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silicon drift detector (sdd)
Figure 1. Silicon Drift Detector (SDD) in the XR100 and PX5.

Silicon Drift Detector (SDD)

125 eV Resolution!

All solid state design

No more liquid nitrogen!

x-ray detector element
Figure 2. Silicon Drift Detector (SDD) Element.

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.


  • 125 eV FWHM Resolution @ 5.9 keV
  • High Peak-to-Background Ratio - 20,000:1
  • Hight Count Rate - 500,000 CPS
  • 25 mm2 X 500 µm
  • Multilayer Collimator
  • No Liquid Nitrogen

Additional Information



silicon drift detector (sdd) oem applications
PA-230 housing
Silicon Drift Detector (SDD) OEM configurations.

silicon drift detector (sdd) 55fe spectrum
Figure 3. 55Fe Spectrum with silicon drift detector (SDD).

Silicon Drift Detector (SDD) Information

The 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.

Click here for more information on Amptek silicon drift detectors (SDD).


Detector TypeSilicon Drift Detector (SDD)
Detector Size25 mm2
Silicon Thickness500 µm, See efficiency curves
CollimatorMultilayer, click here for more information
Energy Resolution @ 5.9 keV (55Fe)125 - 140 eV FWHM at 11.2 µ peaking time
Peak to Background20,000:1 (ratio of counts from 5.9 keV to 1 keV) (typical)
Detector Window OptionsBeryllium (Be): 0.5 mil (12.5 µm) or 0.3 mil (8 µm), See transmission curves
C Series: Low energy windows
CollimatorInternal MultiLayer Collimator (ML). Click here for more information.
Charge Sensitive PreamplifierAmptek custom reset preamplifier.
Gain Stability<20 ppm/°C (typical)
XR100SDD Case Size3.00 x 1.75 x 1.13 in (7.6 x 4.4 x 2.9 cm) Click here for mechanical dimensions
XR100SDD Weight4.4 ounces (125 g)
Total Power<2 Watt
Warranty Period1 Year
Typical Device Lifetime5 to 10 years, depending on use
Operation conditions0°C to +50°C
Storage and ShippingLong term storage: 10+ years in dry environment
Typical Storage and Shipping: -20°C to +50°C, 10 to 90% humidity non condensing
TUV CertificationTUV Certification
Certificate #: CU 72072412 02
Tested to: UL 61010-1: 2004 R7 .05
CAN/CSA-C22.2 61010-1: 2004
Preamp Power±8 to 9 V @ 15 mA with no more than 50 mV peak-to-peak noise
Detector Power-100 to -200 V @ 25 µA very stable <0.1% variation
Cooler PowerCurrent = 450 mA maximum, voltage = 3.5 V maximum with <100 mV peak-to-peak noise
Note: the XR-100SDD includes its own temperature controller
Preamplifier Sensitivity1 mV/keV typical (may vary for different detectors)
Preamplifier PolarityPositive signal output (1 kohm maximum load)
Preamplifier FeedbackReset
Temperature Monitor SensitivityPX5: direct reading in Kelvin through software.
X-123SDDThe 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.

silicon drift detector X-123
Silicon Drift Detector in the X-123SDD Complete Spectrometer.

Vacuum AccessoriesThe SDD is compatible with all Amptek vacuum accessories
OEMThe SDD is compatible with all Amptek OEM configurations.

XR-100SDD Connectors

Preamp OutputBNC coaxial connector
Power and Signal6-Pin LEMO connector (Part# ERA.1S.306.CLL)
Interconnect CableXR100SDD to PX5: 6-Pin LEMO (Part# FFA.1S.306.CLAC57) to 6-Pin LEMO (5 ft length)
XR100SDD stand-alone: 6-Pin LEMO (Part# FFA.1S.306.CLAC57) to 9-Pin D (5 ft length)

XR-100SDD 6-Pin LEMO Connector Pin Out

Pin 1Temperature monitor diode
Pin 2-H.V. Detector Bias, -100 to -200 V maximum
Pin 3-9 V Preamp power
Pin 4+9 V Preamp power
Pin 5Cooler power return
Pin 6Cooler power
0 to +3.5 V @ 450 mA
CaseGround and shield


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.

The PX5 can produce both negative and positive high voltage. When the PX5 is ordered with an XR100SDD, the PX5 is set for negative high voltage. Using a Si-PIN XR100CR with a negative high voltage setting will destroy the Si-PIN XR100CR and will not be covered under warranty. Likewise, if the PX5 was ordered with a Si-PIN XR100CR, using a positive high voltage with an XR100SDD will destroy the silicon drift detector (SDD) detector and not be covered under warranty.

Performance for Different Operating Conditions

Ultimate Resolution

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Operation for Hand-Held Devices

Use of Collimators

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

Click here for more information.

Vacuum Operation

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 1.5 Watts 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 PX5 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.

xr100cr detector extender options
Figure 4. XR100SDD Detector Extender Options for Vacuum Applications.

silicon drift detector (SDD) beamline application
Figure 5. Custom Beamline Application with the SDD. Four (4) SDD detectors mounted on a custom flange for high count rate beamline applications.

Additional System Information and Performance

silicon drift detector (SDD) resolution vs. peaking time
Figure 6. Resolution vs. Peaking Time for the silicon drift detector (SDD).

resolution vs. peakin time for Si-PIN and SDD detectors
Figure 7. Comparison of Resolution vs. Peaking Time for Si-PIN and SDD Detectors.

silicon drift detector (SDD) resolution vs input count rate
Figure 8. 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 9 below.

throughput, input vs. output count rate for silicon drift detector
Figure 9. 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.

55fe spectrum with a lot of statistics taken with the silicon drift detector (sdd)
Figure 10. 55Fe spectrum with 4 million counts in the peak channel taken with the silicon drift detector (SDD).

resolution vs. energy for different peaking times taken with the silicon drift detector (sdd)
Figure 11. Resolution vs. Energy for Different Peaking Times taken with the silicon drift detector (SDD).

silicon drift detector efficiency and transmission
Figure 12. The figure combines the effects of transmission through the Beryllium window (including the protective coating), and interaction in the silicon drift detector (SDD). The low energy portion of the curve is dominated by the thickness of the Beryllium window - either 0.3 mil (8 µm) or 0.5 mil (12.5 µm), while the high energy portion is dominated by the thickness of the active depth of the Silicon drift detector (SDD) - 500 µm.

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.

Application Spectra

stainless steel SS316 XRF with silicon drift detector (SDD)
Figure 13. XRF of stainless steel SS316 taken with the silicon drift detector (SDD) and the Mini-X x-ray tube.

RoHS/WEEE PVC sample with silicon drift detector (SDD)
Figure 14. RoHS/WEEE PVC sample taken with the silicon drift detector (SDD) and the Mini-X x-ray tube.

CaCl2 water solution with silicon drift detector (SDD)
Figure 15. CaCl2 solution (800 ppm Ca, 1200 ppm Cl) taken with silicon drift detector (SDD) and the Mini-X x-ray tube.

sulphur in oil (1100 ppm, with KCl) with silicon drift detector (SDD)
Figure 16. Sulphur in crude oil (1100 ppm) with some KCl taken with silicon drift detector (SDD) and the Mini-X x-ray tube.

automotive catalyst with silicon drift detector (SDD)
Figure 17. Automotive Catalyst taken with silicon drift detector (SDD) and the Mini-X x-ray tube.

platinum (pt) ring xrf with the silicon drift detector (SDD)
Figure 18. Platinum (Pt) ring XRF taken with silicon drift detector (SDD) and the Mini-X x-ray tube.

Complete XRF System

xr100 and mini-x on mp1 mounting plate
Figure 19. The XR100SDD and Mini-X on the MP1 mounting plate.

XRF System Includes

Silicon Drift Detector (SDD) specifications in PDF format.

Application Notes

Application Note AN-SDD-001: Silicon Drift Detector (SDD) at High Count Rates (pdf 270k).

Application Note AN-AMP-003: Si-PIN and Silicon Drift Detector (SDD) Low Energy Performance (pdf 100k).

Application Note AN-SDD-003: Amptek Silicon Drift Detectors

Application Note AN-AMP-005: Comparison of Silicon Drift Detector (SDD) and Si-PIN Detector (pdf 70k).

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Revised July 23, 2013