Chapter 5 Operation; Introduction - Princeton Instruments PhotonMAX System Manual

Operation

Introduction

Once the PhotonMAX camera has been installed as explained
in the preceding chapters, operation of the camera is
straightforward. In most applications you simply
establish optimum performance using the Focus mode
(in WinView/32 or WinSpec/32, for example), set the
target camera temperature, wait until the temperature has
stabilized, and then do actual data acquisition in the
Acquire mode. Additional considerations regarding
experiment setup and equipment configuration are
addressed in the software manual.
During data acquisition, the CCD array is exposed to a
source and charge accumulates in the pixels. After the
defined exposure time, the accumulated signal is readout
of the array, digitized, and then transferred to the host
computer. Upon data transfer, the data is data is displayed
and/or stored via the application software. This sequence
is illustrated by the block diagram shown in Figure 14.
Whether or not the data is displayed and/or stored
depends on the data collection operation (Focus or
Acquire) that has been selected in the application
software. In WinView and WinSpec, these operations
use the Experiment Setup parameters to establish the
exposure time (the period when signal of interest is allowed to accumulate on the CCD).
As might be inferred from the names, Focus is more likely to be used in setting up the
system (see the "First Light" discussions) and Acquire is then used for the collection
and storage of data. Briefly:
•
In Focus mode, the number of frames and accumulations settings are ignored. A
single frame is acquired and displayed, another frame is acquired and overwrites the
currently displayed data, and so on until Stop is selected. Only the last frame
acquired before Stop is selected can be stored. When Stop is selected, the File Save
function can be used to save the currently displayed data. This mode is particularly
convenient for familiarization and setting up. For ease in focusing, the screen refresh
rate should be as rapid as possible, achieved by operating with axes and cross-
sections off, and with Zoom 1:1 selected.
•
In Acquire mode, every frame of data collected can be automatically stored (the
completed dataset may include multiple frames with one or more accumulations).
This mode would ordinarily be selected during actual data collection. One limitation
of Acquire mode operation is that if data acquisition continues at too fast a rate for it
Chapter 5
Incoming photons
Camera
EMCCD
Preamp Electronics
Analog to Digital
Converter
Digital processor
PCI Interface
Computer
PCI Interface
Display Storage
Figure 14. Block Diagram of
PhotonMAX System
29