Scanning Tank

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General instructions for the scanning tank</center>

Water in and water out

  1. Filling the tank
    1. Fill tank with water from pipe connected to sink
    2. Put both ends of UV pump in (thing that looks like a small bin with hoses connected). Making sure the pipes are in place (they do move when the power is switched on). Plug both the pump and the filter in (two white sockets into four way). This prevents the water from becoming too skanky and discouraged algae growth.
  1. Emptying the tank - if you are leaving it for a week or more
    1. Unplug pump, remove return hose from tank and put into sink
    2. Plug in pump. This should start emptying tank into sink (again watchfor pipes moving with pressure best to hold onto return hose)
    3. When the water level is too low for the pump unplug both the UV filter and the pump.
    4. Break out the dust pan and remove the last couple of inches (it doesn'ttake too long) being careful not to soak the controller. A bit of paper towel can be used for the last bits the dustpan can't get.

Mounting samples / transducers etc

You'll need to improvise a lot to mount your sample / transducers etc and, in some cases, this means making a new mount to hold things. Bear in mind when you put stuff in the tank that some things float! Also try to keep things simple and watch out for collisions.

Try to remember which cable is which - it has been known for experiments to give strange results and for this to be tracked down to the wrong transducer being plugged in!

Controlling things from the computer

The tank is controlled from the host hammock please do not update any software on this computer without consulting Matt or Steve first - there are a lot of complex dependencies for the driver software.

First log into hammock (PC by the tank) as usual.

The main scanning functions are performed using c_scan as usual - however the way the driver software works means that there is a back end (deamon) that takes care of the hardware for c_scan (and manual_tank). This needs to be running before anything else (see instructions for tank_server). If you get odd errors this deamon might not be running.

c_scan on hammock is compiled with the tank options - try man c_scan to find the instructions!

manual_tank is used to line up the arms, set the origin etc etc and is the equivalent to manual_stage used elsewhere.

Put your data in the proper place

Proper place for experimental data

How to scan

Handy examples in "/home/scan/2012/july/tank/testscansample" this includes a handy matlab script which can write .con files for c_scan to use.

  1. Turn the pulser on (flick switch labelled pwr) and turn the Polytech laser on (laser button on laser unit) you will see a red spot on your sample. This is a class 2 laser meaning it is blink safe. In other words so long as you don't sit there looking at it for long periods of time forcing yourself not to blink you should not cause any damage to yourself.
  1. This program lets you control the position of the stages using the keyboard arrows, pressing the “f” makes the step sizes bigger and pressing the “s” key makes it go slower. Before moving the stages make sure the emergency stop button is deactivated (rotate it clockwise till it pops up). If at any point you think the stages are going to crash into something press the emergency stop button and go find steve. Move the stages round to line up the sample, the interferometer spot and the transducer. Hopefully with a few averages on the scope (16-256 kind of range) you should be able to see the UT pulse. Get all the bits aligned and press the “o” key to set the origin. You should set it for all axis, hence press the “a” afterwards. Make sure you note the numbers. If at any time you need help press the “h” key.
  2. Using a file browser (goto the “start menu” and select the home icon) navigate to where you have made your sample folder (/home/scan/2012/july/tank/NAMEOFSAMPLE). Edit the generate_psf_movie_confiles using a text editor (right click, open with, kwrite). Make sure the numbers that each axis is going to move makes sense (all numbers are in microns, its historical) with those noted when using manual_tank. You may also want to change the filename variable. NOTE: the distpsfover variable defines the length of the line the different psfs will be taken over, the axis5stepsize indicatest the size of each step between psfs. The set_origin function resets the orgin by the step size each time round so a slightly different part of the sample has a psf run on it each time. This code has only been dry tested (not collecting UT signals) and so may require further work. Save any changes
  3. In console 1 type: “matlab_java &” (this will bring up a matlab window).
  4. In console 2 quit manual_tank by pressing the “q” button. You should not need to move the stages back to 000 so press “N”
  5. So long as your happy in the matlab window type:
  6. The stages should start moving about and the scope should start collecting data. Again if anything looks like its about to crash press the emerency stop. If you figure out your in the wrong place or something pressing “ctrl+c” will stop the process.
  7. Once the data collection has finished edit plot_psf in kwrite so the base_name variable matches the name of your data files. You can then run this in matlab, Hopefully it will generate all the pictures you need. These can be put into a video. I will refer you to steve.
  8. To put in a new sample move the sample arm up in manual stage.
  9. On completion of the data collection, switch off pulser, polytech (laser button, followed by key switch) and then scope.
  10. Close all windows and log out of pc.
  11. Press the emergency stop button.
  1. Good luck!

Scanning Tank PSF scans

The pulser is over with Xeusheng, there are two coax cables to the left of the monitor that need pluging in (both are labelled with postit notes about which ports they need to go into). Plus there is a power cable. It should just be plug and play.