VIAMP
The VIAMP preamplifier modules are specially designed printed circuit boards for operation with KETEK’s VITUS Silicon Drift Detectors (SDD). The assembly comprises an ultra-low noise, ramped reset type electronic preamplifier of positive polarity with onboard settings and filtering for all necessary SDD bias voltages.
Depending on the size and application of the SDD module, three standard Aluminum housing options are available for the electronic boards, which provide appropriate protection and serve as a sufficient heat sink.
VIAMP-KC 3.0
VIAMP-KC 3.0 with standard housing for VITUS modules H7 to H50
Unique Features
- Ultra-low noise preamplifier
- Ramped output, positive polarity
- Low power consumption
- Available with Graphene based VITUS SDDs
- Improved quantum efficiency for higher energies in combination with VICO-DV 3.0 with KETEK DPP3
- Flex lead connection lengths from 50 mm to 200 mm
- OEM solution for mobile XRF applications
- Guaranteed energy resolution for Mn-Kα-line: FWHM < 133eV @
1 μs peaking time and −35 °C SDD chip temperature - Guaranteed peak to background > 15,000, typical > 20,000
- Other housing designs on request
VIAMP-KC 3.0 with a VITUS H50 CH and a VITUS H20 CH module, also with CL graphene window available
VIAMP-KC 3.0 with a VITUS H20 CH module, back view
VIAMP-KC 3.0 with VITUS H20 CH module and with a VICO-DV 3.0 complete electronics board with DPP 3.0
Option without housing: VIAMP KE 3.0 with a VITUS H20 CH module, front view
Specifications
| First amplification stage | KETEK CSA |
| Energy resolution (@ Mn-Kα, -35 °C chip temperature and 1 µs peaking time) | ≤ 133 eV |
| Peak to background | > 15,000 |
| Peak to tail | > 2,000 |
| Peak shift stability up to 100 kcps | < 1 eV |
| Max. input countrate | 2,000 kcps |
| Graphene CH window
Graphene CL window |
1 μm Carbon
165 nm Carbon |
| Cooling performance at +20 °C heat sink temperature |
∆T > 85 K |
Spectrum
The spectrum has been acquired in KETEK’s standard end qualification test stand with an Fe-55 source. The input count rate has been 50 kcps at a peaking time of 1 μs and a SDD chip temperature of -35 °C. The spectrum shows an excellent energy resolution for Mn-Kα and peak-to-background ratio.
Energy Resolution
This plot shows the energy resolution for Mn-Kα measured with a VIAMP-KC 3.0 and KETEK DPP3 at different peaking times from 25 ns to 8 μs at a SDD chip temperature of -35 °C. The best set of parameters depend on the application optimizing either the energy resolution or the achievable through put.
Operating Parameters
| Parameter | Typical | Maximum Ratings |
| Positive Power Supply DC | +5 V 18 mA |
+4.9 V to +5.4 V 22 mA max |
| Negative Power Supply DC | -5 V 8 mA |
-5.4 V to -4.9 V 12 mA max |
| Output Signal | Positive Ramp | |
| Output Amplitude | ±0.975 V | ±0.95 Vpp,min ±1.0 Vpp,max |
| Output Gain* | 5 mV/keV | ±20 % |
| Gain Stability | < 20 ppm/°C | |
| External Reset (VICO-DV 3.0) | 0 V or + 3.3 V | |
| HV Supply DC | -168 V ≈ 95 µA |
±5 V 110 µA max |
| TEC Supply DC | 157 mA / 1.58 V @ -35 °C | 500 mA / 7 V |
| TEC ∆T | > 85 K @ +20 °C heat sink temp. | |
| Temp. Sensor | 10 kΩ Thermistor @ +25 °C | ≤ 1 µA |
| *other gain on request |
Operation Block Diagram
FFC connection
8-Pin FFC
VIAMP communication with VICO-DV 3.0 supply electronics
FFC Cable Length
The flat flexible cable is available in 50 mm, 100 mm and 200 mm length.
Pin Assignment 10-Pin FFC
| Pin 1 | TEC Return |
| Pin 2 | TEC Supply |
| Pin 3 | Positive Supply |
| Pin 4 | Negative Supply |
| Pin 5 | GND (Signal Return) |
| Pin 6 | Signal Out |
| Pin 7 | Temperature Sensor |
| Pin 8 | GND |
| Pin 9 | Not Connected |
| Pin 10 | HV Supply |
Geometry
Grounding and Thermal Scheme
The VIAMP needs to be mounted using a gap pad which is electrically isolated but thermally conductive, as the VIAMP housing functions as heat sink.
Temperature Read-out
The temperature of the SDD chip is determined by a thermistor with a resistance-temperature correlation according to the following equation:
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