Xueba starts with change

Chapter 214 Experimental Data (23)

At 10 o'clock in the morning, the experiment officially started.

The experiment will be carried out in three steps.

They are the short circuit test and open circuit test of the generator respectively, and the short circuit current and open circuit voltage will be measured.

A dummy load experiment from the generator to the transmission line to the dummy resistor will measure the voltage across the generator and the dummy resistor.

From the generator to the transmission line, and then to the beam output experiment of the diode joint test, the typical voltage and current of the diode will be measured.

The measurement of these data will be carried out by specific parameter measurement devices.

The experiment was carried out very quickly, and the data feedback was also timely.

With the switch closed, the last step of the beam-out experiment begins.

The fully charged magnetic pulse generator starts to discharge the diode through the double forming line to form a strong pulsed particle beam.

At this time, Chen Zhou also finally knew the diode used in this experiment, called the anode rod pinch focusing diode.

At this time, a coaxial diode was developed from the conical anode reflective target focusing structure used in early flash X-ray machines.

Anode rod pinch focusing diodes are constructed with a thin annular cathode surrounding a small diameter anode rod that tapers to extend a distance beyond the plane of the cathode.

In this diode, the electrons emitted by the radial cathode are pinched back under the action of the beam from the magnetic field, focused downstream of the cone, and finally bombard the anode tip made of heavy metal, thereby generating bremsstrahlung X-rays.

These X-rays are then emitted from the tip of the anode that is sharpened into a needle shape, creating a point source of X-rays.

The advantage of this kind of diode is that the focal spot formed is small, stable and simple in structure.

Chen Zhou estimated that this is also the reason why Dean Yang and the others chose the anode rod pinch focusing diode.

Then contact Peng Jia to finish what I just said, and there will be many other diode experiments in the future.

Chen Zhou carefully observed the feedback of various measurement data.

His greatest significance in this research group should be to discover the greatest value in these data.

Through the analysis of the data, the optimization of the experiment can be completed.

How to obtain a small focus, a strong current beam with stable shape and position, and how to obtain a large-area, well-uniform electron beam or ion beam, all need to be discovered from experimental data.

In particular, the research on strong pinch diodes, how to move towards high voltage > 10MV, small focus < 1mm, high brightness of 1R irradiation at 1000m, and multi-pulse and multi-amplitude directions are also included in the experimental data .

The experiment was soon over.

After finishing the experimental data, Dean Yang announced the end of the experiment and arranged preparations for the next experiment.

Chen Zhou was a little bit emotional, this experiment was really troublesome.

"Chen Zhou, how many days will it take to process the experimental data?" Dean Yang turned to look at Chen Zhou and asked aloud.

Chen Zhou hesitated for a moment, then said, "Two days."

Right now, he is not in a hurry to start the math project again, so he can spend all his time on this topic.

Hearing Chen Zhou's words, Lin Xiaoen and the others looked at each other, wondering if this kid hadn't processed the experimental data, it's been two days?

Originally, they were against Dean Yang's entrusting the task of processing data to an undergraduate, but Dean Yang gave Chen Zhou a guarantee.

It's hard for them to say anything more.

It's just that Chen Zhou's boasting made them a little worried.

However, Dean Yang said: "Okay, you can send the data results to me and Peng Jia respectively in two days."

Chen Zhou nodded.

Dean Yang arranged Yang Yiyi in the laboratory again, following Peng Jia.

Unlike Chen Zhou, Yang Yiyi is a pure physics student, and Dean Yang has higher expectations of her.

After briefly arranging the work of the laboratory, Dean Yang took Chen Zhou out of the laboratory.

After Chen Zhou left, Lin Xiaoen finally said: "Sister, do you think this kid is reliable?"

Naturally, Peng Jia knew that Lin Xiaoen was talking about Chen Zhou. She glanced at Lin Xiaoen and said, "Don't think about it. He is a student of the Department of Mathematics, and since Dean Yang values ​​him so much, there must be something special about him. .”

Lin Xiaoen still said: "But, this is an experiment that we have prepared so hard for so long, if it is delayed..."

"No." Yang Yiyi interrupted Lin Xiaoen, and said slowly, "If it's just data processing, I don't think anyone of us can compare to him. He is not just a student of the mathematics department."

Lin Xiaoen looked at Yang Yiyi suspiciously: "Do you know him well?"

Peng Jia also looked at Yang Yiyi with great interest.

Yang Yiyi smiled softly: "I understand quite well, he just recently solved the conjecture of hailstones."

"What? Hail conjecture?!" Lin Xiaoen and Peng Jia blurted out at the same time.

Although they have stayed in the laboratory for a long time, it does not mean that they do not know what the hail conjecture is.

"This, how is it possible? Isn't he just a sophomore?" Lin Xiaoen doubted that he had heard it wrong.

At this time, the researchers in the laboratory basically noticed the movement here.

The news that the little girl said was too shocking.

Yang Yiyi said indifferently: "Is going to sophomore year related to solving the hail conjecture?"

"Uh..." Lin Xiaoen was speechless.

But after get off work today, he will definitely check the news in this regard.

If it is true, then Chen Zhou will process the data, he has no opinion at all.

Just kidding, people who are professional in mathematics can't handle some experimental data?

Chen Zhou, who was already on the way back to Yanda, didn't know what happened in the laboratory.

Even if he knew, he probably wouldn't explain it.

When the experimental data is processed and the results are taken out, the doubts will naturally disappear.

In fact, Yang Yiyi didn't intend to talk too much at first, but this senior Lin Xiaoen, who looked enthusiastic, murmured her happiness behind her back, so what's the matter?
After returning to Yanda, Chen Zhou finished his lunch briefly, returned to the dormitory, and brought his computer to the library.

He said it would take two days, but according to his actual estimate, it would be about one and a half days.

"Pinching of the anode rod focuses the current development in the diode, got me thinking... umm..."

[At low voltage, the electrons move in the radial direction, which belongs to the space charge limited flow.At higher voltages, weak pinching begins and electrons begin to approach the anode, grazing incidence along the surface. 】

[At a higher voltage, a strong pinch occurs, forming a self-magnetic insulation flow. With the help of ions generated by the anode, electrons flow to the tip of the anode rod.Equipotential lines of electron flow are formed in the magnetically confined region, and most of the current reaches the tip of the anode rod. 】

After writing this process on the draft paper, Chen Zhou read it again, tapped the draft paper a few times habitually, and continued to write:
[In a non-cylindrical geometric mechanism, under the non-relativistic space charge limitation, the space charge limited current formula given by the Langmuir and Blodgett formula can be deduced that the diode current is inversely proportional to Ra when Rc/Ra is a constant , proportional to l...]

[That is, the critical current Ic=α·8.5·(γ0-1)^(1/2)/ln(Rc/Ra) for pinching, it has nothing to do with the length, it only depends on the radius of the cathode and the radius of the anode rod The value of the ratio Rc/Ra...]

【……当有离子时α增加，从Rc/Ra≈1~2时的α=1.6，增大到Rc/Ra=16时的α=3，γ0为相对论因子，且γ0=1+eV0/mec。】

【因此，在离开二极管距离1m处所产生的剂量可以用D(t)=7×10^(-4)I(t)V(t)^1.11rad.s^(-1)。】

According to the current development process in the anode rod pinch focusing diode, Chen Zhou first sorted out the formulas that need to be used.

For him, this is a comfortable way of data processing.

(End of this chapter)