We continue to find what gives high freq. perturbation.
The laser starts at 92 KW it is stable and locked to the RF. NO high freq parturbation.... With the machine off. (30 min of lock)
We put now the machine ON (All in warming exept pulsed elements)... => the system is very stable NO delock, NO high freq perturbations. The operator can even go to toilet during the operation... it's a very big improvement!!!
Now we continue with the e-beam production.... => when we put ON the Kikers wtih the rest of the machine (no electrons yet) some perturbations are observed and delock also.... but no really high freq perturbations juste very big 20 Hz like ones (at 10h30). Some people oh PERLE are in the igloo now. In any case it was easy to relock and it is very stable now.
10h50 some 40 Hz perturbation and delock.... and very big 20 Hz perturbations.... some delock arrived but not really high freq.
!!!!!!! PERLE PEOPLE MOVES LE PONT SINCE 10H30!!!!! CORRESPONDING TO DELOCK!!!
That means that the system is stable with all the maching On (but NO electrons).
So in the afternoon we will put the electrons and continue the investigation of stability.
I restart the laser after lunch with electrons in the machine. I have lost 7 KW of power.... and the lock parameter changed (P gain 0.05-> 0.03)
Je vois passer des hautes freq!! J'ai retrouvé 92 KW avec l'alignement qui avait bougé visiblement!! But the PID parameters are still 0.03.
I see a little bit Hig frq perturb but the laser dont delock. Also bigger high freq perturbation with delock. electrons effect or alignement problems??
We change the frequency for 50MeV. Delta freq = 3.6kHz so dela cavity lenght -1.1mm
We have electrons and we lock much better than before to add the amplifier to enlarge PID range.
We observe some high freq perturbations but the PID compensate and we have almost no delock!!
In conclusion: high freq perturbations dont come from the machine without electrons. The presence of the electrons is associated to some high frq perturbations but the new feedback system can compensate them and delock are rare but we have some with electrons.
Globaly the system is much better
Daniele |