Camilla, Sheila

We went back to ISCT6 during the commisioning time this afternoon.  We repeated the measurement done here: 54566

We also changed the lens in the path to the temporary AS air 1811 diode.  After realigning this we found that we could get a much larger signal out of the 1811.  Camilla measured 147mV of DC power on the 1811, with a transimpedance gain of 1V/mA and responsivity of about 0.75A/W this is about 196uW, enough that we could be saturating the diode.  Last time we measured the power in the path to this diode,  54636, we saw only 130uW, so there is a bit of an inconsistency there.  Not suprisingly, the RF spectrum out of this 1811 is dominated by 45MHz and harmoincs, perhaps so much that we are also having RF saturations. After demodulating at 3.125MHz, we see a large noise signal at 270kHz.  

At this point we decided to quit for today and go back to triple coincidence.