A free-standing thin foil bolometer for measuring soft x-ray fluence

Area of Science:

• Plasma Physics
• Diagnostics

Background:

• Z-pinch experiments generate intense soft x-ray radiation.
• Accurate measurement of soft x-ray fluence is crucial for understanding these phenomena.
• Existing bolometers with substrates can be affected by heat loss.

Purpose of the Study:

• To develop and characterize a free-standing thin foil bolometer for soft x-ray fluence measurement.
• To validate the bolometer's sensitivity using multiple calibration methods.
• To compare the performance of free-standing bolometers with those on substrates.

Main Methods:

• Development of a free-standing thin foil bolometer.
• Determination of bolometer sensitivity through multiple calibration techniques.
• Comparative analysis of waveforms between free-standing and substrate-mounted bolometers.
• Quantitative analysis of heat loss effects using simulations.

Main Results:

• Consistent sensitivity values obtained from different calibration methods.
• Demonstrated validity and reliability of the free-standing bolometer's sensitivity.
• Observed significant differences in waveforms due to substrate heat loss.
• Highlighted the necessity of considering heat loss for substrate-mounted bolometers.

Conclusions:

• The free-standing foil bolometer offers a reliable method for measuring soft x-ray fluence in z-pinch experiments.
• Direct Joule heating calibration is effective and avoids corrections needed for substrate-based devices.
• Heat loss to the substrate is a critical factor affecting measurements from substrate-mounted bolometers.