Detector XR-100SDD

The XR-100SDD is a thermoelectrically cooled silicon drift detector (SDD), preamplifier and cooling system. The temperature of the components is maintained at approximately -55 ^o C and is monitored by a built-in temperature sensor. The TO-8 hermetically sealed housing has a light- and vacuum-tight thin beryllium window that allows soft X-rays to pass through.

1_____XR100__PX5

Fig.1 Silicon drift detector in XR100 and PX5.

2____SDD

Fig.2 Silicon Drift Detector (SDD)

The XR-100SDD features advanced X-ray detection technology previously only available commercially in expensive cryogenically cooled systems.

Resolution 125eV (full width at half maximum) at 5.9keV energy;
High signal-to-noise ratio of 20,000:1;
High counting speed - 500,000 measurements per second;
25 mm ² x 500 microns;
Multilayer collimator;

Lack of liquid nitrogen

3__55Fe______SDD

Fig.3 Spectrum of 55Fe obtained on a silicon drift detector (SDD)

General information

The high quality of these detectors, their small size and low cost make them ideal detectors for portable OEM applications on benchtop analyzers. The Silicon Drift Detector (SDD) allows for extremely high count rates with excellent energy resolution. This detector is housed in a TO-8 enclosure like other detectors manufactured by Amptek, so it is fully compatible with all Amptek products.

A silicon drift detector (SDD) is a type of photodiode that is similar in function to a PIN photodiode but has a unique electrode structure. Amptek SDD detectors are ideal for X-ray spectroscopy.

The key advantage of the SDD detector is that it has a significantly lower capacitance than conventional diodes of the same area, thereby reducing the level of electronic noise. For X-ray spectroscopy, the SDD has better energy resolution while operating at much higher count rates than a conventional diode. The SDD uses a special electrode structure that directs electrons to a very small, low-capacitance anode.

Characteristics

General
Detector type	Silicon Drift Detector (SDD)
Detector size	25 mm ²
Silicon thickness	500 µm, (see efficiency curves)
Collimator	Multilayered
Energy resolution at 5.9 keV ( ⁵⁵ Fe)	125 - 140 eV (width at half maximum)
Signal to background ratio	20,000:1 (counting ratio from 5.9 keV to 1 keV)
Thickness of beryllium glass	0.5 mil (12.5 µm) or 0.3 mil (8 µm), (see transmission curves)
Collimator	Internal multilayer collimator (ML).
Charge sensitive preamplifier	Standard Amptek Preamplifier
Gain stability	<20 ppm/°C
XR100SDD overall dimensions	7.6 x 4.4 x 2.9 cm
XR100SDD weight	125 g
Total power	<2 W
Warranty period	1 year
Service life	5 - 10 years, depending on consumption
Working conditions	From 0°C to +50°C
Storage and transportation	Long term storage: 10+ years in dry place Standard conditions: -20°C - +50°C, 10 - 90% humidity without condensation
TUV Certification Certificate #: CU 72072412 02 Tested: UL 61010-1:2004 R7 .05 CAN/CSA-C22.2 61010-1: 2004
Input parameters
Preamplifier power supply	±8 - 9 V at 15 mA with peak-to-peak noise <50 mV
Detector power supply	-95 to -160 V at 25 µA
Cooling power supply	Current = 350 mA max, voltage = 3.5 V max, with peak-to-peak noise < 100 mV Note: The XR-100SDD includes its own temperature sensor.
Output parameters
Preamplifier sensitivity	1 mV/keV (may vary for different detectors)
Preamplifier Polarity	Positive signal (1 kOhm maximum load)
Preamplifier response	Reset
Temperature sensor sensitivity	PX5/X-123: Direct reading in K via software
Additional equipment
X-123SDD	The Silicon Drift Detector is also available in the X-123SDD configuration, which includes the detector, preamplifier, DP5 pulse analyzer, MCA devices and PC5 power supply, which is a complete spectrometer.
Vacuum equipment	SDD is compatible with all Amptek vacuum equipment
OEM	SDD is compatible with all OEM devicesAmptek

Comment

The Silicon Drift Detector (SDD) requires a negative high voltage to operate and produces a positive preamplifier signal at the output. This is different from the Si-PIN standard, which requires a positive high voltage and produces a negative preamplifier signal at the output.

The PX5 preamplifier can produce both positive and negative signals. When the PX5 is paired with the XR 100SDD, it is set to negative high voltage. Using the XR100CR Si-PIN detector with the PX5 set to negative high voltage will cause damage not covered by the warranty. Also, when the PX5 is paired with the XR 100CR Si-PIN, it is set to positive high voltage. Using the XR100SDD detector with the PX5 set to positive high voltage will cause damage not covered by the warranty.

Performance for different operating conditions.

Maximum resolution

Resolution: 125 eV(FWHM) at 5.9 keV
11.2 µs - peak time
Counting speed - 100,000 measurements per second
Peak to background ratio is 20,000:1
Resolution: 155 eV(FWHM) at 5.9 keV
0.8 µs - peak time
Counting speed - 500,000 measurements per second

Operation in portable devices

Resolution: 150 eV(full width at half maximum) at 5.9 keV
3.2 µs - peak time
Counting speed - 200,000 measurements per second
At a detector temperature of 250 K (-24 °C)

Using collimators

Most Amptek detectors contain internal collimators to improve the quality of spectrum. Depending on the detector type, collimators can:

improve signal-to-noise ratio;
eliminate edge effects;
eliminate false peaks.

Working in a vacuum

XR-100SDD can operate both in air and in vacuum at pressures up to 10 ^-8 Torr. The detector is available in different configurations for use in various systems and installations, including vacuum chambers.

4__XR-100SDD____

Fig.4 Modifications of XR-100SDD for working with vacuum

Additional system and performance information

5______

Fig.5 Graph of resolution dependence on peak time

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Fig.6 Comparison of the graphs of the dependence of resolution on peak time/settling time for Si-PIN and SDD detectors

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Fig.7 Graphs of resolution versus count rate for different peak times. The graph also shows the maximum output count rate.

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Fig.8 Bandwidth of the silicon drift detector

9__4__

Fig.9 Spectrum of 4 million measurements for Fe55 obtained using SDD detector

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Fig.10 Graphs of resolution dependence on energy for different peak time values obtained using SDD detector

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Fig.11 The figure combines the effect of beryllium glass permeability (including the protective layer) and interaction with the SDD detector. The low-energy region on the graph is determined by the thickness of the beryllium glass - 0.3 mil (8 μm) or 0.5 mil (12.5 μm), while the high-energy region is characterized by the thickness of the active zone of the SDD detector