Description

Page : 1816

Sondrestrom Lidar Operation Log

Operator(s) : Christian Have Pedersen
Purpose : Trouble shooting 10x240Hz noise signal on Na channel
Date(s) : 070327 - 070328
File(s) : L20070323_002 - L20070327_000
Comments : This experiment has been carried out without any lasers firing, roof hatch closed
and no artificial light inserted in telescope frontend.
The 10x240Hz noise signal is apparently not present when 589 PMT is capped
(dark count).
The 10x240Hz noise signal is present when uncapped and no other light than the
display light from the sr430 rack.
Following troubleshooting has been carried out without any change of the noise
signal on the NA channel:
-Daq. on alternative SR430.
-Replaced 589PMT signal out cable
-PMT signal amplification on alternative channels on the two sr445.
-Swapped chopper power and control signals (between 532 and 589 chopper)
-Various cable routing.

Logfile : I2803070.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) : 070327 - 070328
File(s) : L20070323_002 - L20070327_000

Files	Time [UT]	Comments	Cnt	S	Ope
L20070323_002	23:38:09	Start of experiment		0	cp
L20070323_002	23:38:16	Dark count measurements. Want to see if 10x240Hz is present	0	0	cp
L20070327_000	23:47:48	Both 532 and 589 PMT's capped. Noise level high on Na channel		0	cp

L20070327_000	23:48:44	Uncapped 589 PMT. Now the 10x240Hz noise signal is present		0	cp
L20070327_000	23:51:13	NB.: This experiment is without lasers firing and roof hatch is		0	cp
		closed. No light source inserted at telescope frontend.
		No lights in LIDAR room. RX cabinet NOT shielded.
		Only light is from the SR430 rack.
L20070327_000	23:56:15	532 PMT uncapped.	0	0	cp
L20070327_000	23:58:31	Pausing daq. Will try some ideas with choppers etc.		0	cp
L20070327_000	01:12:40	Have been trouble shooting hardware. Tried swapping choppers,		0	cp
		SR430 and various alternative cable routing. Replaced 589 PMT
		signal out cable. No change in how the noise signal appeared
		on the Na channel. Will have to evaluate results and retry
		the search.
L20070327_000	01:22:11	End of experiment		0	cp