Changed GTEDSAH Rechts to 10mm

• The laserscan tab shows each observable plotted against the predefined wavelength setpoints now.
  
  
• The Kobra set wavelength shows the actual setpoints now and not measured wavelengths.
  

See attached

At around 15:00, The slits in the TE line were changed to :
TE4DS5HL -12 mm -> -20 mm
TE5DSAH 0 mm -> +15 mm

started taking data again

started at 15:40  
h=1  

file names 
229Th7821 DAQ 1  607 MB
229Th0082 DAQ 2  820 MB 

stopped at 16:25 


The laser was not really properly scanned. 
This was mainly a test run to see if everything was working. 

The problem - "discovered" by Volker and Ken - of the high dark countrate of the Cu PMT has been solved. 

(when the Cu mirror was moved in, the dark countrate was very high ... also without ion beam) 

I asked Graziano Savino to check the vacuum gauges along the target side of the ESR (west side). 
The gauges at the laser window sections (which we do not use here!) - NW and SW - were still on. 
Volker remembered that, in the past, for the lowest dark countrate at the Cu PMT --> ALL GAUGES MUST BE SWITCHED OFF. 
Graziano turned them off and Sebastian and I checked the Cu PMT rate in DAQ1. 

Attached you can clearly see the difference: from 7500 cps to 400 cps. 

When the Cu mirror is retracted the dark countrate is 200 cps.  

Danyal

PS The slow increase in one plot is due to the fact that Graziano switched on the light in the ESR. 

below are my notes concerning laser timing / Q-switch start

The bunch HF is now fed through a delay to shift the stop trigger relative to the PMT signal. The delay generator is placed directly after the CFG and before splitting the signal for the two DAQs. The relative timing of both DAQs was not changed.

The timing for h=1 has been set up 

The time window is now twice as large as before! 
This means that we see the same ion bunch twice. 

(150 bins = 1 turn in the ESR) 

The PMT signal is exactly in between two cycles + the extra flight time (3 bins = 10 ns) from target to PMT north. 

NTCAP is started for the data taking.

Carrier Frequency: 242.02 M
IQ Rate (S/s): 10 M
Reference level (dBm): -30

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We changed the fiber to the wavemeter. The third fiber worked best and we could operate the WM at low exposure times, i.e., below the laser repetition rate. We used the neutral density filter to adapt the laser power that only one laser pulse is measured by the WM each time (Exposure time =34ms)

This way, there are no frequency jumps. The jitter is slighly different at each wavelength which was ~5GHz peak to peak.


We optimized the fiber coupler and slightly optimized the jitter to <4GHz.

After changing to h=1
The frequency manipulation #5: f=242.021487MHz (124th harmonic) [no bunching]
Manipulation #7: f=242.021812 MHz [with bunching]

NTCAP is stopped. Sergey will now set an ion bunch instead of two in the ESR.

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\IQ_2022-04-08_09-39-33