Trials for the testing technology

Robert L. Flack

UCL

Test cell

• The cell has to have a full complement of wires.

• Need to be able to remove and replace all of the wires, hence also want spares.

• Require five ports for lenses.• Require holes next to each port to insert fibre

optic.• The length has to be four metres, or whatever

the agreed length is to be used in Supernemo.

Purpose and basis of the trials

• First purpose of the trials is to find the best and most efficient method for triggering the plasma for our final testing procedure.

• Secondly to trial the best combination of cleaning methods.

• Thirdly to build experience with these various techniques.

• The proposed method of comparing one technique against another is to run each trial many times and record the size of the pulse from the plasma. The heights of these pulses should fit a Gaussian. The values of the mean and width for each trial will be compared.

• Another factor could be the quality of the shape of the pulse.

Triggering the plasma• Obtain propagation of the plasma with cosmic rays.

Separate these into triggers from the five regions of the anode wire.

• Demonstrate triggering of the plasma with the UV-laser from the same five regions.

• Use lenses with different focal lengths to test triggering at different depths in the cell between anode and cathode.

• Demonstrate triggering using optical fibre rather than a lens.

Cleaning the wires with heptane

• The purpose of the tests on various cleaning methods is to try and judge what is the best combination to obtain the largest average pulse.

• Use unclean wire or deliberately contaminate the anode and see if the position of the contamination can be found.

• Try heptane to clean it.• Will this be sufficient?• Try alternatives to heptane to judge their

effectiveness.

Test the baking technique

• Build an oven and trial the baking technique.

• The nemo3 TDR reported using a temperature of 650oC.

• Bake contaminated wire and see if this will be sufficient without first cleaning with heptane.

• Try cleaning with heptane and then baking it and again.

Nitrogen jet

• Blow a jet of nitrogen along the length of a contaminated anode wire and test to see if it will propagate a plasma.

• Then take wire cleaned with heptane but will not support a plasma and see if this technique will cure the problem.

• Then take wire that has been both cleaned with heptane and baked.

Testing the tension on the wire

• As a separate problem the best method of measuring the tension of the wire during construction and in situ.

• During the wiring process a mechanical method is probably best.

• In situ an electrical method will be trialed.

• These have yet to be finalised.

Conclusion

• Need a clean environment to do these trials.• Many and varied trials to be done and will take

a lot of time. Need to get started!• Need to finalise the methods for measuring the

tension on the wires.• Could also start preparing the ground for

automatic electronic readout.• I will document the trials for circulation and

will be placed on my website.