Notice of Disclaimer:

Many of the topics, projects, and materials discussed in the Bell Jar are inherently hazardous to life, health, and property. Please do not undertake the utilization or implementation of any of the information presented herein unless you have an appropriate level of experience. While care has been taken to assure the accuracy of the material presented, neither the editor nor the contributors may be held liable for any damages and/or injuries resulting from the use or misuse of information.


Treat all glassware under vacuum with respect. Safety glasses should be worn at all times to protect your eyes from flying glass should the glassware break and implode. Large glass vessels should be screened with a suitable protective screen. A piece of polycarbonate plastic (e.g. Lexan) is satisfactory. Before each use, check all vacuum glassware for scratches, cracks, chips or other mechanical defects that could lead to failure. Consult a qualified technical glassblower concerning repairs of damaged glassware.

High Voltage and X-rays:

High voltage experimenters are naturally drawn to vacuum because of the many interesting phenomena that may be studied in vacuum. High voltage safety is discussed in a number of amateur oriented publications such as the ARRL's "Radio Amateur's Handbook." An additional concern is the generation of x-rays by high voltage discharges in evacuated vessels. While not a great concern in rough vacuum conditions and voltages of 10 kV or so, higher voltages at milliTorr level pressures can produce harmful levels of x-rays under certain conditions. A simple radiation monitor should be available to check your experiments for radiation. When working with devices intended to produce radiation, a regular dosimetry program should be maintained by the experimenter in order to monitor dosage over time.


Be careful with used equipment. Responsible suppliers will decontaminate equipment that has been exposed to process gases and chemicals but I have seen a number of instances where contaminated equipment has been on a surplus dealer's shelf. Be especially careful with components that may have been used downstream of a process chamber (throttle valves, traps, isolation valves, pumps) as these will collect process residuals. Ask for evidence of decontamination.

Disposal and Recycling:

Please abide by applicable laws and regulations when disposing of vacuum equipment. This would include mercury-containing gauges, contaminated pump oils, etc.

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