Our Product:

A very fast X-ray detector for high-resolution spectroscopy near room temperature. In combination with a scintillator the chip can be used as Gamma-detector.

A wafer of drift detector fabrication showing various chip types.	A mounted droplet shaped SD3 of 5 mm2 detector area with homogenous entrance window.

Key Parameter:

Active Area	5mm2 - 30mm2
Sensitivity	> 90% f. 200eV -15KeV
Maximum Counting Rate	up to 106 cps
Energy Resolution	typ. 128 - 145eV FWHM @MnK,-200C,
Peak-to-Background	2000-10000@MnK, ,-200C

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Short Detector Description:

For optimum performance and high quantum efficiency the detector is operated in the full depletion mode with a sensitive thickness of 450 µm. Active detector areas vary between 5 mm² and 30 mm^2.

Thanks to the small anode and the integrated first transistor energy resolution and count rate capability are high. Counting rates up to 1 MHz can be recorded. The energy resolution is depending on detector type, size and operation temperature. Values measured for MnK vary between 128 eV and 150 eV at -20^oC.

The radiation entrance window of the detector is homogenous and has been optimized for a high sensitivity either in the low X-ray energy range (< 500 eV) or by an antireflective coating for optical (scintillator) light.

The SDD is used in XRF applications for material analysis and quality assurance. In this area the detector profits from its good energy resolution, the high count rate capability and the good ratio of detector price and performance. Also the Synchrotron Radiation applications rely on the high count rate capability of the device. The large area variants (20 to 30 mm²) are interesting for TXRF. The high resolution type SDDs - either type SD3 or type PSD - are most relevant as EDX detectors in Microbeam Analysis (SEM) especially in clean room ambients where liquid nitrogen service is not allowed. In combination with a scintillator the SDD is used as gamma detector.

The pn-SDD is mounted and bonded into TOX housings. Cooling is easily performed with a peltier element down to -20^oC.

Read out of the detector is possible in the classical source follower mode or via a feedback capacitance in the CSA mode. For resetting either the self resetting mechanism of the detector or a pulsed reset can be used.

The detector principle of the pn-SDD is described in detail under Detectors and in the Literature.

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Detector Types:

The SDD is available

	in its classical round shape (SDD) in sizes between 5 and 30 mm2 esp. dedicated to high count rate applications with shaping times of 125 - 500 ns and energy resolution of typ. 140 eV
	in the droplet shape (SD3) in sizes of 5 and 10 mm2 esp. dedicated to high resolution purposes with energy resolution of 128 to 138 eV and high peak-to-background of 10.000
	in polysilicon technique (PSD) in sizes of 10 to 30 mm2 esp. dedicated to easy mounting and bonding with excellent energy resolution between 128 eV and138 eV

For further details consult Detectors or the Selection List. For Multicell Structures look there. For availability and prices contact Sales Information.

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Terms of Delivery:

The detectors are generally sold as chips to OEM customers.
For packaged modules ask sales information.

The chips are individually electrically measured and optically inspected. The spectroscopic performance as

• energy resolution
• peak-to-background
• stability and radiation hardness

is deduced from sample chips which are mounted and tested continuously in our
qualification line.

The mounting line of drift detectors. First the detectors are mounted and bonded to substrates, then glued onto peltier elements and sockets, finally closed and tested.

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Mounting Support:

We support the mounting and bonding issues of our customers by

• detailed information and experienced advise
• training courses
• and hardware delivery (as peltiers, sockets).

Substrates (ceramics) for mounting and bonding the chips are provided on a regular basis for all detector types.

For qualification we send out mounted modules.

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Electronic Read Out:

In all SDDs the first amplification step (transistor) is integrated into the device.
To read out the detector various possibilities are provided:

• Classical Source Follower Configuration:
  A constant current is fed into the source of the integrated FET. A change in the anode potential gives rise to a change of the source potential which is ac-coupled to a standard charge sensitive amplifier. The anode is discharged by an automatic self-adapting reset mechanism. In this regime the signals have a rise time of typ. 200 ns and exponential decay.
   
• Charge Sensitive Amplifier:
  To use the SDD in a classical charge sensitive amplifier (CSA) configuration inner guard ring can be used as feedback capacitance. The value of the feedback capacitance is app. 30 fF.
   
• Reset Mechanism:
  For working point stabilization either the avalanche self reset can be used or the anode potential can be controlled externally by the reset diode.

We support the development of the read out electronics of our customers by detailed information and experienced advice. For further details contact Sales Information.

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