A:
The display will then sample at close to its maximum frequency. For instance when measuring 10 KHz with a PD10 head and Nova II where the maximum frequency for every pulse on the Nova II is 4 KHz: in this case, the Nova II will pick out pulses at a rate of close to 4 KHz and sample them, i.e. the Nova II will record 40% of the pulses.
A:
It can work with any heads in dual mode where they are operating
separately but for ratio or difference it can only work
with pyro vs. pyro or thermal/photodiode vs. thermal/photodiode.
A:
This can sometimes happen when the battery of the display
is completely discharged and then the charger is plugged
in. The display is powered up but the contrast voltage on
the LCD is not functioning, so it looks as though it is
off; and usually the backlight switches on and off normally.
The solution is to first switch OFF the display properly
by pressing the On/Off button for 4-5 seconds, and then
switching it back ON by momentarily pressing the On/Off
button, as normal.
The display will also fail to operate if you attempted to download
a software upgrade and there was a malfunction in the download,
see the question "Can I upgrade " below.
A: The display software can be upgraded by the customer using Ophir's USBI
PC application available for download from the Ophir
website.
1.
Attach the display to your PC with the
USB cable provided with the display.
2.
Go to the bottom
of the USBI
page and download the firmware for your display
3.
Run the USBI
PC application
4.
Select your display device and press upgrade
5.
Application
will open the "Device Upgrade Screen"
6.
Follow all
the on-screen instructions to successfully reprogram
the display.
If
the field-upgrade process fails (example, unplug of
the USB cable during the upgrade), the display will
not function properly. Therefore, when turning on
the display the user gets a blank screen. Note: The
display can still communicate with the PC. Try to
reinstall the display software as described above.
A:
The Ophir specification on accuracy is in general 2 sigma standard deviation. This means, for instance, that if we list the accuracy as +/-3%, this means that 95% of the heads will be within this accuracy and 99% will be within +/-4%
A:
If the power is P and the diameter of the beam is D then
the power density is P /(.785 * D2) . If it is a pulsed
laser and the energy is E, the repetition rate is R and
the diameter is D then the power density is E*R/(.785 *
D2), The energy density is E/(.785 * D2)
A:
If the calibrated wavelength is W1 and I want to measure
at wavelength W2 then I look at the relative sensitivities
on the curve at W1 and W2 and calculate as follows: Sensitivity
at W1: s1 Sensitivity at W2: s2 When instrument is set to
W1 and I measure W2, then multiply reading at W2 by s1/s2
to get correct reading at W2.
A: There are in general no losses associated with using our fiber optic adapters. The adapters are simply jigs to hold the fibers in the right location vis a vis the measuring heads. They do not transform the beam coming out from the fiber in any way.
A: We have done some in-house tests with LabVIEW 8.2 and the USBI VI's seem to be compatible.
We've also had other customers working with our VI's in LabVIEW 8, so far with no clear issue that we know.
In fact, LabVIEW usually offers/suggests that it will automatically update the VI's when opened with a newer version of LabVIEW.
A: If you are planning on communicating with the instrument via RS232 (for those instruments having an RS232 interface), then the StarCom manual included on the CD-Rom includes a full description of device communication and commands.
If you are planning on communicating with the instrument via USB (for those instruments having a USB interface), then in the Installation Directory of the USBI PC application, you'll find a sub-directory called Automation Examples that contains within it examples of how to use the USBI ActiveX to communicate with the device. It also contains a document describing the various commands.
A: Device responses take the form 1.234 (a period distinguishes between the integer and fractional part of a real number). This may not match the settings of the computer upon which the VI is running. For example, many European countries use a comma (",") in place of a period (1,234). This causes the LabVIEW VI to not "understand" the devices's response.
(Go to http://zone.ni.com/devzone/conceptd.nsf/webmain/99d21982a9f954e186256a5b0057919e the section on Period and Comma Decimal Separators for National Instrument's explanation)
Solution: LabVIEW allows the User to override the local regional settings of the computer within the LabVIEW environment. To do so
A: At Ophir, we developed USB drivers for use with our USBI PC application. National Instruments USB drivers work in a different manner. Ophir drivers are not compatible with NI VISA communication. NI drivers are not compatible with Ophir's USBI PC application.
SwapINF configures Windows to associate the Ophir device with NI-VISA's usb driver (NIVIUSBK.sys) when LabVIEW is selected. It configures Windows to associate the Ophir device with the appropriate Ophir usb drivers (windrvr6.sys) when USBI is selected
REMINDER: To work with LabVIEW, NI-VISA 3.01 or higher (from National Instruments) must also be installed.
Click here to download
the self-extracting "SwapINF Utility". Run the SwapINF utility
and follow the on-screen instructions to configure the USB speaking
device (USBI or Nova-II) for LabVIEW or USBI PC work as desired.
A: The Ophir integrating sphere heads, models 3A-IS, 3A-IS-IRG and F100A-IS have a white diffuse reflecting coating on the inside of the integrating sphere. The sensitivity of the head is quite sensitive to the reflectivity of the coating. If the coating absorption goes up 1%, it can cause a 5% change in reading. Therefore, care must be taken not to soil or damage the white coating of the heads. Also it may be a good idea to send the heads for recalibration yearly.
A: The BC20 has a peak measurement and hold circuit
which measures the peak power on the detector and holds
it. Therefore when a beam is scanned over the detector,
when the beam is on the detector it goes up to a peak which
corresponds to the same power the detector would measure
if the beam was stationary and therefore the BC20 reads
the correct power whether the beam is scanned or not. In
order for the BC20 to do this, the beam must be on the detector
(of size 10x10mm) for at least ~13µs and therefore this
limits the scanning speed on the detector to 30,000 inch/s.
A: No. We have carefully designed them that there
are no such effects from multiple reflections. This is because
we use only absorbing or diffusing type elements.
A: The reading jumps around a lot but if you use
the average function and the pulse energy does not exceed
the ratings in the head catalog, the reading should be okay.
A: All Ophir pyroelectric heads can measure average power with Ophir displays. The instrument measures the number of pulses each second and divides the energy reading by the pulse rate. If the pulse rate is constant, then the accuracy of power measurement will be the same as the energy accuracy since the pulse rate measurement is very accurate.
A: No, even though the scope adapter allows viewing of the actual electrical pulses coming out of the head and thus looking at higher repetition rates, the display is still needed to supply power to the head and to enable changing of ranges.
A: Ophir pyroelectric heads have a positive temperature coefficient of 0.2% per degC which means that if the head heats up 10 degrees, the reading will be 2% high. The PD10 and PD10-pJ heads use photodiode detectors so their temperature coefficient is the same as the PD300 heads as listed on the PD300 pages of the Ophir catalog.
A: Our energy detectors measure the total energy deposited within a time window defined by the pulse width setting selected via the Smart Display. There is no minimum pulse width limitation since we are measuring the energy deposited, not power or peak power.
A: There is no reason not. Theuser will have to make
a vacuum tight 15 pin feedthrough to get the signal out.
We also sell a vacuum flange for the PE50 head
A: If the vacuum is not ultra high and the system
is unheated, yes. The user has to rewire the 15 pin plug
into a vacuum feedthrough or if possible, use the wireless Quasar interface.
A: We specifiy the linearity as +/-2% for >10% of
full scale. One can get reasonable accuracy down to 5% of
full scale but at 3% of full scale the readings will be
guaranteed to be considerably off. Therefore, the user should
always use the meter on the lowest scale that he can read
on and if there is a discrepancy between a particular heading
on the higher and lower scale, the reading on the lower
scale is correct.
A: The head will stop integrating after 50us and
will lose part of the pulse. It will then read low. This
is relevant to the PE10 which only has the short setting
(in the case of PE10 it is ~30us).
A: The display simply decides it is time for a sample
and takes the next pulse that comes after that time, e.g.
if it samples at 400 Hz, then every 1/400th of a second
it is ready to take the next pulse that comes along.
A: The problem is most probably acoustic vibration. Pyroelectric heads are sensitive to vibration as well as heat. On the most sensitive scales of sensitive heads such as the PE9 and PE10, they may be very sensitive to vibration. The solution is to put an acoustically absorbing material such as a thin piece of soft foam plastic under the base of the head to damp out any vibration.
A:
The USB Interface was designed to communicate with any PC.
However, we provide an application as well as an ActiveX
for Windows Operating Systems only. The USBI can be controlled
through our ActiveX in Visual Basic, Visual C++, and LabVIEW.
You can fully control the device with our extensive command
set (provided with the installation package). Documentation
and Examples are found in the "Automation Examples" sub-directory
of youe USBI installation directory
A:
The USB interface can support up to 10 heads simultaneously.
Each head requires one USBI device. Note: Most PC's have
2 to 4 USB ports. To attach more USBI devices you must use
a USB 1.1 compliant Hub
A:
The Analog output for Pyro head can measure up to 10 Hz.
Therefore if you want to measure at a higher frequency (up
to the maximum frequency of the head), you can connect the
Scope Adapter for Pyro Head (Ophir P/N 1Z11012). This adapter
provide
a BNC output to scope to see every pulse up to the maximum
head frequency.
A:
From USBI version 1.11 and higher, we support customer tailored
OEM features as well as standard application features. If
OEM is selected, the user will be asked to enter his OEM
code. The OEM code is specific to each type of tailored
interface ordered. If the code is entered, a special installation
(with the requested features) will be performed. For all
other customers, the Standard installation is the correct
choice.
A: In general, the dynamic range, i.e. the ratio of maximum useable power to minimum useable power of Ophir OEM heads is 40:1. If greater dynamic range is desired, Ophir OEM RS232 heads are available with several selectable ranges.
A: The damage threshold of thermal heads does depend on the power level and not only the power density because the sensor disc itself gets hotter at high powers. For instance, the damage threshold of the Ophir broadband coating may be 50KW/cm2 at 10 Watts but only 10KW/cm2 at 300W. The Ophir specifications for damage threshold are always given for the highest power of use of a particular head, something which is not done by most other manufacturers. This should be taken into account when comparing specifications.
A: We publish a nominal damage threshold for most
of our thermal BB heads as 20KW/cm2. Other manufacturers
may quote higher numbers than this. In actuality, in one
to one tests against competitors, our heads show a higher
damage threshold but the actual damage threshold depends
on the total power as well as the power density. For very
low powers such as 30W, the damage threshold can be as high
as 50KW/cm2 and at high powers such as 5KW, it drops to
3KW/cm2. The Ophir head finder program takes account of
these variations in its calculations.
A: The damage threshold curve in the heads catalog
only goes down to 1ns but the energy damage threshold is
similar for shorter pulses. You can use ˝ of the ns value
for fs pulses i.e. the absorber damages twice as easily.
A: The 3A-P actually absorbs about 85% at 10.6µm
and therefore it can be used to measure weak CO2 lasers.
Note the low power damage threshold, however, of 50W/cm2.
A: UV: 193 - 350nm, VIS: 350 - 850nm, NIR: 850 -
3000nm, CO2: 10.6um. Newer heads have the regions explicitly
where the laser settings are: <.8µ, .8-6 and 10.6
A: For HE between 0.625 and 1um and HE1 past .755um,
the window transmits too much and the absorption drops by
~10%. Because of this, the thermal heat sink compound behind
the absorber can dry out. If the power and energy is kept
to 1/10 of maximum and the calibration is not important,
the head can be used in this spectral region.
A: Yes. To do so, the smart plug should be attached
to the Ophir smart head to BNC interface (Ophir P/N 1Z11010)
and the output should be put into an amplifier with input
impedance set to ~10KOhm.
A: Thermal heads for intermittent use such as models
30(150)A, L40(150)A etc. can be used up to the powers in
parenthesis for a period given approximately by the following
formula: The rule of thumb is that you can use the head
for 1 minute/watt/cm3 of head. So for 150 watts for 30(150)A
you have 1minute*165cm3/150watt =~ a little over one minute.
The head finder program calculates the allowability of intermittent
use when the user fills out the choice for duty cycle.
A: It is flat for <750nm and for >900nm but can vary
+/-2-3% between those regions. Since it can vary in either
direction, this information cannot be put in the spectral
graph.
A: Water cooled heads will not work properly at all
unless the head is filled with water to make thermal contact
between the disc and head. If the head is filled with water
and the input and output connectors are stopped up, then
the head can be used for a short time without water flow
or at much reduced power continuously.
A:
In normal (CW) operation, the CCD is automatically triggered
to start a measurement. At the end of the integration time,
the voltage for each pixel is read out of the CCD serially
and converted by the A-to-D into a 12-bit digital value
When the PLD has finished reading all the pixels of the
CCD it signals to the PC that data is ready to be read.
After the PC has finished reading the data, the next available
measurement of the CCD is again stored and the cycle continues.
In Pulsed Mode for Long Pulses ( >5µs ), the CCD is triggered
by the trigger circuit instead of automatically as for CW
mode. As the pulses are long, their intensity can be read
by the CCD after it is triggered, by setting the appropriate
shutter time for the length of pulses.
In Pulsed Mode for Short Pulses ( <5µs ), the same method
as for long pulses cannot be used because once the circuit
is triggered, the pulse has already finished. Therefore,
the CCD is triggered automatically as with the CW mode,
but after each measurement of the CCD, the PLD checks to
see whether the trigger circuit received a pulse while the
CCD was measuring. If so, the data is and the cycle continues
as normal; otherwise a new CCD measurement is made.
In most cases of pulsed light sources, CW operation will
be sufficient (and the intensity can be adjusted by adding
filters or reducing the Shutter Time). In that case, the
Shutter Time should be adjusted to capture a few pulses
of light for each CCD integration, to avoid having 'empty'
measurement cycles where no light is captured by the CCD.
In the case that the pulses are slow, and/or the Shutter
Time would have to be excessively long to guarantee capturing
at least one pulse each time, the Pulse Mode operation can
be used instead.
A:
What determines this is the amount of power getting through
the slit of size 5µm x 3mm so as long as the light source
is larger than 3mm to overfill the slit, the power density
is what determines this.
At a typical wavelength of 670nm, the reading reaches full
scale where the exposure time x power density ~ 2E-7 Watts
* sec / cm2.
Since the longest exposure time is 7s, and we can easily
read 1/100th of full scale, the lowest power density on
the slit will be ~ 0.5nW/cm2. If the input is from a fiber,
you can use the SMA fiber input accessory (Ophir P/N 1Z08205)
with focusing lens (Ophir P/N 1G01236) to focus the fiber
output onto the slit.
Since the shortest exposure time is 28µs, the highest power
density we can read is ~ 1mW/cm2. In practice, we can always
spread the beam as much as we want or reflect it off of
a diffusing surface into the WaveStar so there is really
no limit to how high a power we can measure.
A:
For 905nm the single shot energy threshold is ~ 100nJ/cm2
falling on the input slit of 5um x 3mm. At 1030 - 1100nm
the sensitivity will probably be 10 to 100 times less.
A:
In response to growing customer demand, WaveStar is being
upgraded to include ActiveX controls. This will allow other
applications (such as LabVIEW, LabWindows, Visual Basic,
Visual C++) to control WaveStar parameters and collect measurements
in real time. This will be included in the next release
of WaveStar (February 2002).
A:
When the power calibration of the WaveStar is activated
by pressing the P icon, the software puts in a calibration
factor for each wavelength which compensates for the variations
in sensitivity of the WaveStar at various wavelengths and
produces a spectral curve which has the correct relative
intensity values. For instance, if the light at one wavelength
has twice the intensity of another, the display will show
a relative height difference between the two wavelengths
of a factor of 2.
The correction curve is generated by exposing the WaveStar
to a NIST traceable calibrated wide band light source. The
software compares the known relative intensity values of
the lamp spectral curve with the values produced by the
WaveStar and generates a correction curve.
A:
You absolutely can use the Quasar to do data collection, but how similar the process will be depends on the type of head being used. If you are using Ophir Thermopile and Photodiode heads, these work much the same way on the Quasar as they do on the Nova-II. You should be able to collect data in much the same way as you do today. You just need to establish a Bluetooth connection, open a COM port on the PC, and then can send commands as with the Nova II. You might need a small amount of low level code just to send/receive the commands and strip the prefix/suffix, which is not difficult. Ophir-Spiricon tech support can help. If you are using Pyroelectric heads, however, you will have to wait for the ActiveX package to be released, because the communications are very different from the Nova II, and you will not be able to handle the data on your own. Your data collection software might be somewhat different, as well, but it will function similarly to the Pulsar. ActiveX for the Quasar is tentatively scheduled for the beginning of 2009. Note also the "every pulse" data rate on the Quasar with a Pyro head will be lower than on the Nova II; we guarantee 500 pulses/second in our spec.
A:
The Quasar is no different than the other instruments that have electronic components: it requires annual recalibration. But it’s up to the customer whether to do this or not. We know that the calibration of the instruments degrades somewhat over time, as shown in the datasheet. This may or may not affect your particular application. To maintain compliance with ISO and other standards, we highly encourage annual recalibration.
A:
Unfortunately, this is not possible, at this point. The Quasar can establish a connection with only one host PC at a time. If you connect to the laptop in the clean room, you will not be able to then connect to another PC in an adjacent office; the Quasar will be locked out. You would have to cut the connection on the laptop before you could establish the connection to the second PC. On the other hand, the beauty of the Quasar is that you can ONLY connect to the second PC in the adjacent room, outside the clean room, and log all the data from there. There is no need for a laptop in the clean room, unless of course, if you need to observe data while in there, in which case you would have to do the above.
A:
In actual testing done at customer sites, using the high power option, there was not a place within 100 meters that we could not connect, including going through multiple walls that were made of drywall. The only time we lost transmission was when the walls were made of concrete or we had to pass through some metal doors. With normal labs and offices the signal went right through. In several cases, including a solar power scribing application where windowed doors had to be closed, we were getting a continuous connection as we walked around the spacious building into offices and labs. With the standard range option, the range should be about 1/3 of this i.e. 30 meters.
