the SDD is that it has much lower
capacitance than a conventional SiLi detectors of the
same area, therefore reducing electronic noise at short
shaping times.
For X-ray spectroscopy, an SDD has better energy
resolution while operating at much higher count rates
than a conventional semiconductor.
The SDD uses a special electrode structure to guide the
electrons to a very small, low capacitance anode.
18. References:
[1] E. Gatti, P. Rehak, Semiconductor drift chamber - an application of a novel charge transport
scheme, Nucl. Instr. and Meth. 225 (1984) 608-614
[2] J. Kemmer, G. Lutz, New detector concepts, Nucl. Instr. and Meth. A 253 (1987) 365-377
[3] P. Lechner et al., Silicon drift detectors for high resolution room temperature X-ray spectroscopy,
Nucl. Instr. and Meth. A 377 (1996) 346-351
[4] Synchrotron Hard X-ray Microbeam Techniques, Antonio Lanzirott, the University of Chicago,
Center for Advanced Radiation Source.
[5] http://www.oxinst.com/Campaigns/microanalysis/eds/detectors/large-area-silicon-drift-
detector/Pages/x-max-sdd.aspx
[6] Silicon Drift Detector with On-Chip Electronics, for X-Ray Spectroscopy
KETEK GmbH, Am Isarbach 30, D-85764 Oberschleißheim, GERMANY.
[7] Energy resolving detectors for X-ray spectroscopy, by J Morse, Detector Unit -ISDD , European
Synchrotron Radiation Facility, ESRF,
19-02-2010.
19. [10] Semiconductor Detectors, physics and practical application issues:
H Spieler, ‘Semiconductor Detector Systems’, OUP, 2005
G Lutz, ‘Semiconductor Radiation Detectors: Device Physics’, Springer Berlin 1999
[11] G Knoll ‘Radiation Detection and Measurement’, Wiley , 2000
[12] Design of microelectronic thermal detectors for high resolution radiation spectroscopy,
S. Qutaishat, P. Davidsson, P. Delsing, B. Jonson, R. Kroc, M. Lindroos, S. Norrman and G. Nyman,
Nucl. Instr. and Meth. A342 (1994) 504.
[13] Silicon thermal detectors for single quanta of radiation: fabrication, statistical fluctuations of
phonons, physical properties and operation, P. Davidsson, P. Delsing, B. Jonson, R. Kroc, M. Lindroos,
S. Norrman, G. Nyman, A. Oberstedt and S. Qutaishat,
Nucl. Instr. and Meth. A350 (1994) 250.
[14] Design and implementation of a computer interface for data acquisition in nuclear physics
Laboratories, By Saleh Qutaishat, 1986.
[15] Design and development of crystalline thermal detectors for single quanta of radiation and high
resolution radiation spectroscopy, by Saleh Qutaishat, Published 1994,
ISBN: 9171970126 / 91-7197-012-6.
[8] http://www.pndetector.de/broxDL .
[9] Swiss Light Source SLS and Paul Scherrer Institute Equipment,
http://www.psi.ch/sls/optics/equipment
