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 | Super SDD: 25 mm2 x 500 µm Silicon Drift Detector (SDD)! | |||
| Home Page | Products | Price List | Links & PDFs | |
| Super SDD: 25 mm2 x 500 µm Silicon Drift Detector (SDD)! | |||
Silicon Drift Detector (SDD) |
136 eV Resolution!
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 Silicon Drift Detector in the XR100 and PX4. |
 Silicon Drift Detector (SDD) Element. |
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The XR-100SDD is a new high performance x-ray detector, preamplifier, and cooler system using 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. The XR-100SDD represents a breakthrough in x-ray detector technology by providing "off-the-shelf" performance previously available only from expensive cryogenically cooled systems. |
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Features
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Applications
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Performance
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The XR-100SDD Silicon Drift Detector (SDD) is the latest addition to Amptek's line of x-ray detectors that revolutionized the industry. Its high performance, small size, and low cost make it the ideal detector for OEM hand-held applications to bench-top analyzers. The silicon drift detector (SDD) enables extremely high count rate applications with excellent energy resolution. The detector is housed inside the same TO-8 package as Amptek's other detectors, so its form-factor is a direct replacement for current systems and is compatible with all Amptek accessories and options.
A silicon drift detector (SDD) is a type of photodiode, functionally similar to a PIN photodiode, but with a unique electrode structure to improve performance. Amptek’s SDDs are optimized for X-ray spectroscopy.
The key advantage of the SDD is that it has much lower capacitance than a conventional diode 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 diode. The SDD uses a special electrode structure to guide the electrons to a very small, low capacitance anode.
| General | |
| Detector Type | Silicon Drift Detector (SDD) |
| Detector Size | 7 mm2 |
| Silicon Thickness | 450 µm, See efficiency curves |
| Energy Resolution @ 5.9 keV (55Fe) | 135 - 155 eV FWHM at 9.6 µ peaking time |
| Peak to Background | 7000:1 (ratio of counts from 5.9 keV to 2 keV) |
| Background Counts | <3 x 10-3/s, 2 keV to 150 keV |
| Detector Be Window Thickness | 1 mil (25 µm),or 0.5 mil (12.5 µm), See transmission curves |
| Collimator | Internal MultiLayer Collimator (ML). Click here for more information. |
| Charge Sensitive Preamplifier | Amptek custom reset preamplifier. |
| Gain Stability | <20 ppm/°C (typical) |
| XR100SDD Case Size | 3.00 x 1.75 x 1.13 in (7.6 x 4.4 x 2.9 cm) |
| XR100SDD Weight | 4.4 ounces (125 g) |
| Total Power | <1 Watt |
| Warranty Period | 1 Year |
| Typical Device Lifetime | 5 to 10 years, depending on use |
| Operation conditions | 0°C to +50°C |
| Storage and Shipping | Long term storage: 10+ years in dry environment Typical Storage and Shipping: -20°C to +50°C, 10 to 90% humidity non condensing |
| Inputs | |
| Preamp Power | ±8 to 9 V @ 15 mA with no more than 50 mV peak-to-peak noise |
| Detector Power | -200 to -300 V @ 25 µA very stabe <0.1% variation |
| Cooler Power | Current = 350 mA maximum, voltage = 4 V maximum with <100 mV peak-to-peak noise Note: the XR-100SDD includes its own temperature controller |
| Outputs | |
| Preamplifier Sensitivity | 1 mV/keV typical (may varry for different detectors) |
| Preamplifier Polarity | Positive signal output (1 kohm maximum load) |
| Preamplifier Feedback | Reset |
| Temperature Monitor Sensitivity | PX4/X-123: direct reading in Kelvin through software. |
| Options | |
| X-123SDD | The silicon drift detector (SDD) is also available in the X-123SDD configuration. The X-123SDD configuration includes the detector, preamplifier, DP5 digital pulse processor and MCA, and the PC5 power supply. All that is needed is a +5 Volts DC input and a USB, RS232, or Ehthernet connection to your computer.
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| Vacuum Accessories | The SDD is compatible with all Amptek vacuum accessories |
| OEM | The SDD is compatible with all Amptek OEM configurations. |
The silicon drift detector (SDD) requires negative high voltage and produces a positive preamplifier output. This is the opposite of the standard Si-PIN which requires positive high voltage and produces a negative preamplifier output.
When ordered in an XR100SDD/PX4 configuration, the PX4 is equipped with a negative high voltage supply. This PX4 can therefore only be used with an XR100SDD detector. Using a Si-PIN XR100CR with a negative high voltage PX4 will destroy the Si-PIN XR100CR and will not be covered under warranty. Using an XR100SDD with a PX4 equipped with positive high voltage intended for a Si-PIN XR100CR will destroy the silicon drift detector (SDD) detector and not be covered under warranty.
Most of Amptek’s detectors contain internal collimators to improve spectral quality. X-rays interacting near the edges of the active volume of the detector may produce small pulses due to partial charge collection. These pulses result in artifacts in the spectrum which, for some applications, obscure the signal of interest. The internal collimator restricts X-rays to the active volume, where clean signals are produced. Depending on the type of detector, collimators can
The XR-100SDD can be operated in air or in vacuum down to 10-8 Torr. There are two ways the XR-100SDD can be operated in vacuum: 1) The entire XR-100SDD detector and preamplifier box can be placed inside the chamber. In order to avoid overheating and dissipate the 1 Watt of power needed to operate the XR-100SDD, good heat conduction to the chamber walls should be provided by using the four mounting holes. An optional Model 9DVF 9-Pin D vacuum feedthrough connector on a Conflat is available to connect the XR-100SDD to a PX4 outside the vacuum chamber. 2) The XR-100SDD can be located outside the vacuum chamber to detect X-Rays inside the chamber through a standard Conflat compression O-ring port. Optional Model EXV9 (9 inch) vacuum detector extender is available for this application. Click here for more information on vacuum applications and options.
Figure 2. Resolution vs. Peaking Time for the silicon drift detector (SDD).
Figure 3. Resolution vs. Input Count Rate for different peaking times for the silicon drift detector (SDD) with the DP5.
The plot also shows the curve of maximum output count rate. Operating to the right of that curve results in less throughput than the maximum despite a higher input rate. See figure 4 below.
Figure 4. Throuhgput with the silicon drift detector (SDD). Due to the detector’s smaller capacitance, a much shorter peaking time is used in the shaping amplifier without sacrificing resolution. Typically 9.6 µs or less is used. This dramatically increases the throughput of the system.
Figure 5. 55Fe spectrum with 4 million counts in the peak channel taken with the silicon drift detector (SDD).
Figure 6. Resolution vs. Energy for Different Peaking Times taken with the silicon drift detector (SDD).
Figure 7. Efficiency (linear scale) of 450 µm thick silicon drift detector (SDD) and transmission through Be winodw.
Figure 8. Efficiency (log scale) of 450 µm thick silicon drift detector (SDD) and transmission through Be window.
Efficiency Package: A ZIP file of coefficients and a FAQ about efficiency. This pacakge is provided for general information. It should not be used as a basis for critical quantitative analysis.
Figure 7. The XR100SDD and Mini-X on the MP1 mounting plate.
Silicon Drift Detector (SDD) specifications in PDF format.
Application Note AN-SDD-001: Silicon Drift Detector (SDD) at High Count Rates (pdf 500k).
Application Note AN-SDD-002: Silicon Drift Detector (SDD) Low Energy Performance (pdf 100k).
Revised November 5, 2009
