restindex page-title: little-ICELog crumb: little-ICELog link-title: little-ICELog page-description: Photo blog of the experiment I work on. /description /restindex ============================================ Photo Blog of the Little-ICE Experiment ============================================ .. .. warning:: **Personal Opinion Disclaimer** This page reflects only my personnal views and opinion, and not the views of my employer. *Little-ICE* is a side project that I am running for a few month. It is a small version of the main experiment that is going to fly in the `Zero-G airbus `_ with the lasers from ONERA. The whole project is 4 months long, to build a test-flight compatible experiment ! So progress should go quickly :->. Oh, before you ask, flight is last week of March. **ICElog**: | `latest news <./index.html>`_ | `all 2007 <./2007.html>`_ | `all 2006 <./2006.html>`_ | 29/03/07 -------- .. raw:: html

28/03/07 -------- And the second flight today. .. On a scientific point of view it wasn't too much of a success. The MOT fiber amplifier is most probably dying and we pretty much lost an order of magnitude on the power coming out of the MOT fiber. But that was enough to get a decent MOT by raising the loading time from 1s to 2s. We had difficulties with the sequencer. It was really doing completely unexplicable things. The sequences seemed pretty much random on different channels and after some time the sequencer added a lot of noise on its outputs. I tried many things, tweaked the sequences, undid the changes I had done, all this during the one minute break between parabolas. I also moved channels around on the sequencer, managing to lose a connector (we didn't see it fly by but it is quite clearly missing in action). All I did managed only to get things worse. After a while it was clear that I wasn't improving things, so I started releasing my straps and floating next to the computer. I went to play in the free flight zone, did a few looping and some mid air swiming (Philippe tells me that on the movies I am swiming forward, and actually going backwards), went back in the cockpit for a parabola (That's a pretty crazy experience, you know, and quite a daunting one). This afternoon Arnaud and I worked on trying to find out what was wrong with the sequencer. Most of the time when I have difficulties with the sequencer it is due to a bug in the software but today it looked more like a hardware problem. Well after shorttening a few lines to avoid oscillations and adding a layer of fans on top of it, it is doing fine ! Maybe it was just that the poor thing was overheating in microgravity, as it is only cooled by free convection. So tomorrow we will try to use the Raman sequence that I quickly coded this afternoon to see some transfert. .. raw:: html

27/03/07 -------- Today was the first flight. I wont give to much news as we are all very tired and we need to go to sleep early. Philippe, Nassim and I flew. All went very well. The MOT was just fine. Nassim was sick and Philippe was slightly sick. We are all very tired. I need to sleep more. It was an increadible experiment. I will write more on that. We have a lot of work to keep on moving and get more results. .. raw:: html

26/03/07 -------- Today was the last day before the flight. The sequencer gave us many troubles and we gave up on running it in autonomous mode. The power at the output of the fiber is fluctuating in a very strange way. We had the briefing, security check... Everything went well, we just had to tape down a few things. .. raw:: html

23/03/07 -------- Philippe joined us and Nassim and him worked on synchronizing the Raman lasers. I work a bit more on the sequences, to allow us to hand-scan a few parameters (including time of flight), and started looking at how to acquire data from the scopes. .. raw:: html

22/03/07 -------- This moring the experiment was at 5 degrees celcius ! Power in the lasers was terribly low and we had to ask for the plane's heater to be turned on. So please close the door ! Once the plane reached a decent temperature the lasers worked just well and we had a MOT quite quickly. Our first MOT in the plane ! We worked a bit on the sequences and on the compensation coils. In the afternoon we had nice signal on the photodiode. We tried plugging it in the computer controled acquisition card, only to find out that the card was killing our signal. Indeed our signal was very low (60mV amplitude), but it wasn't noisy at all. The card add loads of noise at 100kHz. We called the SYRTE and they are working on a solution (either an amplifier for the photodiode, or an other photodiode. If this fails we will acquire the signal from the scopes. .. raw:: html

21/03/07 -------- Today we loaded the experiment in the plane. We positioned it and started connecting the different racks and testing the equipment. Things had not moved as much as we had thought they would have (the truck that carried the experiment vibrated as hell), but a fiber had been badly damaged. Surprisingly it is still working. We had a big fright because the hyperfrequency source would turn on. It turned out it was only a switch that had been mounted the wrong way around. Fixing this was just a matter of changing the labels. .. raw:: html

20/03/07 -------- Today Nassim had some problems on the road, and he arrived too late for us to load the experiment in the plane, so we tweaked little bit the setup. We had to make sure every single little bit of aluminium was properly grounded. Of course a few where not... .. raw:: html

19/03/07 -------- I arrived at Novespace an hour before the experiment. When the ONERA truck arrived we immediately unloaded the racks. It was pissing with raining. Thankfully the driver had backed out all the way to the tent and there was only one meter of shower to cross. Unfortunately that meter was the one where we had to maneuver the racks. Now they are in the tent, and all is well. .. raw:: html

16/03/07 -------- This morning I drove straight to the electrical shop I bought the new UPS. It is a 3U rack, and the current one is a 2U rack, so we will have to rearrange completely the rack number 3. And it is not just a question of moving things up, as the rack is currently completely full. Nassim came around today and with him we move a 1U unit to the side of rack number 3 and re built rack number 3. The experiment is now in its final state. Tomorrow we pack it and load it into the truck for Bordeaux. I am looking forward to a nice restful week end. .. raw:: html