HOME ESR EXPERIMENTS LABS etc
E121 E127 E132 E125 E143 laser_cooling_2021 E142 Ê128 E146 E0052 E0018
  Laser Cooling Experiment 2021, Page 1 of 5  Not logged in ELOG logo
ID Date Authordown Category Subject
  19   Wed May 12 10:15:47 2021 Volker HannenDAQUnplugged TDC inputs for MCP front and back
To reduce the load on the VUPROM TDC, we unplugged the TDC inputs for the front and back signals of the MCP of the XUV detector.
The Anode signal is still plugged in and should be sufficient for the analysis.
  45   Fri May 14 04:50:46 2021 Team #NightGeneralScraper Tests Ion / Laser Beam
laser is 4-6mm below the ion beam.
It could be that the interaction between both beams came only from the interaction between the laser halo with the ion beam ?!
  46   Fri May 14 06:34:45 2021 Team #NightAnalysisDSG821 IP
140.181.104.108
  47   Fri May 14 06:35:55 2021 Team #NightGeneralAdjustment of Laser
we increased the height of the laser beam

TEM Settings
OffsM Ay -0,07
OffsM By -0,35

1VO scratches 6
2VO scratches 3-4
  48   Fri May 14 07:20:18 2021 Team #NightGeneralactual bunching frequency
25,82556 MHz
h = 20
  Draft   Fri May 14 07:33:42 2021 Team #NightGeneralecooler central frequency shifted relative to bunch central frequency
  44   Fri May 14 01:34:44 2021 TeamGeneralstrange XUV Anode signal
We see a strange behavior of the anode signal when we bunch the ion beam and electron cooler is on.

peak structure... ---> we play now with the bunching amplitude 

200mV
150mV
100mV ---> Peaks higher?

see attached file
Attachment 1: Screenshot_(68).png
Screenshot_(68).png
  59   Fri May 14 22:04:25 2021 TeamAcceleratorESR OPEN ; NO BEAM -> Reset cooling device
we had to open the ESR to reset a cooling device
  60   Fri May 14 22:20:37 2021 TeamAcceleratorESR Closed - BEAM #ON!
  61   Sat May 15 03:39:16 2021 TeamGeneralactual revolution frequency
frev = 1,2912735 MHz
  65   Sat May 15 09:50:31 2021 TeamRunsLaser cooling of....
H=2
H=7
H=10
H=20
H=30

We performed several scans:
Close to the bucket middle
Over the bucket
Over the bucket, jumped to the "red side" 
of the bucket and captured and cooled the 
beam again.

Laser settings:
7 times revolution frequency and 740ps 
pulses - - > 3.4 +/- 1.2 GHz

Still to do:
Switch to 240ps pulses - - > 5.8GHz 
+/-1.3 GHz

Maybe:
Switch to 117ps pulses - - > 11.0 +/- 0.8 GHz
BUT here we have less laser power (max. 50 mW right after BBO crystal, so maybe only 30 mW at the laser-ion overlap)
available. Maybe we are lucky and it is 
enough to cool also the ion beam. :) 
  73   Sun May 16 02:28:21 2021 TeamGeneral#Beam ON!
Laser specs:
pulse length -> 482ps

~75mW UV Power inside ESR (depending on laser wavelength)
  74   Sun May 16 05:09:04 2021 TeamGeneralLaser cooling with 482ps
we see laser cooling with 482ps pulse length
  75   Sun May 16 05:09:27 2021 TeamGeneralSwitch to 285ps
pulse length -> 285ps

minimum 62mW inside ESR (depending on laser wavelength)
  76   Sun May 16 05:24:00 2021 TeamGeneralLaser cooling with 285ps
we also see laser cooling with 285ps pulse length
  77   Sun May 16 06:13:46 2021 TeamGeneralSwitch to 166ps
  78   Sun May 16 07:03:07 2021 TeamGeneralLaser cooling with 166ps
We saw some indications of laser cooling @ 166ps pulse length
  81   Sun May 16 21:23:02 2021 TeamGeneralESR OPEN -> preparation for Polarisation Tests
  82   Sun May 16 22:11:49 2021 TeamGeneralLaser Polarisation values
maximal transmission of PBSC (257/514 pbsc was used in combination with xlp12 detector and visual on a screen):

L/4 @ 276° & L/2 @ 348°                -->   p-polarized light


L/4 gleich auf 276° & L/2 auf ~19°     -->   s-polarized light
current position 22:15 p.m.

now we have some fun ! :D
  83   Mon May 17 08:05:42 2021 TeamGeneralEnd of beamtime
~ 8 a.m.
ELOG V3.1.5-fc6679b