I started with a ship full of max-level veterans, and I'm just a complete noob.

After Director Wang's phone call in the early hours of the morning, Jiang Ming only slept for less than three hours.

Before dawn, he returned to the secure compartment, took the anode blanks that had been sealed away the day before from the safe, peeled off the wax paper, and the copper surface gleamed a deep red under the incandescent light.

At nine o'clock in the morning, when Fang Xudong pushed open the door and came in, Jiang Ming had already posted a hand-drawn assembly flowchart on the wall.

Fang Xudong stood in front of the diagram for a while, his finger hovering over the cathode column.

"What cathode do you plan to use?"

"Cerium oxide".

Fang Xudong turned around and raised an eyebrow.

"The original Soviet version used a barium-calcium-strontium oxide cathode, aren't you going to follow suit?"

Jiang Ming took the cathode fragments of the seized magnetron from the iron box and placed them in front of Fang Xudong.

The surface of the fragment is covered with a layer of grayish-black powder, which falls off with a gentle touch of tweezers, revealing the corroded and pitted nickel substrate underneath.

"Barium-calcium-strontium cathodes are susceptible to poisoning. Water vapor, carbon dioxide, oil vapor, or any other harmful gas can cause the emission current to decay to the point of being unusable within a few hundred hours."

Jiang Ming turned the wrecked piece over and pointed to a ring of black scabs at the bottom.

"The cathode of this captured tube is severely poisoned, and its firing efficiency is estimated to be less than 30% of the original, indicating that its lifespan under field working conditions is very short, probably only one or two thousand hours."

Fang Xudong did not immediately refute. He took the fragment, examined it for a while, and then put it back into the iron box.

"Cerium oxide has a lower emission density than barium, calcium, and strontium."

"About 20 percent lower."

Jiang Ming nodded in acknowledgment of the defect.

"But the cathode of the type B tube in Workshop No. 1 has been running for more than 500 hours, and the emission current has decreased by less than 3%, which is far better than the barium-calcium-strontium route in terms of resistance to poisoning."

He circled the cathode parameter column on the drawing with a red pencil.

"The operating temperature of the magnetron cathode is 200 degrees Celsius higher than that of the B-type tube. I increased the thickness of the electrophoretic coating from 40 micrometers to 60 micrometers for the B-type tube to ensure sufficient emission reserves at high temperatures."

Fang Xudong was silent for a moment, then tapped his fingers lightly twice on the table.

"In other words, the tubes we produce have a frequency comparable to the Soviet-made ones, but their cathode lifespan may surpass that of the original."

"The premise is that there are no assembly problems."

Old Sun came in through the side door at this moment, his work clothes sleeves rolled up to his elbows, carrying a tin toolbox in his hand.

"I had Da Liu prepare the electrophoresis tank last night. The concentration of the cerium oxide suspension was based on the formula for the type B tube. It was stirred all night, and the dispersion was qualified when measured this morning."

Jiang Ming nodded to him.

"Where's the cathode sleeve?"

"The nickel cylinder was machined yesterday. It has an inner diameter of 7 millimeters and a wall thickness of 0.3 millimeters. The surface has been polished with 100-grit sandpaper and degreased twice."

Da Liu carried in an electrophoresis tank from next door. The glass container, about the size of an enamel basin, contained a pale yellow suspension. The surface of the liquid swayed slightly, and it looked like diluted egg yolk water.

The electrophoresis process itself is not complicated. Jiang Ming had already mastered the process three months ago when he was working on the B-type tube.

With the nickel cylinder as the anode and the copper sheet as the cathode, and the DC voltage adjusted to 80 volts, the negatively charged cerium oxide colloidal particles in the suspension will be uniformly deposited onto the outer surface of the nickel cylinder under the drive of the electric field.

Da Liu secured the nickel cylinder with a stainless steel clamp, slowly immersed it into the bath, then connected the wires and turned on the regulated power supply.

The ammeter pointer jumped from zero to fifteen milliamps, and then stabilized.

Jiang Ming glanced at the hanging clock.

"Timer begins, twelve minutes of sedimentation."

No one spoke for twelve minutes; the only sounds were the hum of the power fan and the occasional soft tapping of the stirring rod against the glass.

Da Liu stared at the ammeter, jotting down a number in his notebook every two minutes.

When the time was up, Da Liu turned off the power and slowly lifted the nickel cylinder out of the bath.

The cylinder wall is covered with a uniform, light yellow coating that is moist, delicate, without any drips or particle accumulation.

Jiang Ming used a thickness gauge to take one point on each of the top, bottom, left, and right sides of the cylinder wall. The readings were 58, 61, 59, and 62 micrometers, respectively, with an average of 60 micrometers. The deviation was within the allowable range.

"The cathode has passed."

He signed the record sheet, put the nickel cylinder into the drying oven, set the temperature to 120 degrees Celsius, and dried it for 40 minutes.

Now comes the real challenge of today.

Old Sun had been standing in front of the glass dustproof box for a while. Inside the box, a white dust-free cloth was laid out, and the anode copper block and the transition Kovar alloy sleeve were placed side by side.

Kovar is an iron-nickel-cobalt alloy with a coefficient of thermal expansion close to that of glass. The anode copper block of the magnetron must pass through this transition alloy to achieve a reliable vacuum seal with the glass shell.

The problem is that the welding temperature window for copper and Kovar alloys is very narrow.

If the temperature is too low, the solder will not be wetted sufficiently, leaving gaps in the weld and eventually causing vacuum leakage.

At high temperatures, copper grains grow abnormally, reducing mechanical strength. Furthermore, cobalt in Kovar alloys diffuses towards the copper side, contaminating the anode surface.

Old Sun pulled out a roll of silver-copper solder wire from the bottom of his toolbox. It was 0.5 millimeters in diameter, contained 72% silver and 28% copper, and was the last batch of high-purity material he had applied for from the material warehouse three months ago.

He cut the welding wire into twelve equal-length loops, and bent each loop with tweezers into a shape that could just fit into the joint between the copper block and the Kovar sleeve.

"Jiang, I tested the hand-cranked vacuum welding furnace yesterday. It can be pumped up to 10 to the power of negative cube without any problem, and the heating wire can reach a maximum temperature of 850 degrees Celsius."

Jiang Ming walked to the dustproof box and looked down at the twelve silver-copper welding wire rings.

"780 degrees, keep warm for five minutes, do not exceed 800 degrees."

Old Sun nodded.

"I know, if the copper grains exceed the limit, it's ruined."

He aligned the anode copper block and the Kovar sleeve, inserted the welding wire rings one by one into the joint, and then installed the whole assembly into the quartz tube of the hand-cranked vacuum welding furnace.

The furnace wasn't big; it was modified by Old Sun himself from scrapped equipment. The outer shell was a section of thick-walled stainless steel cylinder, lined with a quartz tube. A mechanical pump was connected to the bottom, and there was an observation window and thermocouple leads on the top.

The term "hand-cranked" refers to a sealed rotating injection rod that allows the workpiece to be transferred from a cold zone to a hot zone without disrupting the vacuum.

The mechanical pump started pumping air, and the vacuum gauge pointer slowly dropped, stabilizing at 8 x 10 -4 Torr after five minutes.

Old Sun slowly increased the heating current, and the thermocouple reading climbed higher and higher.

Three hundred degrees, four hundred degrees, five hundred degrees, six hundred degrees.

At 650 degrees, a very faint glow begins to appear on the inner wall of the quartz tube. This is a trace of the ionization of residual gas molecules, indicating that a small amount of gas is still being released from the surface of the workpiece.

Old Sun paused for a moment, waiting for the vacuum gauge to stabilize again before continuing to apply the current.

700 degrees, 730 degrees, 760 degrees.

Jiang Ming stared at the thermocouple readings, holding a recording pen in his hand, the pen tip hovering above the paper, not falling.

780 degrees.

Old Sun stopped heating and kept the current constant.

"Timer."

During the five-minute heat preservation period, nothing could be seen in the observation window of the quartz tube except for the dark red light emitted by the heating wire, which illuminated the entire tube cavity as a uniform dark color.

The vacuum gauge reading stopped fluctuating and remained steadily at 7 x 10 -4.

Five minutes later, Lao Sun disconnected the heating current and then slowly pulled the workpiece from the hot zone back to the cold zone using a hand crank.

Cooling is the most patience-testing part; you can't open the furnace or let the gas in, you can only wait.

An hour and a half later, when the thermocouple reading dropped below fifty degrees, Lao Sun turned off the pump, broke the vacuum, and opened the furnace door.

He used long tweezers to pick out the soldered components and placed them on a clean cloth.

The weld appears silvery-white under the light, is smooth and continuous, and has no porosity or overflow.

Jiang Ming aimed the probe of the helium mass spectrometer leak detector at the outside of the weld, and connected the other end to the inner cavity of the component.

After the leak detector had been preheating for ten minutes and the background noise had stabilized, he turned on the helium spray gun and slowly swept it along the weld.

The pointer on the leakage rate indicator remained completely still.

He scanned it a second time, then a third time, from a different angle, from top to bottom, and from left to right.

The pointer remained near zero, and the final reading was less than ten to the power of negative ten per second.

"Weld seam grid".

Jiang Ming wrote down the data on the test report, signed his name and the date.

Old Sun put the tweezers back into the toolbox, his fingers trembling slightly. It wasn't from nervousness, but from not having eaten anything all morning, which made his blood sugar a little low.

Fang Xudong had been standing silently to the side until now, when he walked to the workbench and looked down at the component with its distinct copper and silver color.

The anode is made of domestically produced oxygen-free copper, the cathode coating is cerium oxide electrophoretic deposition, and the transition seal is Kovar alloy silver-copper vacuum welding.

Nothing was copied directly from the original Soviet version.

He stared at it for a long time, his voice very soft, as if he were talking to himself.

"This may be a microwave structure invented by the Chinese themselves."

No one responded to that sentence.

Jiang Ming was already preparing for the next step. He carefully installed the assembled magnetron body onto the glass tube seat of the vacuum exhaust station and tightened the flange with a rubber sealing ring.

The exhaust station is an old piece of equipment in Workshop No. 1. It was used for high-temperature exhaust of the B-type pipe three months ago, and now it has to take on an even heavier task.

He checked all the pipe connections and confirmed that the diffusion pump oil level was normal, the cooling water valve was open, and the mechanical pump belt was tensioned.

Once everything was ready, Jiang Ming placed his hand on the handle of the exhaust valve.

The valve was slowly opened, and the roar of the diffusion pump and the mechanical pump started almost simultaneously, causing the iron frame under the exhaust platform to tremble slightly.

The vacuum gauge pointer began to drop, falling all the way down from atmospheric pressure.

The exhaust process of the magnetron has officially begun.