Semiconductor detectors II

22nd March 2012

Semiconductor material properties

Physical properties of materials

sets the boundaries to its usability in

given measurement device application.

Up: Basic properties of several

semiconductor materials.

Left: Charge carrier transport

properties of selected semiconductors.

J.P.

Ponp

on: N

IM A

551

(200

5) 1

5-26

What kind of detector is required for given application?

-Energy range and energy resolution;

Si is efficient at low energies up to 10 keV, whereas CdTe is efficient up to 80 keV

-Array size and pixel density;

Depends on optical geometry: PSF of photons on focal plane should correspond pixel size

-Detector read-out time;

more pixels slower read-out

slower readout signal pile-up

arXiv:1202.6271v1

Different techniques used that are used to construct imaging X-ray detectors: 3. Hybrid pixel detector, 4. MOS CCD, 5, p-n CCD and 6. DEPFET CCD (J.P. Ponpon: Semiconductor detectors for 2D X-ray imaging)

Semiconductor Drift Detectors

• PN junctions in both sides

• Generates vertical and

lateral drift field

• Low noise

• Charge carriers induce

signal only on arrival

to JFET

Suitable for high count

rate measurements

Tobias Eggert: Semiconductor x-ray D

etectors

Drift detector field configuration

Tobias Eggert: Semiconductor x-ray D

etectors

Examples of X-ray Semiconductor devices in space astronomy

NASA’ s Mars rovers’ APXS instrument

• APXS include Si(Li) semiconductor X-ray drift detector (SDD) and several alpha detectors

• Updated version of Mars 96 and Pathfinder instruments• Detectors measure X-ray fluorescence and Particle induced X-ray emission:

Onboard there are six 244Cm sources (A 30 mCi) irradiating Martian soil with incident 5.8 MeV -particles and 14.1 and 18 keV X-rays

• APXS is used to determinate the elementary composition of Martian rocks set constraints to mineral composition

• SDD energy range from 1-16 keV• SDD generates 512 –channel X-ray spectrum with EFWHM ~ 160 eV @ 6.4

keV• Detectors operate in measurement temperature of -30 °C provided by

peltier cooling• Updated version on a way to Mars onboard the MSL lander

APXS’s SSD detector construction (up) and schematics of signal handling chain

SSD ShaperDiscri-minator ADC

MCA

Courtesy of Nasa

Spectrum of martian soil as measured by spirit’s APXS X-ray detector

BepiColombo

• BepiColombo is ESA’s and JAXA’s joint mission to planet Mercury due to be launched in 2015

• Onboard MIXS/SIXS -instruments (Mercury Imaging X-ray Spectrometer and Solar Intensity X-ray Spectrometer):-MIXS consist of two (DEPFET) X-ray detector arrays which measure X-ray fluorescence radiation from planet surface, induced by solar radiation -SIXS consist of three HPSi PIN detectors (and a particle detector) which measures the solar X-ray radiation spectra, which is used as a reference for MIXS instrument

• Combining the information of MIXS and SIXS detectors, the elementary composition of hermean surface can be determined

• Spectroscopic performance: -MIXS-T: 0.5-7.5 keV, with EFWHM ~ 100 eV @ 1 keV-SIXS: 1.5 – 20 keV with EFWHM ~ 250 eV @ 6 keV

• Detectors operate in measurement temperature of -45... -20 °C provided by peltier cooling

BepiColombo MIXS has two identical DEFPET macropixel matrix devices on

placed on the two focal planes:

MIXS-C has 10° FOV, which enables fluorescence measurements of distance

scales of 70-270 km, sufficient for examination of major terrains

MIXS-T has 1° FOV with angular resolution of 1.7 arcmin and effective area of

120 cm2 @ 1 keV and 15 cm2 @ 10 keV. This provides more

accurate measurements (< 10 km resolving), but needs higher X-ray fluxes

from the Sun

Image:J.Treis

et Al., doi10.1088/1748-0221/4/03/P03012

BepiColombo SIXS instrument consists of three identical HPSi PIN detectors

and a particle detector (CsI(Ti) scintallator). Thermal conditions for detectors

are maintained with peltier cooling

and heat radiator.

Each Si detector has its own radioactive

Fe-55 source for spectral calibration.

Images: J. H

uovelinet al. / Planetary and Space Science 58 (2010) 96–107

BepiColombo spacecraft from bottom to the top: BepiColombo transfer module;Mercury Planetary Orbiter (MPO);Sun shield for MPO;Mercury Magnetospheric Orbiter(MMO);

The transfer module has solar-electric propulsion unit which is used to get to the orbit around the planet MercuryThe chemical propulsion unit is usedto escape Earths gravity pull up to thedistance of the Moon.

Images:´ESA

XMM-Newton

European X-ray Multi Mirror (XMM) tele-

scope’s main instrument on focal plane is

the European Photon Imaging Camera

(EPIC). It consists of two 2.5 Mpx

metal-oxide semiconductor (MOS) CCDs,

and one p-n CCD camera.

- General performance characteristics MOS CCD’s: FOV 30 arcmin, energy range 0.15 - 15 keV, E/ E = 20 – 50, angular resolution 6 arsec

-Working temperature of -100 °C provided by liquid nitrogen cooling-Measure in photon counting mode with fixed readout-frequency (dependent on read-out mode)Left: Each of the MOS CCD’s structures of 7 array chips with 600x600 40 m2 pixels

Images: Courtesy of ESA

Left: EPIC p-n camera with

readout cables to preamplifier.

-EPIC pn-CCD camera consist of 12 identical 64x198 pixel arrays placed on the single wafer-Pixel size of 150x150 m2 yield 3.3 arcsecangular resolving capability-Imaging area of covers 97 % of telescopes FOV-Pixels are read row by row. Camera can be used in full array read-out mode, or by using read-out modes that read fewer pixels. This increases reading frequency and helps to avoid pile up effects in relatively high flux

Images: Courtesy of ESA

Schematics of the XMM-Newton telescope and focal plane.The three cameras each have their own Wolter I grazing incident mirrors (up left). In the optical path of two of the cameras, ReflectingGrating Assemblys are mounted for high resolution spectroscopy (up right).

Images: Courtesy of ESA

and XMM

-New

tonSO

C, VILSPA

X-ray light curve of OY Carinae constructed by combining data from all three EPIC cameras to 2000 time bins /orbital period . The light curve is due to the eclipsing binary system with white and red dwarfs.

arXiv:astro-ph/0307436v1

s

Up: Images of different wavelength taken of Andromeda galaxy. XMM-EPIC on bottom right.

Right: XMM-EPIC image in more detail. Differentcolours corresponds for different energies:Red is for 0.3-0.7 keV, green 0.70-1.2 keV andblue 1.2-7.0 keV photons. This EPIC image has been constructed of several exposures totalling over 20 days ofexposure time.

Courtesy of ESA

Literature

• J.P. Ponpon: Semiconductor detectors for 2D X-ray imaging, NIM A 551 (2005) 15-26

• J.Treis, R Andritschke et Al., Pixel Detectors for imaging spectroscopy in space, doi: 10.1088/1748-0221/4/03/P03012