BW February 2018

2/1: Dr. Jones said we do need a light guide bundle highly polished on both ends for calibrating the fiber testing equipment. I chose bundle 406 with the black strap and got it on the polishing plate yesterday, but it was not yet aligned. This morning I aligned it as well as I think it will be. I think it needs just a little polishing with 1000 grit to get all the fibers to be exactly in one plane. Since the fibers on the left side are sticking out a tiny bit less than the rest, I want to twist right in front and left at the rear of the polishing plate.

2/2: I finished polishing bundle 406 upstream so we have a bundle highly polished on both ends.

I also reviewed the fiber testing equipment so I will be ready to discuss it next week. That way I can show what I know and learn what I need to.

2/5: I did some fusing practice, and the strongest fuse that I measured held 1200 g plus the hanger. It broke under 1300 g and the hanger. Dr. Jones said wings are unavoidable, and I should remove them with a razor blade, not sandpaper.

2/8: Jim said I should keep a separate logbook for fiber testing. I should include links to the histograms of run results and also to the text files (maybe on Gluey?) that can be opened with a spreadsheet. Once I test fibers, they should remain in the same bundle position for all subsequent tests. I should note anything unusual, such as fibers that need to be sanded to go in the chimney or fuses that break.

I told Jim about the leak in the splicing unit that Ann Marie mentioned to me. He found that it was coming from a hose connection. He tried to fix it, but the connector broke and we will need to order a new one.

I did six or seven test runs this morning with the dark box. After run 1359, they stopped completing. Jim looked at the cron.log and said things were hanging there. My test runs would not complete if I used the commands in the browser. He also said the relative pulse normalization should not be zero. I had not noticed that it was zero. The results looked fairly good otherwise. The only unusual feature I noticed was an isolated spike sometimes appearing near the highest part of the plot. It reminded me of a TV or radio antenna on the slope or at the top of a hill.

2/9: I asked Jim to get me started on fiber testing. He can do that tomorrow. I also requested 0.188" washers for aligning sci-fis. I would like to find the knife for removing extra material and burs from the printed parts.

Jim showed me that the scraper knives are in a desk drawer in room 403. I removed some excess material from the sci-fi collar that was on the desk in 403.

Then I put 400 grit paper on the polishing wheel to get ready for polishing sci-fis.

2/13: I removed excess material from the sci-fi collars and washers Jim printed for me yesterday. Then I realized the holes in the washers were too small for the screws. Jim said the washers should not be tapped, but the holes can be enlarged with the round file. I tried doing that, but I did not get the hole bigger with the round file.

I swept in lab 405 and cleaned around the 3-D printer. I also requested a pick-up for two boxes of used batteries and the contents of the sharps container. I found a page on the UConn website about Responsible Conduct of Research training.

2/15: Jim showed me how to drill the holes in the sci-fi collars using the drill press. He explained the major and minor diameters of a screw. The major diameter includes the threads but the minor diameter is the narrowest one at the deepest point of the grooves between threads. We can measure the major diameter easily with a micrometer, but the number of threads per inch is harder to tell.

A screw number such as 4-40 means that the screw size is 4 and there are 40 threads per inch. When drilling holes to be tapped, they should be a little larger than the minor diameter and less than the major diameter. The tap hole needs to be larger in harder materials such as steel or iron than in softer materials such as brass or aluminum.

Clearance holes are larger than the major diameter and they can be either a close fit or a larger free fit. For the washers we used the free fit.

The screws for the sci-fi guide are 6-32.

Another useful tip is that there is a little knob for locking the micrometer.

When drilling I had to go slowly and back the drill bit out as needed. I am still not really sure when to back it out, but I did it for every washer I drilled. My best drill holes seemed to be in the last two washers. They did not have much material projecting after I was done.

Here is the drill user manual.

2/16: Yesterday I started polishing a bundle of sci-fis that are cut to 0.907 inches. The screw holding the collar on the guide was on the left. With the micrometer I measured the space where we put the feeler gauges. It was about 0.09". I wanted to try bottoming out to the 0.025" feeler gauge. I twisted right in front at the polishing wheel and left in back away from the wheel.

2/19: Using the Carson camera, I identified which fibers are in each position in the bundle to be tested. Jim will show me tomorrow how to use the alignment jig for testing. I continued polishing the sci-fi bundle after identifying the fibers.

2/20: Today I tried aligning the fibers for testing as Jim explained. I have not succeeded with that yet. I also continued polishing the same bundle of sci-fis.

2/21: I aligned the fibers in bundle 401 or 402 for testing (there is a contradiction between the ID collar and the strap color). There is one more problem, though. The fibers still seem prone to slide out of the Kapton straps. They might not stay in the right position on the popsicle stick as they are put in the dark box.

2/22: I put the fibers on the popsicle stick again. Yesterday I had them aligned but when I put them in the dark box they were bent differently and no longer aligned. I held up a measuring tape in the dark box and decided the horizontal distance between the popsicle stick end of the bundle and the top of the ramp is about 26 inches. Then I used a box on the conference room table to substitute for the top of the ramp and put the fibers in a position similar to what they assume in the dark box. I also had a stack of journals to hold the chimney end of the bundle in the bent position as it is in the dark box.

After some failed attempts, I aligned the fibers about right by holding them on the table in approximately the dark box position. Then I used the plexiglass stop plate to align them, but they were still not in the right position when I put them on the popsicle stick. I finished the alignment by pushing the fibers against the alignment jig while holding the slender part of the jig so it wouldn't break.

I put the fibers in the dark box and put them in the chimneys, but I may have bumped the laser while doing that, so the dark box might not work anymore. Somehow the curtain had fallen and I was trying to put the fibers in place with the curtain down. I had trouble finding the hole for the threaded rod on the popsicle stick too. From now on I will have to make sure the curtain is up before carrying the fibers to the dark box. I did raise it before taking the fibers out to bring them to the conference room. It must have fallen while I was working there.

2/23: I tried to run a fiber test, but the charts came up blank.

I continued polishing the sci-fis. I have some problems with measuring with the feeler gauges. It seems that while polishing there is less space for a feeler gauge than when the wheel is at rest. For example, with the 0.025" feeler gauge in place, the fibers don't touch the paper as the wheel is spinning. It's the same with the 0.024" gauge, but with 0.022" and 0.020", there is a little contact.

I was about to contrast this with the wheel at rest, but now I'm not so sure. I just found that at rest the 0.025" and 0.024" feeler gauges didn't fall down as I had seen earlier, but I had to press hard to keep them up. I will have to think some more about this.

But I think I will turn the sci-fis around again since it seems they are projecting more on the other side. This time the screw will be on the left.

Jim put the new part in the splicing unit and said I should check the pressures before fusing. I raised the pressure coming from the compressor and looked at the two regulators. I adjusted the right one that should be 95 PSI, but I could hardly turn the knob to adjust the left one that should be 57 PSI.

Before leaving, I drained the compressor at the bottom. There was not much rust this time.

I should have a to-do list for next week.

1. I need to know whether I am testing bundle 401 or 402.

2. I need to know whether I am reading the color codes the right way or backwards. I need to know if I am putting them in the chimneys correctly.

3. I need to interpret test results.

4. I need to address the problem with adjusting the pressure in the splicing unit.

2/26: Jim said the test data is being cut off at 675. I should remind Dr. Jones about that before I leave.

The fiber color code is read from the elastic farthest from the code end to the one closest to the code end. By code end I mean the end of the fiber that is closest to the color code.

As I thought, the SiPMs and chimneys closest to the backplane are numbers 1 and 16, and those farthest from the backplane and closest to the door are numbers 15 and 30.

Then bundle I have been testing is number 401, not 402, since the fiber color codes match the ones for bundle 401 given in the Summer 2017 Fiber Data Log. The data log shows yellow as the strap color on the Bundle 401 sheet and pink as the strap color on the Bundle 402 sheet. The Information sheet had the wrong colors for bundles 401 and 402, so I changed them.

I continued polishing the sci-fi bundle. Today I pressed harder and reached my goal with the 400 grit paper, which is to get 0.014" from the final length. I came close to the 0.025" feeler gauge on one end of the bundle and 0.029" with the feeler gauges on the other side.