There are those who call it...TIM
To boldly go where people can't... The Train Inspection Monorail, affectionately referred to as 'TIM,' will allow scientists, technicians and engineers to view and take measurements in the LHC tunnel when it is inaccessible to humans.
Imagine being able to view parts of the LHC before people are allowed into the tunnel after the beam has been circulating...or to accurately measure the position of equipment in areas with the highest levels of radiation without risking human exposure. The Train Inspection Monorail, or 'TIM' to its closer friends, is a modular train that will run along the ceiling of the LHC tunnel, helping many groups on site to address the problems of inspecting, measuring and even handling equipment in the LHC when radiation levels and cryogenic hazards will restrict personnel access to the tunnel.
TIM was developed over the last year by TS-IC, the LHC Installation Coordination Group. 'What we wanted to do first of all was to demonstrate that we could communicate with a mobile device in the tunnel and control it, working with the available infrastructure,' said Keith Kershaw, who leads the effort to produce TIM. Operators communicate with TIM using the CERN mobile phone network, via a PC-sized touch-screen remote control that can be carried anywhere in the lab. TIM also makes use of the monorail I-beam that was put into place for the installation of the LEP magnets and which makes a complete ring around the 27-kilometre LHC tunnel. The team that developed TIM is building on its recent experience working on LHC cryomagnet tunnel transport and installation equipment: in addition to Kershaw, that team includes Thierry Feniet, responsible for TIM's electrical control and communication, and Jean-Louis Grenard, who designed the mechanical components of the train.
Several departments at CERN have recognized TIM's usefulness and are discussing additions to the train as it continues to be developed. TIM has already been used to visually inspect DFB current leads for condensation during the initial cool-down of sector 7-8, when personnel were not permitted to enter that section of the tunnel; two security cameras on the front and back of the machine serve as TIM's 'eyes', sending back an image of the tunnel every few seconds. In addition, Rudiger Schmidt of the hardware commissioning team has proposed to use TIM to measure radiation levels after a run, since TIM's ability to travel through the tunnel will make it possible to understand beam losses along the entire tunnel instead of being restricted measurements to the places where the beam loss monitors were installed. Doris Forkel-Wirth, responsible for LHC Radiation Protection, explained that using TIM to carry out radiation level surveys offers excellent possibilities for reducing the radiation exposure of her team. The Fire Brigade has also expressed a desire to use TIM's surveillance cameras to diagnose problems while minimizing human exposure to gas leaks or radiation. If there is a problem in the tunnel, TIM would be the first 'man' in. 'TIM can't replace fire fighter intervention,' said Deputy Fire Chief Hillebrand Bont. 'But it can give us extra information.'
New wagons will be designed and built as more users at the lab express a wish to use the machine. In its final version, TIM will work something like a miniature locomotive, with wagons that can be hooked and unhooked to the 'engine.' 'What we wanted was something that was very modular--that could change based on the requirements,' Kershaw said. The TIM modules will also form part of a train used to exchange collimators once radiation levels are too high for conventional 'hands-on' lifting and transport. Over the next few months the team plans to build a second TIM, and also to construct a mock-up of the LHC tunnel so that it can commission the trains after the LHC is sealed up. The mock-up will also allow the TS survey team to work with TIM to develop tools for measuring the alignment of the collimators precisely and remotely.
The TIM and its uses will be presented in a TS technical seminar, 'Remote inspection, measurement and handling for LHC', on Wednesday 18 April at 16h00 in the AT Auditorium, Bldg. 30.
