Ionization Chambers AEC Sensor (VacuTec, Germany)
The Ionisation Chambers are used as sensor elements for automatic X-ray exposure control units.
They comprise air-filled parallel chambers with 1 or 3 measuring fields, coupled with an amplifier and a field selector.
The low overall thickness of 6 mm ensures the chamber may be used with all modern X-ray equipment.
Ionization Chambers for Automatic X-Ray Exposure Control
| Energy range / tube voltage | (40 … 150) kV |
| Dose rate range | (0,5 … 1000) µGy/s |
| Exposure dose range1) | (1 … 100) µGy |
| Digital resolution (selectable) | 0,025 µGy |
| Eposure time range1) | 1 ms … 10 s |
| Sensitivity difference between sensor fields | < 5% |
| Attenuation factor1) | < 1,04 |
| Aluminium equivalent | < 0,75 mm Al |
| Supply voltage (positive and negative) | ±(11,5 … 16)V DC |
| Digital output | Differential signal (RS 422), pulse width 2 µs |
| Ramp output (with ramp module) | 0 … 10 V |
| For detailed technical information please require our documents. | |
| 1) According to DIN 6815 dose measurement is carried out as follows: the air kerma (in Gy) is measured immediately downstream of the combined scattered-ray grid/measuring chamber using a radiation quality attained at a high-voltage of (70…80) kV and an Al attenuation layer thickness of 25 mm. |
 |
Click for larger schemes
Ionization Chambers AEC Sensor (VacuTec)
Application
The ionization chambers are used as sensor elements for automatic X-ray exposure control units.
They are comprised of air-filled parallel chambers with 1, 3 measuring fields, coupled with an amplifier and a field selector.
The low overall thickness of 6 mm ensures the chamber may be used with all modern X-ray equipment.
Principle of Operation
The current generated in the sensor fields by the X-rays will be amplified, digitized and fed to the Automatic Exposure Controller.
The AEC supplies the cut-off signal to the generator, and thereby ensures an optimal and reproducible image quality, independent of the radiation quality, object density and other factors.
Chamber Electronics
The ionization chambers are supplied with minimized chamber electronics, that amplify, digitize and process the generated current according to the field selection.
The electronics also generate the chamber voltage without the need for an external high-voltage source.
Ramp Modul
In order to assure the backward compatibility with conventional interfaces a separate ramp module converts the pulses into a voltage ramp.
This ramp module should be placed between the interface cable and the AEC interface on the generator site.
Chamber Types
The listed sizes of AEC chambers are supplied as a standard, but other dimensions are available on request.
The minimized chamber electronics are mounted directly on the side of the chamber. If necessary there are versions with electronics separated up to 90 cm distance from the ionization chamber.
| Type | Description | Size L2xB2 (mm) |
| 141 00 18 | 3-field chamber with electronics | 374 x 374 |
| 142 00 13 | 1-field chamber with electronics | 374 x 374 |
| 145 00 44 | 3-field chamber with electronics | 450 x 450 |
| 147 00 05 | 3-field chamber with electronics | 370 x 450 |
| 151 00 21м | 3-field chamber with electronics | 450 x 470 |
High-level Chamber
The series AEC-Sensor digital has been optimised for latest flat-panel detectors.
Chambers almost invisible measuring fields are a result of an innovative construction, which yields an extremely homogeneous X-ray absorption of the measuring chamber for all relevant tube-voltages in medical X-ray diagnostics.
Chambers thickness of 6 mm, flexibility in size and the specifications correspond to the conventional ionization chambers.
