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 updated on the Surface Group Teams file space.

• 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 (now NOT used 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 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. Contact a member of technical staff.

Training on equipment. You may NOT use any equipment unless you have been trained by me and this training has been signed off. The training record and competency summary are kept in the Surface Group Teams file space. This covers ALL the vacuum chambers in P422, P423A, P427 and P424 as well as the equipment in P423A. You are required to keep track of what procedures you have been trained in: you can append this to your risk assessment as a grid, for example.

General good practice. 

• Tidy away tools, samples and chemicals every day. No cluttered benches / desks thank you!
• When leaving samples and chemicals on a bench or in the glove box or laminar flow cabinet, please label everything clearly.
• Keep track of samples inside vacuum systems with our post-it / whiteboard system.
• 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 - only close these up when FULL.
• 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).
• Sometimes you need to reach a high shelf or perform an operation at moderate height. Only use a proper step - several are available in the group (short ladder, wide step, "Daleks") - and follow this guidance.

III-V wafer handling. GaAs is a hazardous material (H410 - Very toxic to aquatic life with long lasting effects;
H301 + H331 - Toxic if swallowed or if inhaled) and other III-V materials are similar. Best practice when cleaving (cutting) samples is to wear a dust mask to eliminate the small chance of inhaling GaAs dust. The mask also helps to prevent build-up of exhaled water vapour on the sample surface. You should only cleave material when you have been shown how (using glass slides and diamond scribe). Use tweezers to handle wafers to prevent surface contamination. Dispose of wafer in the labelled waste wafer containers in P422 / P423A ONLY. If a sample is dropped and shatters make sure all fragments are collected for safe disposal.

Arsenic. We use arsenic in the UHV systems Morbius and MADGE, and occasionally in Mini-Me for testing. You may NOT use arsenic in these machines, nor may you participate in venting of the relevant chambers, unless you have been trained in Safe working with arsenic in vacuum by Gavin Bell, and read this leaflet from HSE.

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... The temperature gauge shows when it is in use. The yellow 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.

Spot welding. The spot welder in P422 is used to attach samples to sample plates by welding on Ta wire across the corners of the sample. It is also used for minor repairs and thermocouple welding. You may NOT use it unless properly trained. It should NOT produce bright flashes when working properly. If it is sparking, either the electrodes are contaminated (clean with a file or SiC paper) or your sample plate has an insulating oxide layer. You MUST wear eye protection (tinted safety glasses) in case of a spark coming off towards your face. There is a separate RA available. Standard setting for Ta wire welds to sample plates: LEVEL = Medium, POWER dial approximately 11 o'clock.

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 (or Zn or Mg)! You just need a few drops in a beaker. The ultrasonic cleaners can be noisy - please avoid 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 or cooling manipulators on Morbius and MADGE). 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. Here is the group liquid nitrogen risk assessment.

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 Professor 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.

UV sources. 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, torches) in the lab. You MUST keep all UV sources safely screened, e.g. within the Kelvin Probe's Faraday cage, and ensure the signage is up to date. 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 and University guidance. 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 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 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.