Recent content by GTrax

I will have one last try before abandoning the attempt to get a (sort of) qualitative understanding of the possible outcomes of an atom being exited into higher energy states by an incoming, sufficiently energetic photon, being more than enough to exceed all the outgoing characteristic X-ray...

It is late here (UK) right now, so references and links will have to wait. I will get back to it. There are a number of (expensive!) hand-held tools which are used in industry (and by scrap metal merchants) to produce plots of X-Ray fluorescence peaks, along with substance identification...

The few elements and their shell energies are only there for illustrative example, and a particular fluorescence for molybdenum is mentioned, but of course, there can be excitation of any elements where the incoming photon has energy higher than that required to raise the L-shell and/or K-shell...

Tentatively, I ask in this forum for a qualitative pointer to what end effects one might expect when a gamma energy photon energizes an atom of a substance, and causes fluorescence. It relates to a practical endeavour about using a PIN diode as an X-ray detector, where the device considered...

It is for this reason that our satellite tracking control software and data haul servers use Linux. When some tons of dish hardware is moving, with servo-motor and positional encoder technology required to be pointing correctly at a particular celestial time, there is no room for an OS to be...

Indeed you are right, and I get that. My apologies for perhaps not being complete enough. For example, the gyros made for Gravity Probe B were spinning spheres of niobium-coated fused quartz in orbit, with the instrument and indeed the rest of the spacecraft also in orbit "around" them, with...

This is, I think, only so because said gyroscope is supported on only one end in a fashion that it can "fall off". A fully gimballed gyroscope in partly evacuated casing keeps going for longer than 6 hours as everything around it, planet included, changes orientation.

The designs of the science fiction artists and movie makers indicate they have thought this through. Whether it be gondolas on contra-rotating arms, or an entire torus, with all the really heavy stuff kept at the axis, once it is up to speed, I don't think there is much the incumbents can do to...

As I understand it, the Plank constant was chosen as a current definition, but other natural constants can be used to provide a check, and there is definitely effort at NIST to define NA with greater precision. Avoadro's number depends on the mass of a substance, so it is easy to see why a very...

Indeed! You have it all. It seems the clock-makers have finally won! However much we (rightly) desire to to lock our measurements to quantities we perceive to be constant, we always need some physical phenomenon with such unvarying properties that we can use it as a standard. Le Grand K and it's...

Hmm.. I don't agree. I say no to Tin! Pretty much all non noble metals not protected by a surface oxide are very toxic! Especially stannous anything! Even the whole thing about replacing lead with tin in PCB solders seems to be a misplaced effort! The copper content in brass swing door handles...

Exactly! It uses what is known as a "watchdog timer" which brings the "nearly off" hibernating processor, sipping nano-amps, into life with a pulse that initiates a special boot-up that executes a few instructions to check the charge on a switch-on scheme, (did you press the switch-on button...

I seek a little help in understanding why we can see so far into the past to be able to view events where the light from these events should have long ago overtaken wherever the masses ended up. I get it that there was a considerable time during which the limits of the space expansion exceeded...

I have to try and look it up again, but years ago I was aware of a 3-set of laminated composite flywheels, these being series-connected homopolar generators which were wound up to speed, either from grid energy, or from diesel generator sets. Then, the high current pulse was made by switching...

When converting a fundamental oscillator type (like Colpitts) into one mediated by a crystal, they sometimes get developed to exploit the crystal as a narrow filter to deliver an output with very low phase noise, which is a critical feature when the output is to be used in receiver mixer stages...