These pages contain rules and supporting information on safety for labs P422, P423A, P427 and P424. You MUST abide by all Departmental and University H&S policies: please consult the relevant pages (e.g. via Moodle for your final year project). This information will help you work efficiently and safely, and may be useful for compiling and updating your risk assessments. The group's general risk assessment is here. You must report ALL accidents and near-misses properly including all accidents to a Departmental First Aid contact.
Emergencies: the general rule for UHV systems, in the event of fire, flood or power cut, is DO NOTHING. If you have to evacuate the building, shut down high voltage power supplies and effusion cells if you can but do not delay evacuation - your personal safety comes first. Non-expert users should not attempt to do anything to UHV systems. Expert users: unless you are absolutely sure what you are doing, just leave the UHV systems. You may cause more problems that you solve by intervention.
Note: captioned pictures are here
Samples and chemicals.
Please do NOT leave unlabelled beakers and samples around. You are responsible for storing your samples sensibly with a suitable labelling and record system. Use the fume cupboard in P426 when needed, e.g. for working with HCl etches. The group's chemical inventory is here
- Make sure you have checked safety data sheets for all chemicals you are using. Help on interpretation.
- Prepare all your chemicals for an etch / clean experiment at once; dispose of them at the end properly.
- You can get deionised water from P155. Use properly labelled containers.
- Dispose of solvents in the waste solvent container in P426 (we use mainly acetone and isopropanol).
- Dispose of PEI and other special chemicals in dedicated waste containers in P423A or P426.
- Acid can be diluted and flushed down the sink (we use mainly hydrochloric acid). Add acid to water.
- If you use sulfuric acid (rarely done in our standard cleans), take extra care!
- Wash bottles can be kept in in labs for small cleaning jobs (don't overfill and you must store in drip trays). Never put a chemical in a wash bottle other than that which is displayed on the bottle.
- Do NOT touch effusion cells or MBE source materials (e.g. stored under nitrogen in the glove box) without consulting me. The cells may contain material such as arsenic, antimony and samarium in powder form. I will supervise ALL work outside vacuum with effusion cells.
- SPILLS: solvents can be mopped up with lots of lab tissue paper (allow paper to dry in fume hood, wear gloves) or left to evaporate with a clear NO ENTRY sign on the door. In the event of a large solvent or chemical spillage, we have face masks with suitable filters to deal with most situations. Should you have a large spill outside a fume cupboard, please be aware that these resources are available within the department. Please contact John Horsler in the first instance should you need to use these resources.
Training on equipment.
You may NOT use any equipment unless you have been trained by me and this training has been signed off
. This means ALL the MBE chambers and thin-film evaporators (vacuum systems in P422 and P424) as well as the Hall measurement system, Kelvin probe system, UV ozone cleaner and spin coater (all in P423A).
We use small amounts in non-pressurised containers. Your must be trained in handling, decanting and transporting liquid nitrogen before using it. The group's liquid nitrogen risk assessment is here
General good practice.
- Tidy away tools, samples and chemicals every day. No cluttered benches / desks thank you!
- Update system log books every day of use please.
- Sometimes we need to lift awkward pieces of kit (electronics, manipulators, etc.) - plan these operations, use appropriate PPE (e.g. safety boots, gloves) and consult the University's advice here. If you are not sure about any manual handling task, ASK for help. We have a small dolly (wheeled platform) which is useful for rotary pumps. We have a sturdy metal trolley, but for items heavier than 20 kg or so use a truck from stores.
- Keeping cables tidy is a must. Not only can sloppy cable runs generate electrical and trip hazards, but consider that a sideways pull on a ceramic feedthrough can vent a UHV chamber catastrophically!
- Keep sharp tools safely e.g. razor blades in foam blocks. Sharp waste goes in the yellow sharps bin in P423A.
- Use lab coats and safety goggles / glasses for ALL wet chemistry. Wear gloves when handling ANY material for use in vacuum (samples, UHV equipment, crucibles, sample carrier plates).
Oven and hot air blower. We sometimes use these (along with dry nitrogen) to dry samples or equipment which has been cleaned. Obviously, do not use the oven for food! Place a label by it when in use: we may dry at <100°C overnight for instance. The hot air gun can generate VERY high temperatures - use with caution, it is nothing like a hair-dryer! Make sure hot items are left to cool in a sensible place and a WARNING is displayed. Use the gauntlets or thermal protection gloves (with bright yellow backing and bobbly rubber grips) to handle hot items.
Cleaning for vacuum.
We use Micro-90 for general cleaning
often with ultrasonic cleaning. This is a safe cleaning agent (dispose down the sink) but do NOT use it on aluminium! You just need a few drops in a beaker. The big ultrasonic cleaner is noisy - do NOT use when people are working in the lab. Here is guidance on noise and ultrasound
. The small (newer) one is preferable unless you need a long high-power clean. Rinse with water. You may want to go on to a solvent clean before blowing dry with nitrogen and / or heating in air (see above). Always wear gloves. For MBE samples we want to avoid dust contamination so the laminar flow cabinet in P422 is the preferred bench for final stages.
Liquid nitrogen. We use very little liquid nitrogen these days (e.g. for Hall measurement). However, you must be trained in decanting and handling liquid nitrogen by an approved member of the department. We normally use hand-held flasks or our small non-pressurised wheeled dewar stored in P427.
High pressure gases.
We use small gas bottles (1 litre, 12 bar) for most applications these days but there are some larger cylinders in P422 (argon, hydrogen) and P424 (2 hydrogen). Do NOT fiddle around with regulators - if you are unsure about how to operate them or suspect there is a problem, consult me or Alan Burton. You must be trained in gas admittance to vacuum systems
. Further guidance is available here
The CVD systems in P424.
These are the tube furnaces by the windows. They can be HOT and are connected to high pressure gases (the large bottle is hydrogen) so do not touch! Safety details are on a separate page
. If you think there is a problem alert Dr. Neil Wilson
Storage in P427. Take care with manual handling. Store items SAFELY (make sure they can't fall out / topple over / etc.) and IN THE PROPER PLACE. For example, don't just bung vacuum fittings back into drawers randomly, keep them properly sorted!
UV ozone cleaner in P423A.
The intense UV is completely retained in the unit but ozone is generated, so it is connected to the extract pipe (and out via the fume hood). If you smell ozone
switch off the machine, vacate the lab and put a warning on the door. Note: you should use a mask with ozone + particulate filters to go in the lab after a suspected ozone release. Filters are kept in P424 along with a Do Not Enter sign. Ozone exposure information is available from HSE
The UV ozone cleaner, UV LED within the Quantum Yield chamber (P423A) and UV lamp on Morbius keep all UV light safely contained. We may use UV sources (LED, deuterium lamp, pond cleaner) in the lab. You MUST keep all UV sources safely screened, e.g. within the Kelvin Probe's Faraday cage, and provide suitable signage. Discuss and separately risk-assess all such UV experiments with me, Alan Burton or Yorck Ramachers before using UV sources outside these designated areas. HSE guidance
on UV. UV protective safety specs are available in the PPE drawer: use them whenever your eyes might be exposed to UV, e.g. setting up a new experiment with UV LEDs. You should also wear disposable gloves: UV can damage skin too.
The leak-checker. This is kept in P423A and can ONLY be used by trained staff/students. Please sign it out and back in with me and/or Mike Crosbie. You MUST NOT use the leak checker to pump any system which may expose it to significant levels of toxic or harmful materials. You MUST fill in the log book so that Mike or I can sign off to the manufacturer that it has not been exposed to dangerous chemicals for its annual service.
Do NOT prop open fire doors, or place wedges or other obstructions around fire doors or any adjacent half doors as illustrated below.
Fire door and half door in correct positions.
NOT allowed – fire half door left open.