Detailed performance depends on detector and configuration, which can be optimized for special applications.
X-123 represents the culmination of 14 years of X-ray detector development at Amptek. Our philosophy has always been to create small, low power, high performance instruments while keeping them simple to operate. The X-123CdTe exemplifies this philosophy by providing in a single package the XR100T-CdTe X-Ray and Gamma-Ray Detector and its Charge Sensitive Preamplifier; the DP5 Digital Pulse Processor with pulse shaper, MCA, and interface; and the PC5 Power Supply. All that is needed is a +5 Volts DC input and a USB or RS232 connection to your computer.
Amptekís specialty is X-ray and gamma-ray spectrometers, which are small, low power, high performance, and simple to operate. The X-123CdTe combines in a single package Amptekís standard, high performance X-ray spectroscopy components: the XR100T-CdTe detector and preamplifier, DP5 digital pulse processor and MCA, and PC5 power supply. The result is a complete integrated system which can fit in your hand. In many commercially available systems, the preamplifier alone has more size, mass, and power than this integrated system. It requires only 2 connections to run: +5 VDC power and a standard RS-232 or USB bus. With the X-123CdTe, anyone can rapidly obtain high quality X-ray and gamma-ray spectra.
X-rays & gamma rays interact with CdTe atoms to create an average of one electron/hole pair for every 4.43 eV of energy lost in the CdTe. Depending on the energy of the incoming radiation, this energy loss is dominated by either the photoelectric effect or Compton scattering. The probability or efficiency of the detector to "stop" the incoming radiation and create electron/hole pairs increases with the thickness of CdTe.
The detector is mounted on a thermoelectric cooler along with the input FET and coupled to a custom charge sensitive preamplifier. The thermoelectric cooler reduces the electronic noise in the detector and preamplifier, but the cooling is transparent to the user: it operates like a room temperature system.
The pulse processor is the DP5, a digital pulse processor which replaces both the shaping amplifier and multichannel analyzer (MCA) found in most analog systems. The use of digital technology improves several key parameters: (1) better performance, specifically better resolution and operation at higher count rates; (2) greater flexibility since more configuration options are available and they are selected by software over a RS-232 interface, and (3) improved stability and reproducibility. The DP4 digitizes the preamplifier output, applies real-time digital processing to the signal, detects the peak amplitude (digitally), and bins this value in its histogramming memory, generating an energy spectrum. The spectrum is then transmitted over the DP5ís interface to the userís computer. The Amptek DP5 has 6 main function blocks to implement these functions: (1) an analog prefilter; (2) an ADC; (3) a digital pulse shaper; (4) pulse selection logic; (5) histogram logic, and (6) interfacing hardware (which includes a microcontroller) and software.
The power supply is Amptekís PC5, a single board. The input is approximately +5 VDC with a current of about 250 mA. The PC5 uses switching supplies to produce all the low voltages required for the digital processor and the preamplifier. It also includes a high voltage multiplier to produce the detector bias voltage, typically 500 V for 1 mm thick CdTe, but variable up to 750 V, and supply for the thermoelectric cooler which provides closed loop control with a maximum temperature differential of 85 °C.
The complete system is packaged in 7 x 10 x 2.5 cm3 aluminum box, with the detector mounted on an extender. In its standard configuration, only two connections are required: power (+5 VDC) and serial (either USB or RS232). The DP5 board supports several additional inputs and outputs, if the X-123CdTe will be integrated with other equipment. This includes an MCA gate, a memory buffer select signal, timing outputs, and SCA ouputs.
Figure 4. X-123 Architecture and Connection Diagram
|Energy resolution @ 122 keV, 57Co||9 mm2: <1.2 keV FWHM, typical|
25 mm2: <1.5 keV FWHM, typical
|Energy Range||5 to 150 keV. May be used at higher energy with lower efficiency, contact Amptek.|
|Maximum Count Rate||Depends on peaking time. Recommended maxima for 50% dead time with pile-up-rejection enabled are shown below.
|Detector and Preamplifier|
|Detector Type||CdTe (also available with Si-PIN or SDD)|
|Detector Area||9 mm2 or 25 mm2|
|Detector Thickness||1 mm, click here for efficiency curves|
|Be Window Thickness||4 mil (100 µm), click here for transmission curves|
|Preamplifier Type||Amptek custom design with current feedback.|
|Gain||Combination of coarse and fine gain yields overall gain continuously adjustable from 0.84 to 127.5.|
|Coarse Gain||Software selectable from 1.12 to 102 in 16 log steps. 1.12, 2.49, 3.78, 5.26, 6.56, 8.39, 10.10, 11.31, 14.56, 17.77, 22.42, 30.83, 38.18, 47.47, 66.26, 102.0|
|Fine Gain||Software selectable, 0.75 to 1.25, 10 bit resolution.|
|Full Scale||1000 mV input pulse @ X1 gain|
|Gain Stability||<20 ppm/°C (typical)|
|Peaking Time||24 software selectable peaking times between 0.8 and 102 µs, approximately log spaced, corresponding to semi-gaussian shaping times of 0.4 to 45 µs.|
|Dead Time||Total dead time is 1.05 times the peaking time. No conversion time.|
|Fast Channel Pulse Pair Resolving Time||120 ns|
|Number of Channels||Software selectable to: 8k, 4k, 2k, 1k, 0.5k, or 0.25k channels|
|Presets||Time, total counts, counts in an ROI, counts in a single channel|
|USB||2.0 full speed (12 Mbps)|
|Serial||Standard RS232 at 115.2k or 57.6k baud|
|Nominal Input||+5 VDC at 500 mA (2.5 W) (typical). Current depends strongly on detector ΔT. Ranges from 300 to 800 mA at 5 VDC. AC adapter provided.|
|Input Range||4 V to 6 V (300 to 200 mA, 500 mA max)|
|High Voltage Supply||Internal multiplier, set to 500 V, adjustable to 750 V|
|Cooler Supply||Closed loop controller with Delta_Tmax = 85 °C|
|General and Environmental|
|Operating temperature||-20 °C to +50 °C|
|Warranty Period||1 Year|
|Typical Device Lifetime||5 to 10 years, depending on use|
|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
Certificate #: CU 72101153 01
Tested to: UL 61010-1: 2009 R10.08
|USB||Standard USB Mini 1.1 jack|
|RS232||Standard 2.5 mm stereo audio jack.|
|Ethernet||Standard Ethernet connector (RJ-45)|
|Power||Hirose MQ172-3PA(55), Mating plug: MQ172-3SA-CV|
2x8 16-pin 2 mm spacing (Samtec part number ASP-135096-01). Mates with cable assembly (Samtec P/N TCMD-08-S-XX.XX-01. Top row odd pins, bottom row even pins. Top right pin = 1, bottom right pin = 2.
|DPPMCA||The X-123CdTe can be controlled by the Amptek DPPMCA display and acquisition software. This software completely controls and configures the X-123CdTe, and downloads and displays the data. It and supports regions of interest (ROI), calibrations, peak searching, and so on. The DPPMCA software includes a seamless interface to the XRF-FP quantitative X-ray analysis software package. Runs under Windows XP PRO SP3 or later. Click here for the software download page.|
|SDK||The X-123CdTe comes with a free Software Developer's Kit (SDK). The user can use this kit to easily write custom code to control the X-123CdTe for custom applications or to interface it to a larger system. Examples are provided in VB, VC++, etc. Click here for the software download page.|
|VB Demonstration Software||The VB demonstration software runs on a personal computer and permits the user to set the X-123CdTe parameters, to start and stop data acquisition, and to save data files. It is provided with source code and can be modified by the user. This software is intended as an example of how to manually control the X-123CdTe through either the USB, RS-232, or Ethernet interface using the most basic calls without the SDK. This is primarily needed as an example when writing software for non-Windows platforms. Click here for the software download page.|
Figure 5. X-123CdTe detector extender options.
For 1 mm thick CdTe and various Be window thicknesses (window dominates low energy response).
Figure 6. Log-log plot of interaction probability between 1 keV and 1 MeV.
Figure 7. Linear plot of interaction probability between 10 keV and 250 keV.
For more information on the efficiency of the CdTe detector see the AN-CdTe-001 application note.
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 9. X-123CdTe with the mounting plate and right angle bracket.
Figure 10. X-123 Mounting Plate.
Figure 11. X-123 right angle mounting bracket.
Figure 12. The X-123CdTe and Mini-X on the MP1 mounting plate.
The X-123CdTe is a compact version of the XR100T-CdTe/PX4 configuraiton. For maximum flexibility and performance see the XR100T-CdTe/PX4.
Design and performance of the X-123 compact X-ray and gamma-ray spectroscopy system.
Presented at the 2006 Room Temperature Semiconductor Detector Workshop, at the IEEE Nuclear Science Symposium.
X-123 Specifications in pdf
Digital Pulse Processor FAQ
Revised September, 2011