AMPTEK XR-100 X-Ray Detector User Guide
- October 30, 2023
- AMPTEK
Table of Contents
Amptek X-Ray Detector Selection Guide
Overview
Amptek provides a family of high performance, compact X-ray detectors and
associated signal processing electronics. The radiation detectors are custom
photodiodes, including the traditional Si-PIN diodes, Silicon Drift Detectors
(SDDs), and CdTe Schottky diodes. The detector is mounted on a two-stage
thermoelectric cooler along with the preamplifier’s input transistor.
The cooler keeps the detector and transistor at -25 oC or below, reducing
electronic noise without cryogenic liquid nitrogen and drawing <1W. This
cooling permits high performance in a compact, convenient package, and has
been critical to the development of portable XRF analyzers and of high
performance, bench top XRF and EDS systems.
Amptek’s detectors represent the state-of-the-art in X-ray spectroscopy,
delivering the best energy resolution, best efficiency at low energies,
highest count rates, highest peak to background ratios, all at low cost and
suitable for portable systems, vacuum systems, etc. They are used by OEMs and
by laboratory researchers. The core enabling technologies include the
detectors themselves (which are designed and manufactured by Amptek), CMOS
technology, and the packaging which enables good cooling in a robust system.
Amptek has several different basic detectors in this family, sharing the core
technology but optimized for different applications.
The sketch above illustrates a detector mounted on a thermoelectric cooler, on
a TO-8 header. The input FET and other components are also mounted on the
cooler. A nickel cover (also shown) is welded to the TO-8 header with vacuum
inside the enclosure for optimum cooling. In the cover is a window (shown
green above) to enable soft X-ray detection. This is typically beryllium for
energies > 2 keV, with Si3N4 available for lower energies. The detectors use
reset-style preamplifiers.
The Detector Element
Detector Selection
FAST SDD®: This is Amptek’s highest performance detector. The FAST SDD® is
recommended for users needing the best performance. It can provide the best
energy resolution (down to 122 eV FWHM at 5.895 keV), can measure the lowest
energy X-rays (down to the Li Ka line at 52 eV), has the best peak to
background ratios, can run at the highest count rates (> 1 Mcps), and is
available at the largest areas (up to 70 mm2). The FAST SDD® is widely used in
the most demanding XRF applications, in EDS and SEMs/TEMs, in synchrotrons,
and other research systems.
Si-PIN: Recommended for applications requiring moderate energy resolution and
count rate, where cost is most important. Si-PIN devices have a conventional
planar structure, yielding more electronic noise than an SDD but are easier to
fabricate. There are three different Si-PIN variations currently available,
with areas of 6 mm2, 13 mm2, and 25 mm2. The 6 mm2 detectors provide an energy
resolution of 140 eV FWHM at the 5.9 keV Mn Ka line at count rates up to 50k
cps. The 13 mm2 and 25 mm2 detectors typically offer energy resolutions of 180
and 210 eV FWHM for the same count rates.
CdTe: Recommended for applications above 20-30 keV. CdTe has much higher
stopping power than Si and can be made much thicker, so has high efficiency
for all characteristic X-rays, even up to the K lines of U. The electronic
noise of CdTe is worse than that of either Si detector (resolution typically
450 eV FWHM at the 5.9 keV Mn Ka line), making a Si detector a better choice
for energies below 20 keV. But above 20 to 30 keV, the resolution is dominated
by Fano broadening anyway so the difference becomes small, the characteristic
X-ray lines are more widely spaced, and the efficiency of the Si detector
falls off, making CdTe a better choice. The CdTe detectors is very well suited
to measuring the spectrum from an X-ray tube, where efficiency is very
important and energy resolution is less critical. CdTe is also the best choice
for Gamma- Ray applications.
Configurations
All Amptek x-ray detector elements are available in the XR-100, X-123, or OEM
configurations.
The XR-100 configuration includes the detector and preamplifier only and must
be paired with the PX5 Digital Pulse Processor, MCA, and Power Supply to be a
complete system (or the DP5/PC5 OEM processor and power supply). The
XR-100/PX5 combination is the most flexible and is designed for laboratory and
research use. The PX5 can be used with other detectors, including from other
manufacturers.
The X-123 includes the detector, digital pulse processor, MCA, and power
supply all in one box, and is a complete system. The X-123 configuration is
ideal for OEM bench-top and custom applications where size, portability, and
speed to market are considerations.
For hand-held and custom OEM applications, other configurations are available.
Si-PIN & FAST SDD® Selection Table
Detector Type Area / Thickness Window Options| Guaranteed Energy Resolution eV
FWHM @ 5.9 keV
Peak to Background Ratio| XR-100 Part Number| X-123 Part Number
---|---|---|---
Si-PIN
6 mrn2/ 500 pm
0.5 or 1.0 mil Be| 139 – 159 eV
32 ps Peaking Time
P/B Ratio: 19000/1 (typical)| XY-FSG32MD-G3SP (1 mil Be) XY-FSG32MD-G2SP (0.5
mil Be)| ZY-FSG32MD-G3SP (1 mil Be) ZY-FSG32MD-G2SP (0.5 mil Be)
Si-PIN
13 mm2/ 500 pm 1.0 mil Be| 180 – 205 eV
32 ps Peaking Time
P/B Ratio: 4100/1 (typical)| XY-FS432MD-G3SP (1 mil Be)| ZY-FS432MD-G3SP (1
mil Be)
Si-PIN
25 mm2/ 500 pm 1.0 mil Be| 190 – 225 eV
32 ps Peaking Time
P/B Ratio: 2000/1 (typical)| XY-FSJ32MD-G3SP (1 mil Be)| ZY-FSJ32MD-G3SP (1
mil Be)
FAST SDD 0
25 mm2/ 500 pm 0.5 mil Be, C1, or C2 Si3N4| –
122 129 eV
4pis Peaking Time
P/B Ratio: >20000/1 (typical)| XY-HSH3AMD-G2SP (0.5 mil Be) XY-HSH3AMD-UOEA
(C1)
XY-HSH3AMD-E6EA (C2)| ZY-HSH3AMD-G2SP (0.5 mil Be) ZY-HSH3AMD-U0EA (C1)
ZY-HSH3AMD-E6EA (C2)
FAST SDD®-70
70 mm2/ 500 pm
0.5 mil Be or C2 Si3N4| 123 – 135 eV
4 ps Peaking Time
P/B Ratio: >20000/1 (typical)| XY-HS63AMD-Y2SP (0.5 mil Be) XY-HS63AMD-W6EA
(C2)| ZY-HS63AMD-Y2SP (0.5 mil
Be) ZY-HS63AMD-W6EA (C2)
*All results are under full detector cooling; please Contact Us to discuss guaranteed performance under different operating conditions. The Peak to Background (P/B) Ratio is the ratio of counts from 5.9 keV to 2 keV for 13 and 25mm2 Si-PIN, and 5.9 keV to 1 keV for all SDDs and 6 mm2 Si-PIN.
Resolution vs. Peaking Time for Amptek Si-PIN and SDD Detectors
AMPTEK, INC. 14 DeAngelo Drive, Bedford
MA 01730-2204 USA
+ 1 781 275 2242 Fax + 1 781 275 3470
Amptek.sales@ametek.com
www.amptek.com
References
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