I think he expects to be tried & imprisoned when an IP linked to him is found accessing such sites, and he's saying that online vigilantism will probably appear to be quite a weak defence.
I think the idea is that you need a mechanism whereby two objects close enough together to thermalize, are pushed far enough apart fast enough that they appear to be too far apart to have equalized.
Experimental accelerator physicists (not particle physicists) will come up with a conceptual design for the machine that fits the particle physicists requirements, and they will then work with engineers to design and build it.
Most of the designing and building is done by properly qualified engineers, not scientists.
If anyone else can hear that radio, I hope you've counted the number of "employee units" within earshot, and the number of half hour increments during which you play the radio, and paid the appropriate tariff.
FYI -- I work on this project, and I work with Roger Jones (the guy in the article), so I know a substantial amount about this.
Your definition of damping is quite right, but your definition of detuning is, in this case, not really what he means. What he means is taking a cavity, and changing its shape in order to "detune" some cells.
To explain:
The cavities are traditionally built in such a way that each cell rings (like a bell) at the design frequency of the accelerating rf. Since all of the cells are identical, the beam will excite exactly the same mode frequencies in each one (like a hammer hitting a bell). Since they are resonant with each other, they can and will ring coherently. Thus the amplitude of these modes will be proportional to N^2 (where N is the number of cells).
If they are made to have slight differences (detuned) that cause their resonant frequencies to be slightly different (but still within the bandwidth of each other due to their finite Q -- so they *can* excite one another), they will ring incoherently. This causes the mode amplitude to be proportional to N.
Thus, the amplitude of the incoherent ringing will be lower by a factor of N.
On top of this, they also add absorbing material to take out some of the power (the damping you refer to), and it is this that fits your guitar string analogy, not the detuning that Roger was referring to in the article. Absorbing material cannot change the frequency of the oscillation -- all it can do is remove energy from it, thus damping it's amplitude.
To go further, yes the differing stiffnesses of the springs under my car *does* look like a system of bells ringing at different frequencies. They are each ringing at a different "pitch" in order to detune any destructive vibrations. Your car analogy, including the absorbing rubber, is almost perfect!:)
I think the confusion is coming from the fact that this system can use both the absorbing material that fits your guitar string analogy, and the detuning technique that fit's Roger's bells. His analogy *does* describe the system very well, and I hope you can see that now.
The article's explanation is quite bad -- wakefields aren't really anything to do with twisting and warping "the very fabric of space-time". They're just the electromagnetic energy left behind by the beam as it traverses these cavities.
I think his bell analogy is actually quite good. He goes on to say that damped detuning is much more preferable to strong damping, and it is strong damping that is more like resting a finger on a guitar string. The problem he is trying to solve is that of the entire structure of many cells ringing strongly at a particular frequency. This ringing will add coherently, thus lasting long enough to disrupt the next electron/positron bunch.
His solution is to make each cell ring at a slightly different frequency, thus causing them to add incoherently, and strongly reducing the resultant amplitude.
Just like a collection of bells ringing with different notes.
The object's size subtends an angle from the point of view of an observer. This angle is (roughly) the size of the object divided by its distance from the observer.
It's a very useful way to discuss an object's apparent size in the sky, especially when you compare it to the size of a well known object like the Moon.
So, they're claiming that, if you could see this ring, it would appear to cover an area of sky roughly twice the size of the Moon. Which is surprisingly large.
Both. They vary the frequency over the light pulse so that different parts of the pulse travel with different speeds, thus causing the back of the pulse to catch up with the front.
Case 1: Cop plants real meth (not bicarb) in your car. You have to explain it (i.e. prove the cop committed a crime), or go to prison for a while.
Case 2: Cop plants data file filled with random data on your laptop. You have to explain it (i.e. prove the cop committed a crime, or prove it isn't an encrypted file (impossible)), or go to prison for a while.
In both cases the assertion of a crime is not enough (in case 1 he has to plant real meth in your car, in case 2 he has to plant a random file on your hdd), and in both cases the cop has to commit a crime (tampering with evidence, or whatever) in order to put you away.
I still don't understand what powers this new law gives to a corrupt cop that don't already exist.
If he didn't plant an encrpyted file, then the defence lawyer could demonstrate its lack of existence during the trial.
The corrupt cop would still have to commit a crime (planting of the encrypting file) in order to lock you up. Just as in the case of him "finding" a stash of meth in your car.
I don't understand what leverage this gives the corrupt cop that previous laws haven't already provided.
I don't care whether or not the people in these cases were being investigated for "really good reasons". The potential for abuse of this law is staggering. One cop says you have an encrypted file, which he may have planted himself - BANG. You are in jail. As fucking easy as that.
Sure, but isn't that the case already? Aren't there lots of other laws that can be abused in exactly the same way?
Perhaps the corrupt cop "found" a stash of meth in your car. Perhaps they "found" kiddie porn on your laptop. You're just as much in trouble as you would be if the "found" an encrypted file.
What abuse does this law allow that isn't already possible using other laws (and please don't flame me for going against the flow here) ?
The radiation that is emitted by the beam being bent around the synchrotron is actually called synchrotron radiation. Bremsstrahlung is a similar process where charged particles emit radiation when decelerated.
The physics is approximately the same (the acceleration -- transversely in the case of synchrotron radiation, and longitudinally in the case of bremstrahlung -- causes a reorganisation of the field lines of the particle), however they are given different names to distinguish their somewhat different properties.
A good example of both of these effects is the braking felt by particles when they interact with an opposing, oppositely charged beam at the interaction point of a collider. The field of the opposing beam causes the beams to pinch (focus transversely) and brake (decelerate longitudinally), thus yielding a huge radiation field called (rather unimaginatively) "beamstrahlung".
Have you ever double-blinded this experiment? I.e. get someone to offer you a glass of milk (making sure that they have no idea whether it is organic or not), and testing whether you can determine if it is regular or organic?
OK, I know this experiment has the risk of leaving you with bad cramps, etc., but I was just wondering if you had ever tried.
I think you're wrong. LCLS produces light by using the undulators to amplify the spontaneously emitted light from structure already present on the electron bunches. It does this in a way that is a precise analogue of a conventional laser, and the physics of the light production can be studied and discussed in exactly the same way.
And this is SLAC's first x ray laser, and the world's first x ray FEL. Please provide links if you feel I need corrected. Cheers!
The article you link to shows that FELIX is an infra-red FEL, not x ray. FLASH, the other FEL that people have been mentioning is VUV, not x ray.
So I still think that this is the first *beam based* x ray laser. A slight correction from my original title (due to the existence of the NOVA experiment), but FELIX is most definitely not an x ray laser.
Interesting point. In this case, perhaps the vendors could advertise on the fact that their batteries are guaranteed to output a certain number of Ampere.hours (at whatever voltage is is that these things run at)? They would then test and discard any substandard batteries.
Does anyone know if battery testing technology is sufficiently advanced for this to be feasible?
But I don't think that negates the importance of LCLS switching on. One example is that the Nova laser you linked to can only be fired 6 times a day, whereas LCLS should be able to run quite happily at 50 Hz, or more, for days (weeks?).
Slashdot Mirror
I think he expects to be tried & imprisoned when an IP linked to him is found accessing such sites, and he's saying that online vigilantism will probably appear to be quite a weak defence.
Replying to undo incorrect moderation...
I think the idea is that you need a mechanism whereby two objects close enough together to thermalize, are pushed far enough apart fast enough that they appear to be too far apart to have equalized.
I think.
Never mind. Mod my previous post redundant. If I'd read further in the thread, I would have seen that this had already been pointed out.
http://en.wikipedia.org/wiki/Planck_length#Physical_significance
I don't think you're right. It's just a distance unit formed out of c, h, etc., and is not the granularity of space.
It's only real significance is that, at this length scale, physics will (in some theories) be dominated by quantum effects.
Posting to get rid of unintentional "funny" moderation.
Set up a Facebook group to fight against the continued xmas dominance of Simon Cowell's evolved algorithms.
That's not quite true.
Experimental accelerator physicists (not particle physicists) will come up with a conceptual design for the machine that fits the particle physicists requirements, and they will then work with engineers to design and build it.
Most of the designing and building is done by properly qualified engineers, not scientists.
Hadron collisions were achieved last week in all four detectors.
But leave my goddamn radio at my desk alone.
If anyone else can hear that radio, I hope you've counted the number of "employee units" within earshot, and the number of half hour increments during which you play the radio, and paid the appropriate tariff.
http://www.prsformusic.com/SiteCollectionDocuments/PPS%20Tariffs/I-2009-03%20Tariff.pdf
*shakes head sadly*
I wish I was making this up.
FYI -- I work on this project, and I work with Roger Jones (the guy in the article), so I know a substantial amount about this.
Your definition of damping is quite right, but your definition of detuning is, in this case, not really what he means. What he means is taking a cavity, and changing its shape in order to "detune" some cells.
To explain:
The cavities are traditionally built in such a way that each cell rings (like a bell) at the design frequency of the accelerating rf. Since all of the cells are identical, the beam will excite exactly the same mode frequencies in each one (like a hammer hitting a bell). Since they are resonant with each other, they can and will ring coherently. Thus the amplitude of these modes will be proportional to N^2 (where N is the number of cells).
If they are made to have slight differences (detuned) that cause their resonant frequencies to be slightly different (but still within the bandwidth of each other due to their finite Q -- so they *can* excite one another), they will ring incoherently. This causes the mode amplitude to be proportional to N.
Thus, the amplitude of the incoherent ringing will be lower by a factor of N.
On top of this, they also add absorbing material to take out some of the power (the damping you refer to), and it is this that fits your guitar string analogy, not the detuning that Roger was referring to in the article. Absorbing material cannot change the frequency of the oscillation -- all it can do is remove energy from it, thus damping it's amplitude.
To go further, yes the differing stiffnesses of the springs under my car *does* look like a system of bells ringing at different frequencies. They are each ringing at a different "pitch" in order to detune any destructive vibrations. Your car analogy, including the absorbing rubber, is almost perfect! :)
I think the confusion is coming from the fact that this system can use both the absorbing material that fits your guitar string analogy, and the detuning technique that fit's Roger's bells. His analogy *does* describe the system very well, and I hope you can see that now.
The article's explanation is quite bad -- wakefields aren't really anything to do with twisting and warping "the very fabric of space-time". They're just the electromagnetic energy left behind by the beam as it traverses these cavities.
I think his bell analogy is actually quite good. He goes on to say that damped detuning is much more preferable to strong damping, and it is strong damping that is more like resting a finger on a guitar string. The problem he is trying to solve is that of the entire structure of many cells ringing strongly at a particular frequency. This ringing will add coherently, thus lasting long enough to disrupt the next electron/positron bunch.
His solution is to make each cell ring at a slightly different frequency, thus causing them to add incoherently, and strongly reducing the resultant amplitude.
Just like a collection of bells ringing with different notes.
I think you're wrong.
The object's size subtends an angle from the point of view of an observer. This angle is (roughly) the size of the object divided by its distance from the observer.
It's a very useful way to discuss an object's apparent size in the sky, especially when you compare it to the size of a well known object like the Moon.
So, they're claiming that, if you could see this ring, it would appear to cover an area of sky roughly twice the size of the Moon. Which is surprisingly large.
Both. They vary the frequency over the light pulse so that different parts of the pulse travel with different speeds, thus causing the back of the pulse to catch up with the front.
I think you misunderstood me.
Case 1: Cop plants real meth (not bicarb) in your car. You have to explain it (i.e. prove the cop committed a crime), or go to prison for a while.
Case 2: Cop plants data file filled with random data on your laptop. You have to explain it (i.e. prove the cop committed a crime, or prove it isn't an encrypted file (impossible)), or go to prison for a while.
In both cases the assertion of a crime is not enough (in case 1 he has to plant real meth in your car, in case 2 he has to plant a random file on your hdd), and in both cases the cop has to commit a crime (tampering with evidence, or whatever) in order to put you away.
I still don't understand what powers this new law gives to a corrupt cop that don't already exist.
I don't understand that.
If he didn't plant an encrpyted file, then the defence lawyer could demonstrate its lack of existence during the trial.
The corrupt cop would still have to commit a crime (planting of the encrypting file) in order to lock you up. Just as in the case of him "finding" a stash of meth in your car.
I don't understand what leverage this gives the corrupt cop that previous laws haven't already provided.
(Thank you for not flaming ;) )
I don't care whether or not the people in these cases were being investigated for "really good reasons". The potential for abuse of this law is staggering. One cop says you have an encrypted file, which he may have planted himself - BANG. You are in jail. As fucking easy as that.
Sure, but isn't that the case already? Aren't there lots of other laws that can be abused in exactly the same way?
Perhaps the corrupt cop "found" a stash of meth in your car. Perhaps they "found" kiddie porn on your laptop. You're just as much in trouble as you would be if the "found" an encrypted file.
What abuse does this law allow that isn't already possible using other laws (and please don't flame me for going against the flow here) ?
Not quite.
The radiation that is emitted by the beam being bent around the synchrotron is actually called synchrotron radiation. Bremsstrahlung is a similar process where charged particles emit radiation when decelerated.
The physics is approximately the same (the acceleration -- transversely in the case of synchrotron radiation, and longitudinally in the case of bremstrahlung -- causes a reorganisation of the field lines of the particle), however they are given different names to distinguish their somewhat different properties.
A good example of both of these effects is the braking felt by particles when they interact with an opposing, oppositely charged beam at the interaction point of a collider. The field of the opposing beam causes the beams to pinch (focus transversely) and brake (decelerate longitudinally), thus yielding a huge radiation field called (rather unimaginatively) "beamstrahlung".
Not flaming. Just wondering.
Have you ever double-blinded this experiment? I.e. get someone to offer you a glass of milk (making sure that they have no idea whether it is organic or not), and testing whether you can determine if it is regular or organic?
OK, I know this experiment has the risk of leaving you with bad cramps, etc., but I was just wondering if you had ever tried.
I think you're wrong. LCLS produces light by using the undulators to amplify the spontaneously emitted light from structure already present on the electron bunches. It does this in a way that is a precise analogue of a conventional laser, and the physics of the light production can be studied and discussed in exactly the same way.
And this is SLAC's first x ray laser, and the world's first x ray FEL. Please provide links if you feel I need corrected. Cheers!
Really, as far as I know LCLS is the first x ray FEL. FLASH is not an x ray FEL (it's VUV), and neither is FELIX (it's infra-red).
Can you link to the machine you're talking about?
The article you link to shows that FELIX is an infra-red FEL, not x ray. FLASH, the other FEL that people have been mentioning is VUV, not x ray.
So I still think that this is the first *beam based* x ray laser. A slight correction from my original title (due to the existence of the NOVA experiment), but FELIX is most definitely not an x ray laser.
Interesting point. In this case, perhaps the vendors could advertise on the fact that their batteries are guaranteed to output a certain number of Ampere.hours (at whatever voltage is is that these things run at)? They would then test and discard any substandard batteries.
Does anyone know if battery testing technology is sufficiently advanced for this to be feasible?
FLASH is (I thought) VUV, not x ray, and the Euro XFEL hasn't turned on yet, so I still think that LCLS is the first x ray FEL.
Thanks for those links. I stand corrected :)
But I don't think that negates the importance of LCLS switching on. One example is that the Nova laser you linked to can only be fired 6 times a day, whereas LCLS should be able to run quite happily at 50 Hz, or more, for days (weeks?).