[Pol. p Target] laser duty 20%

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enhanced the FID signal by remove dirt on the chamber tube. the dirt covered the laser and it was rotated, so a clean part of the tube on the laser path.

so, we measured the 30% duty again.

after we change to 20% duty. and the result disagree with old crystal. but after changed the crystal angle, the signal agrees with old crystal.

it is strange that, we has adjusted the crystal angle during 30% duty, the optimum angle is not same as 20% duty. we have to measure 30% duty again.


[Pol. p Target] resume experiment

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after a long summer break due to lab maintain.

we check the system to see weather it gives same results before.

the Hall probe reading is weird, so we calibrate it with water NMR signal.

and we redo the 30% laser duty, found that it is small, much smaller then expected.


after discussion with my professor on my PhD topic.

i like to study the spin by nuclear scattering experiment. the polarized spin target is a good spin detector.

one possibility is on the EPR paradox and the Bell’s inequality. my professor gave me a PhD thesis on proton-neutron spin experiment on EPR.

another possibility is on the localized special relativity and quantum entanglement. since these two are strongly related by spin. my professor gave me a book on spin statistic about that.

another unclear way is through the study of spin group, Lorentz group and Mobius group. by some transformation, a 3D rotation can transform into a 2X2 matrix and then reveal that spin can have classical picture with the help of complex number. that is a suggestion that L, the orbital momentum, and S, the spin, may be the same thing. moreover, the mathematical structure of L and S are the same for s=1. can we find a counterpart of l=1/2???

[Pol. p target] laser duty 20% and 30%

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This were what we doen today.

the peaks of Fourier spectrum position seem depend on crystal angle.

[Pol. p target] laser duty 10%

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we did 10% laser duty. the result is no surprise.

since we employed Fourier Analysis, so, the Fourier spectrum has 2 peaks, separated by 60 kHz. the central frequency is 12.6 MHz.

[Pol. p Target] laser duty 5%

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my groupmate fixed the signal. it is probably the crystal angle.

thus, i continuous the laser duty 5% and done.

but before, i did not get large signal. and spent few hours on checking system. the problem is, the default FID area count from 1500 to 3000, not 800 to 3000.

the water resistivity of the laser is low. has a warning.

[Pol. p target] new crystal

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the old crystal was broken for unknown reason.

we started a new crystal and get the crustal orientation right.

we collected the data statistic, the measurement error is 2%. this small error is mainly due to large signal.

we assumed the microwave system and magnetic field does not depend on crystal. and we start the laser pulse scheme measurement.

we started with 5% duty. after a while, for unknown reason, the signal drop and gone.

[Pol. p target] checking the Hall probe

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last week, we had measured the magnetic field against water NMR frequency. However, the magnetic field calculated from the Hall probe has 10% different from theoretical value. we think that it may be due to the position of the hall probe is not on the crystal site but lower, about 50mm. and the separation of the Helmholtz coil is 150mm.

thus, we take out the crystal, and replace it with another hall probe. we found that the magnetic field was much closer to the theoretical value. Although it is closer, and the different is 0.0038 Tesla to the theoretical value. which is 1% to 2% error. Thus, we think this error is due to the horizontal position.

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