Dual-Grid X-Ray Source Switching Without Voltage Overshoot
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional X-ray sources face challenges in fast switching and synchronization of X-ray emission due to high voltage overshooting and undershooting, particularly with clock periods less than 1 ms, leading to inefficient dual-energy image recording and potential image impairment.
Innovation Solution
An X-ray source with a grid voltage unit that regulates the charge quantity in a capacitor by controlling the grid voltage at two separate cathodes, allowing for fast switching of X-ray emission with independent grid voltages, ensuring a constant generator current and preventing voltage overshooting or undershooting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional high voltage source is used with pulsed grid voltages for fast switching, then the X-ray source can be switched on and off quickly, but high voltage overshooting and undershooting occur particularly when clock period is less than 1 ms
Solution Approach 1:
The high voltage source is synchronized with the grid voltage clock signal and performs preliminary charging of capacitors in advance. This preliminary action allows the high voltage to be ready before the grid pulse arrives, eliminating the need for rapid voltage changes that cause overshooting and undershooting.
Solution Approach 2:
The high voltage source receives the clock signal from the grid voltage unit and uses it to synchronize its operation. This feedback mechanism ensures that the high voltage changes are coordinated with the grid voltage pulses, preventing timing mismatches that lead to voltage instability.
2Speed
If the high voltage source reacts quickly to synchronize with grid voltage, then fast switching is achieved, but charge quantities in parasitic capacitors cause flat edges in grid voltage and currents
Solution Approach 1:
Capacitors are charged in advance during the flat portion of the clock signal, before the rapid edge transition occurs. This preliminary charging ensures that when the edge arrives, the voltage changes smoothly without flat edges, maintaining both speed and precision.
3Adaptability or versatility
If conventional X-ray source switches voltage back and forth for dual-energy image recording, then material differentiation is enabled, but with low tube currents the voltage change time is relatively high resulting in low image recording frequency
Solution Approach 1:
The high voltage source performs preliminary charging of capacitors during the flat portion of the clock signal before the edge transition. This allows the voltage to change rapidly at the edge, enabling fast switching between energy levels and high image recording frequency while maintaining dual-energy capability.
4Duration of action of stationary object
If X-rays are emitted during voltage change period in conventional dual-energy recording, then continuous exposure is maintained, but unnecessary patient dose is applied and image impairment occurs
Solution Approach 1:
The synchronized operation ensures that X-ray emission occurs only during stable voltage periods when the high voltage is constant. The continuous useful action is maintained by rapidly switching between voltage levels at the clock edges, ensuring X-rays are emitted only when intended for imaging, eliminating unnecessary dose during transitions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables fast and synchronized X-ray switching with rectangular pulses, improving dual-energy image recording quality and reducing unnecessary patient dose by maintaining a constant X-ray dose application.
Implementation Method 1
a high voltage source for providing a high voltage in the high voltage cable for the acceleration of the electrons
Implementation Method 2
the high voltage source together with the high voltage cable forms a capacitor for providing a generator current
Implementation Method 3
a grid voltage unit, which has an interface for receiving a control signal and is embodied to regulate, by way of regulation of the first grid voltage at the first grid and by way of regulation of the second grid voltage at the second grid, the charge quantity available in the capacitor and thus the generator current
Implementation Method 4
a cathode facility for emitting electrons
Data Source
AI summary
One or more example embodiments relates to an X-ray source comprising a grid voltage unit including an interface configured to receive a control signal. The grid voltage unit is configured to regulate, via regulation of a first grid voltage at a first grid and via regulation of a second grid voltage at a second grid, a charge quantity available in a capacitor and a generator current as a function of the control signal.