[[email protected]]

Hello, I am having trouble getting the signal from the detector to
appear on the computer (by using a DAQ board). So the experimental
setup consists of Dye laser (visible light), pumped by a ND:YAG laser
which initially triggers a SRS DG-535 pulse generator. The DG-535
then triggers the DAQ card (PCI-9812) and a gas sample separately (for
these purposes the gas triggering should not be important). The PMT
detector of laser light (Hamamtsu module H6780-04) is connected to the
same DAQ card, but the detector is not triggered at any time in the
sequence, so it is constantly "ON." When I run the experiment I do
not see a "laser" signal from the detector to the DAQ in the labview
program. If I connect the detector to an oscilloscope I do see a
signal, but it shows up before the initial laser triggering. The
laser signal seems to be too fast (10 ns) for the DAQ card (limit 50
ns or 20MHz), so is there any way to retard the signal and be able to
capture it with the current setup/DAQ card. thanks for any help.

[John Fields]

On Wed, 28 Jan 2009 15:24:04 -0800 (PST),
wrote:

Hello, I am having trouble getting the signal from the detector to
appear on the computer (by using a DAQ board). So the experimental
setup consists of Dye laser (visible light), pumped by a ND:YAG laser
which initially triggers a SRS DG-535 pulse generator. The DG-535
then triggers the DAQ card (PCI-9812) and a gas sample separately (for
these purposes the gas triggering should not be important). The PMT
detector of laser light (Hamamtsu module H6780-04) is connected to the
same DAQ card, but the detector is not triggered at any time in the
sequence, so it is constantly "ON." When I run the experiment I do
not see a "laser" signal from the detector to the DAQ in the labview
program. If I connect the detector to an oscilloscope I do see a
signal, but it shows up before the initial laser triggering. The
laser signal seems to be too fast (10 ns) for the DAQ card (limit 50
ns or 20MHz), so is there any way to retard the signal and be able to
capture it with the current setup/DAQ card. thanks for any help.

---
There may be, but I'm confused as to what makes what happen and what's
hooked up to what.

If you could make a block diagram of how your system's hooked up
(something like this, using a non proportional font like Courier):


[Nd:YAG LASER]- -[DYE LASER]- -[H6780-04]--
|
|
[DG-535]---[PCI-9812]

I'm sure at least one of us could can help you come up with a solution.

BTW, if you show the optical paths using - - and the electrical paths
using --- that would help to make things clearer.

JF

[Cesar]

On Jan 29, 3:35*pm, John Fields wrote:
On Wed, 28 Jan 2009 15:24:04 -0800 (PST),
wrote:

Hello, I am having trouble getting the signal from the detector to
appear on the computer (by using a DAQ board). *So the experimental
setup consists of Dye laser (visible light), pumped by a ND:YAG laser
which initially triggers a SRS DG-535 pulse generator. *The DG-535
then triggers the DAQ card (PCI-9812) and a gas sample separately (for
these purposes the gas triggering should not be important). *The PMT
detector of laser light (Hamamtsu module H6780-04) is connected to the
same DAQ card, but the detector is not triggered at any time in the
sequence, so it is constantly "ON." *When I run the experiment I do
not see a "laser" signal from the detector to the DAQ in the labview
program. *If I connect the detector to an oscilloscope I do see a
signal, but it shows up before the initial laser triggering. *The
laser signal seems to be too fast (10 ns) for the DAQ card (limit 50
ns or 20MHz), so is there any way to retard the signal and be able to
capture it with the current setup/DAQ card. thanks for any help.

---
There may be, but I'm confused as to what makes what happen and what's
hooked up to what.

If you could make a block diagram of how your system's hooked up
(something like this, using a non proportional font like Courier):

* *[Nd:YAG LASER]- -[DYE LASER]- -[H6780-04]--
* * * * * |
* * * * * |
* * * *[DG-535]---[PCI-9812]

I'm sure at least one of us could can help you come up with a solution.

BTW, if you show the optical paths using - - and the electrical paths
using --- that would help to make things clearer.

JF *

ok, let see, so with JF's format of optical and electrical paths:
[Nd:YAG LASER]- -[DYE LASER]- -{Vaccum Chamber/Sample}- -[H6780-04]
| |
| |
| [GPIB] | - - [gas pulse valve
controller] |
- - [DG-535]- - - - - - - - - - -|- - - - - - - - - - - - -
- - - - - - - - - - - - - - - - - - - - [PCI-9812]

So the Nd-YAG is the initial trigger, the DG-535 then take this
trigger and sends the signal to the PCI-9812, which then "looks" for a
another signal coming from the H6780-04. The DG-535 also triggers the
pulsed gas valve that sends the sample into the vacuum chamber. The
computer software control the dye laser output wavelength with the
GPIB connection. Any help would be appreciated, thank you.