Bremsstrahlung - the best source of light

on 05 September 2012.

Synchrotron radiation of charged particles at today is the most powerful source of light (not lasers). However, the installation (accelerators) to receive synchrotron radiation expensive and bulky.

 It is possible to create an electron bremsstrahlung in a simple and user-friendly designs.
 Imagine a beam of electrons propagating in an evacuated tube. In the middle of the pipe is equipped with two electrodes (made, for example in the form of grids). The electrodes are supplied small retarding voltage. The electrons were accelerated outside the installation at a voltage much higher than the inhibitory. Let's just say for certainty, flew kilovolt electrons slowing volts maximum tens of volts.

The amount of energy possessed by the electrons before entering the brake gap will affect the process of radiation. At very low energy electrons can simply reverse the brake gap (not in this particular case 1 kV).

 If the electron passes through the braking potential difference of 1 volt, and resets the whole energy, the photon will have an energy of 1 eV. Here the question is, whether he will throw all of it or not.
 How is the energy release - the radiation? How much time? The author believes that the time of emission of a photon is equal to the wave period, T = 1 / f, where f-frequency radiation.

 

How much time will pass electronic brake gap? Obviously, the travel time will be t = (2a / w) 1/2, where a is the distance between the electrodes, w-electron acceleration.
 It is that time will determine the maximum amount of radiation T = 1 / f = (2a / w) 1/2

According to Planck's formula E = hf, then E = h (2a / w) -1 / 2

 This is the minimum energy (E min). An electron can not radiate at photon energy, because he did not have enough time for it (because of lower energy corresponds to the lower frequency, therefore, a longer period, therefore, by the author, the greater the radiation time), but the quantum of higher energy electron can emit - would create for this condition. And these conditions are determined by retarding potential. (The condition is the energy of an electron that enters a lot more braking capacity).
 On the one hand limit on the wavelength and energy leaves the stopping distance, more precisely, the time during which the electron passes the stopping distance, having a predetermined rate. On the other side of the photon energy (and hence the frequency of the radiation) should be determined by the magnitude of the braking capacity.

Емин.< Еизл.< Еторм.

h(2a/ w)-1/2< Eизл. <q(U1-U2)

Electron can emit not one, but two or more photons, if the value of the braking power is great, but for every photon to be observed this condition, and the total energy of all the photons must be equal (not to exceed) the loss of kinetic energy during braking.

 Furthermore, it should be observed, and the condition at the time of radiation, which should not exceed the time period of the electronic brake
 1/f1 1/f2 1/f3 ... 1/fp <T of passing. = (2a / w) 1/2
 So, without changing the values of the braking capacity, and changing the distance between the brake electrodes can achieve changes in the frequency of the radiation. Increasing the distance - reduce the frequency, reducing the distance - to increase the frequency.

On the other hand, does not change the distance between the electrodes, and the potential of changing the brake, you can also influence the beam: increasing the capacity-increasing frequency, reducing the potential, reduce the frequency.

 We know that in X-ray tubes emit electrons when braking a wide range of frequencies. And it is strictly limited by the high-frequency photon energy is less than Emax = hf = q (U1-U2). Lower frequencies are present, can no longer be achieved.

Clearly, the inter-electrode distance affect the spectrum, rather than a specific resonant frequency. The electrons in the beam are different enough from each other so as not to emit at the same frequency.

 In the tube noticeable bluish glow between the electrodes. Because in addition to electrons there is nothing there, then it is clear that they emit. Therefore, the statement "free electrons do not emit" for this case is not appropriate.

Thus, the electron beam can be radiating system. Beam deceleration in the electrode gap can broadly regulate the frequency of the radiation as a distance between electrodes, and the retarding potential.

In working contemporary radio and telelampah, CRT significantly a bluish glow between the electrodes.
  In a 100 watt bulb at 220 volts, the current flows in  half ampera. Luminous efficiency of 3-5%.
To compare the possible indicators of the proposed use of the light source turnkey solutions (see Devil AG, Vorobyov AA, Problems in Physics, Moscow, "High School", 1988, s.414 - this author has found new!). For example, an electron energy of 100 eV and braking capacity 55.6 in, only 4% of the electrons reflected (by the way, they also have to reject something.) 96% of the energy of the electrons will drop by half, but then the rest of the donesut to the anode (or wall) and will heat it. Therefore, more than 50% efficiency at such parameters do not get it. But in fact the figures show that, for the same light output will be possible to reduce power consumption by 10-15 times! The lamp of 10 W will give the same light output as 100 watts bulb! More so in the required portion of the spectrum! (And no one can deny to increase braking capacity and increase efficiency). Ideally, of course, the braking capacity should be accelerating voltage, but it also has a negative side: the spectral width increases, and some of it, inevitably, will jump into the invisible area.

And that's not all! Incandescent bulb shines in all directions, while the glow of the brake will be in the direction of the electron motion. That is, without a mirror and a light stream structures will be directed to one side. And the higher speed will have electrons, the smaller will be the opening angle of the cone of radiation. Cone (in fact, probably, Cherenkov?) Bremsstrahlung, focusing on the near or distant object can be adjusted in the same manner as in the flashlight.

The specific design of the author is currently the case.
In an evacuated flask is spiral bulbs (cathode). On the opposite side of the bulb is the anode. Hot cathode emits electrons that are free to reach the anode, which is arranged in a grid (or ring), and skips over it. In the space behind the anode cathode is again, but cold, not emitting electrons, also made in a grid to freely transmit light. The electrons from the hot cathode are accelerated skips anode, then decelerated second cathode and emit (reset energy). Then the electrons drift to the anode and return to the circuit. Changing the inhibitory potential (or the distance between the anode and cathode of the brake) can regulate the emission spectrum.

Let not all the electrons due to their wave properties stalled cold cathode, that they have sufficient energy to cause lyumenistsentsiyu certain substances. Covering screen for cold cathode thin layer of phosphor and can force them to give energy to the light range. As on the TV screen.

 The increase in light output lamps can afford to save so much energy that it's hard to imagine. And the energy in the world - it welfare. Not think to check design.