Rutherford Labs double sprint race, 26 Aug

[Roger]

Entries are now open on fabian4 for the two-round sprint at the Rutherford Appleton Laboratories near Didcot on Bank Holiday Monday, 26 August. Winning times are expected to be 15-20 minutes for each round.

Don't rely too much on the photo: at least four major new buildings have been added since it was taken.

RAL_aerial.jpg (164.18 KiB) Viewed 9528 times

[nooomember]

Will the courses be going through the 'spaceship' building?

On a separate issue, I do think the term 'urban' should refer to ,classic, length courses, with sprint and park events labelled as such. I was anticipating this to have been single, regular distance courses, but not a fan of sprints so probably not going now.

[NeilC]

Looks good. How do compasses behave around the synchroton?

[Roger]

I'm not sure about compasses: I'll check, although the 'beware strong magnetic fields' signs are in places you can't get to.

However, if you're feeling a bit negative and end up in the wrong place then you may find yourself travelling rather faster* than you'd bargained for.
(*approximately 300,000 km/s)

[JK]

Looks good. How do compasses behave around the synchroton?

At Daresbury (RAL's sister lab up north) we warned people about potential anomalies. There is a lot of metal around, but I don't know if the Diamond synchrotron will be on or off during the event. For instance one person complained about a Trail-O control that he solved by "accurate compass" and we were off by 2 degrees. He then told me where he was standing and I said "beside the big Massey Fergusson" "yes, that was it" ...

Remember that any urban (sprint or otherwise) event can have you going past lumps of ferrous metal. In fact there was an anomaly 20m before the Time Control in last week's Team time control for the World Trail-O Champs - my compass moved by about 10 degrees. It was a baseball stadium so maybe there was a generator or something at that end of the ground.

Of course at least being in Oxfordshire rather than Warrington means that if you compass goes wonky at RAL you can look up in the sky at that big orangey thing that tends to migrate down there at this time of year - at Daresbury we don't often have that luxury.

[pete.owens]

... except when we set up a timed control on the roofs of buildings viewed from the north in November when the bright orangey thing was very low in the sky.

[DavidJ]

Do people ('elites' or more ordinary competitors) have time to use compasses in a sprint race? I have stopped taking one with me as I never used it.

[madmike]

Do people ('elites' or more ordinary competitors) have time to use compasses in a sprint race? I have stopped taking one with me as I never used it.

I always use it for setting the map at the start and then it is mainly a base for my magnifier for looking at ways in and out of tricky bits. A compass could also be a help if you lost contact with the map, which has been known to happen.

[Spookster]

Do people ('elites' or more ordinary competitors) have time to use compasses in a sprint race? I have stopped taking one with me as I never used it.

That's perhaps becuase most UK sprint races are urban, and you can use other features to help you run in the right direction. For sprints that are partially in forest (or just open but without street network) I think you need a compass. For example at WOC qualifiers, there was tremendous opportunity for parallel error (looking behind the wrong cottage) if you weren't sure you'd hit the right cottage by using a compass.

[AerialO]

Looks good. How do compasses behave around the synchroton?

My friend who works at Diamond says that there will be very little effect outside the building due to a. the shielding and b. the field decays at a power law much faster than inverse square, because everything is in balanced rings of 2, 6 or 8 devices that almost cancel each other out. (that's what my not-quite-as-technical-as-it-used-to-be brain remembers from the conversation at the pub, anyway.)

Remember that any urban (sprint or otherwise) event can have you going past lumps of ferrous metal.

Probably a much greater risk imho.

[Roger]

Looks good. How do compasses behave around the synchroton?

My friend who works at Diamond says that there will be very little effect outside the building due to a. the shielding and b. the field decays at a power law much faster than inverse square, because everything is in balanced rings of 2, 6 or 8 devices that almost cancel each other out. (that's what my not-quite-as-technical-as-it-used-to-be brain remembers from the conversation at the pub, anyway.)

Remember that any urban (sprint or otherwise) event can have you going past lumps of ferrous metal.

Probably a much greater risk imho.

Indeed. I wasn't expecting any effect around the Diamond synchrotron, but investigated today as promised. No discernible deviation near to the Diamond building. Tried the next to the external transformers too, but the only deflection (about 20 degrees) came from the metal fence-posts.

However, there's also an unexceptional building elsewhere on the site bearing notices 'Beware - strong magnetic field' and 'keep out if you have a pacemaker' (not a track athlete, I presume), and a small fenced-off exclusion zone outside it. Around the fence I found deviations of up to 45 degrees.

That building is rectangular so as Spookster says, few people will be relying on their compasses. I would though throw in a counter-example to his implication that compasses are not useful in urban events: what if you've got a large round building? ...

[Spookster]

That building is rectangular so as Spookster says, few people will be relying on their compasses. I would though throw in a counter-example to his implication that compasses are not useful in urban events: what if you've got a large round building? ...

Like the Gherkin, for example? Then you rely on the square square they built it in

[Roger]

Like the Gherkin, for example? Then you rely on the square square they built it in

No, larger than that: a synchrotron, say.

[graeme]

Follow the river?
or use the contours?

[Glucosamine]

Not much chance to use either rivers or countours if navigating underground at CERN or the Texan mushroom farm aka SSC. Multi-Tesla magnetic fields inside working instruments are enough to scamble brainwaves never mind compass needles. Given that leaving a compass in the wrong car glovebox can reportedly demagnetise a conventional compass (or even remagnetise 180 degrees out) - not sure about rare-earth quick needles - what short term fields would be required to impact on long term compass performance? And what fields might have an effect on SI/EMIT? Lots of interesting physics around RAL, albeit mostly contained in the buildings.