Description

Page : 1816

Sondrestrom Lidar Operation Log

Operator(s) : Christian Have Pedersen
Purpose : Background measurements. Verifying effect of adjustments made to choppers.
Date(s) : 070417 - 070417
File(s) : L20070416_000 - L20070417_000
Comments : A 2.4 KHz noise signal has been present in LIDAR measurements for a while. The
noise source has been identified as being the light from the phase lock indicator
(LED). Adjustments has been made to the choppers (Rayleigh and Sodium).
Furthermore the 'cap' on the sodium PMT has been improved, so that a reliable
dark count can be obtained.
Logfile : I1704070.log

Setup:0

Page : 1817
[0]
front end Iris=not_installed
Rayleigh System=On
Rayleigh Field stop=0.5mm
Rayleigh path attenuation=0dB
Dye System=On
Sodium Field stop=0.5mm
Etalon=Out
Daystar=Out
Polarizer=In
HalfWave Plates=Tracking
Rayleigh Filter=2:532(.5nm)
Rayleigh seeding=off

Logsheet:0

Page : 1818

Sondrestrom Lidar Operation Log

Log Sheet 1 of 1
Operators : Christian Have Pedersen
Date(s) : 070417 - 070417
File(s) : L20070416_000 - L20070417_000

Files	Time [UT]	Comments	Cnt	S	Ope
L20070416_000	22:19:19	Start of experiment	0	0	cp
L20070416_000	22:20:28	Starting with dark counts		0	cp
L20070417_000	22:23:30	Dark count on sodium channel is not 'rubbish' anymore.		0	cp
		This is due to the new cap on the PMT.	0
L20070417_000	22:25:24	60 dB attn. is inserted in the sodium channel for this background		0	cp
		measurement.
L20070417_000	22:28:47	Now removing the cap on Rayleigh PMT	0	0	cp
L20070417_000	22:33:24	20dB attn. in sodium path and 10 dB attn. in Rayleigh path.	8197	0	cp
L20070417_000	22:34:41	The choppers has been out of the RX cabinet and clearly they		0	cp
		need to be adjusted. The 2.4 KHz noise is nowhere to be seen.
L20070417_000	22:42:54	Rayleigh chopper delay adjusted.	-100	0	cp
L20070417_000	22:58:32	Sodium chopper delay adjusted	-74	0	cp
L20070417_000	22:59:16	2.4 KHz noise interference is not in count profile any longer.		0	cp
L20070417_000	23:01:16	End of experiment	-79	0	cp