FXE: Keep cool and carry on

To highlight the benefits of external cooling on imaging performance we have performed measurements of the X-ray focal spot position as a function of time. The results are obtained using FXE 160 nano and FXE 160 nano CT modules respectively, in the microfocus mode.

The differences between cooled and uncooled tubes on all measured time scales is immediately apparent in Fig. 1a. The size of the circles represents the spatial extent of focal spot drift after the corresponding time, which is indicated by the different colors. A cooled tube produces a five-fold reduction in spot drift, corresponding to a total drift of only 2 µm after a warmup period of 30 mins (or 6.5 µm including the warmup period). In comparison, for the uncooled tube the values are 18 µm after 30 mins warmup (or 31 µm including the warmup).

The value of this increased stability in the X-ray spot position is directly visible by comparing the test images shown in Fig. 1b and 1c. In the image taken without the cooling kit, the 2 µm dot pattern (purple arrow) is completely blurred out. The 1 µm rectangular block is not visible at all (black arrow) due to the large shift of the focal spot position. In contrast, the cooled tube produces an image where the 2 µm features are clearly resolved, and the 1 µm features are stable. Furthermore, the contrast between features is significantly increased, even for larger feature sizes of 10 µm (red rectangle).

An additional advantage of increased cooling efficiency is the increased uptime. Cooling of sensitive components removes the need for cooldown interruptions of operation. This means you can work for longer, both in microfocus and nanofocus operation modes.