900-1100 nm 120 kW Water-Cooled Thermopile Sensor with Ø200 mm Aperture Deflecting Cone

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Overview

The 120K-W is a water cooled thermal power/energy laser sensor is designed for very high powers with a 200 mm aperture. It has dimensions 520 x 545 x 750 mm. The 120 kW laser power meter can measure power from 10 to 120 kW and is designed for a beam expanded to 100 mm diameter to hit its deflecting cone and is calibrated at 1070 nm. Applications include laser weapon measurements and laser measurement for semiconductor lithography processes.

900-1100 nm spectral range with deflecting cone
Water-cooled for 10 to 120 kW average power measurement
200 mm Diameter Aperture
Calibrated at 1070 nm

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Products

		Compare	Model	Compatibility	sortOrder	rankScore	ranking	Drawings, CAD & Specs		Absorber Type	Aperture Size	Minimum Power	Maximum Average Power	Availability	Featured Item	Price		Brand
		7Z02691 120K-W Thermal Laser Power Sensor, BB Type, 10-120 kW, Ø200 mm, 900-1100 nm, Water-Cooled In Stock	7Z02691 120K-W Thermal Laser Power Sensor, BB Type, 10-120 kW, Ø200 mm, 900-1100 nm, Water-Cooled	UNIVERSAL	0.0	1.0	0.0		0.0	BB - Broadband general purpose	Ø200 mm	10000 W	120000 W	In Stock				Ophir

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Software

WaterFlowMeter PC Application

Software: WaterFlowMeter PC Application
Power measurement based on water temperature and flow rate.

Firmware: Firmware of sensor can be upgraded via WaterFlowMeter PC application.
To download the firmware file go to: "Help/New Firmware" screen in WaterFlowMeter PC Application.

Note: When running the WaterFlowMeter PC Application, the Water Flow Meters (6K-W & 120K-W) are connected directly to the PC via supplied RS232 cable. If you want to use the Water Flow Meter with an Ophir power meter or with an Ophir interface with StarLab, the sensor operates as a standard thermal sensor measuring power only.

Software

WaterFlowMeter PC Application

Software: WaterFlowMeter PC Application
Power measurement based on water temperature and flow rate.

Firmware: Firmware of sensor can be upgraded via WaterFlowMeter PC application.
To download the firmware file go to: "Help/New Firmware" screen in WaterFlowMeter PC Application.

Specifications

Product Name

120K-W
Absorber Type

BB - Broadband general purpose
Aperture Size

Ø200 mm
Spectral Range

900-1100 nm
Minimum Power

10 kW
Maximum Average Power

120 kW
Backscattered Power

Less than 1%

Cooling

Water
Dimensions

520 x 545 x 750 mm (LxWxD)
Cable Length

10 m
CE Compliance

Yes
UKCA Compliance

Yes
China RoHS Compliance

Yes

Specifications

Product Name

120K-W
Absorber Type

BB - Broadband general purpose
Aperture Size

Ø200 mm
Spectral Range

900-1100 nm
Minimum Power

10 kW
Maximum Average Power

120 kW
Backscattered Power

Less than 1%

Cooling

Water
Dimensions

520 x 545 x 750 mm (LxWxD)
Cable Length

10 m
CE Compliance

Yes
UKCA Compliance

Yes
China RoHS Compliance

Yes

Features

Choosing a Thermal Sensor

In this short “Basics” video we review the use – and selection - of thermal sensors for measuring low, medium and high laser powers.

Sensors for Measuring Laser Power

In this short "Basics" video we review in general how one goes about measuring laser beam power, so that you'll have a clear understanding of what the different sensor types are, and when to use each type.

Measuring Very High Power Laser Beams

Laser beams with powers of many tens of Kilowatts are becoming more and more common in today's applications, industrial as well as research. This video will discuss the technical challenges in measuring such lasers, and will show you a range of solutions now available from Ophir for measuring up to 100KW -- safely, and accurately.

Water Cooled Sensors: Things to Look Out For

Water cooled sensors are commonly used when measuring laser beams of more than a few hundred watts. In this video, you will learn about some critical issues you need to consider when using water cooling, such as water temperature, water flow rate, and corrosion prevention.

Thermal Sensor Calibration

As the spectral sensitivity of the absorber used for the power and energy measurement is not fully linear, Ophir sensors get a high precision calibration by default with more than one wavelength.

Each thermal sensor is calibrated independently of a particular Ophir power meter with its calibration information contained in the DB15 plug. When the sensor is connected to the meter, the meter reads and interprets this information to display a calibrated reading. Each power meter is calibrated independently and has the same sensitivity as an other meter within about 2 tenths of a percent.

Unless otherwise indicated, Ophir sensors and meters should be recalibrated within 18 months after initial purchase, and then once a year after that.

Absorption of different thermal sensor absorber types

Features

Choosing a Thermal Sensor

In this short “Basics” video we review the use – and selection - of thermal sensors for measuring low, medium and high laser powers.

Sensors for Measuring Laser Power

Measuring Very High Power Laser Beams

Water Cooled Sensors: Things to Look Out For

Thermal Sensor Calibration

As the spectral sensitivity of the absorber used for the power and energy measurement is not fully linear, Ophir sensors get a high precision calibration by default with more than one wavelength.

Unless otherwise indicated, Ophir sensors and meters should be recalibrated within 18 months after initial purchase, and then once a year after that.

Absorption of different thermal sensor absorber types

Frequently Asked Questions

Must I use a particular sensor only with the meter it was ordered with?
Answer
Ophir meters and sensors are calibrated independently. Each meter has the same sensitivity as the other within about 2 tenths of a percent. Each sensor is calibrated independently of a particular meter with its calibration information contained in the DB15 plug. When the sensor is connected to the meter, the meter reads and interprets this information. Since the accuracy of our sensors is typically +/-3%, the extra 0.2% error that could come from plugging into a different meter is negligible and therefore it does not matter which calibrated meter we use with a particular calibrated sensor.

When an accuracy spec is given, what exactly is meant?
Answer
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 sensors will be within this accuracy and 99% will be within +/-4%. For further information on accuracy see calibration procedure tutorial and knowledge center.

Is there a coolant pressure specification for Ophir water-cooled sensors?

Answer

Yes. Please reference the chart below:

Minimum Flow Rates for Water-Cooled Sensors

Sensor	Recommended flow rate at full power¹	Minimum flow rate at full power¹	Absolute minimum flow rate	pressure drop across sensor (at maximum flow rate)		pressure drop across 8 meter of tubing (at maximum flow rate)
Sensor	liters/min)	(liters/min)	(liters/min)	Bar	MPa	Bar	MPa
L250W	3	3	3	0.3	0.03
L300W	3	3	3	0.3	0.03
1000W	6	3	3	0.3	0.03	0.5	0.05
L1500W	6	3.5	3	0.3	0.03	0.5	0.05
L2000W	6	3.5	3	0.6	0.06	0.5	0.05
5000W	8	5	3	0.6	0.06	0.5	0.05
6K-W-200x200	6	6	5	0.5	0.05	0.3	0.03
10K-W	8	8	3	1	0.1	0.5	0.05
15K-W	12	12	3	2	0.2	1	0.1
16K-W	12	12	3	1	0.1	0.8	0.08
30K-W	25	25	6	2	0.2	3	0.3
120K-W	60	60	30	4	0.4	3.5	0.035

You can find a lot more information about the correct use of water-cooled sensors in the article "How to use water cooled Ophir sensors", here.

Does the damage threshold depend on power level?
Answer
The damage threshold of thermal sensors 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 sensor, something which is not done by most other manufacturers. This should be taken into account when comparing specifications. The Sensor Finder takes the power level into consideration when calculating damage threshold.

How should I clean my sensor?
Answer
First, clean the absorber surface with a tissue, using Umicore #2 Substrate Cleaner, acetone or methanol. Then dry the surface with another tissue. Please note that a few absorbers (Pyro-BB, 10K-W, 15K-W, 16K-W and 30K-W) cannot be cleaned with this method. Instead, simply blow off the dust with clean air or nitrogen. Don't touch these absorbers. Also, HE sensors (such as the 30(150)A-HE-17) should not be cleaned with acetone.

Note: These suggestions are made without guarantee. The cleaning process may result in scratching or staining of the surface in some cases and may also change the calibration.

Do I need to recalibrate my instrument? How often must it be recalibrated?
Answer
Unless otherwise indicated, Ophir sensors and meters should be recalibrated within 18 months after initial purchase, and then once a year after that.

Can a laser measurement depend on the distance from the laser to the sensor?
Answer
In theory, if a beam is completely parallel and fits within the aperture of a sensor, then it should make no difference at all what the distance is. It will be the same number of photons (ignoring absorption by the air, which is negligible except in the UV below 250nm). If, nevertheless, you do see such a distance dependence, there could be one of the following effects happening:
- If you are using a thermal type power sensor, you might actually be measuring heat from the laser itself. When very close to the laser, the thermal sensor might be “feeling” the laser’s own heat. That would not, however, continue to have an effect at more than a few cm distance unless the light source is weak and the heat source is strong.
- Beam geometry – The beam may not be parallel and may be diverging. Often, the lower intensity wings of the beam have greater divergence rate than the main portion of the beam. These may be missing the sensor's aperture as the distance increases. To check that you'd need to use a profiler, or perhaps a BeamTrack PPS (Power/Position/Size) sensor.
- If you are measuring pulse energies with a diffuser-based pyroelectric sensor: Some users find that when they start with the sensor right up close to the laser and move it away, the readings drop sharply (typically by some 6%) over the first few cm. This is likely caused by multiple reflections between the diffuser and the laser device, which at the closest distance might be causing an incorrectly high reading. You should back off from the source by at least some 5cm, more if the beam is not too divergent.
Needless to say, it’s also important to be sure to have a steady setup. A sensor held by hand could easily be moved around involuntarily, which could cause partial or complete missing of the sensor’s aperture at increasing distance, particularly for an invisible beam.

How do you calculate the power and energy density of a laser beam?
Answer
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). The sensor finder will automatically calculate the power and energy density.

For the 120K-W sensor, what is the maximum power density? It is not given as such in the specification.
Answer
The spec was designed around the way such lasers are typically used. Since these lasers are normally used with focusing optics, the spec of the 120K-W does not give a maximum power density; rather, it defines the assumed focusing-lens focal length and position such that the beam will end up having a 100mm diameter at the cone, and defines the assumption of a near Gaussian beam under those conditions so we can define a baseline number. This is defined briefly in the spec, and in a bit more detail in the User Note that comes with the sensor.

Once and for all: Is DI (deionized) water good or bad for water-cooled sensors? Does it help prevent corrosion, or does it actually increase the risk?
Answer
Many factors affect the risk of corrosion forming, but the two most important are:
- the mixture of ions in the water
- the water’s pH
Our current recommendation is to use DI water – but of a neutral pH. DI water is usually slightly acidic; it can be titrated to a neutral pH, using a bit of sodium hydroxide for example. There are also commercial additives that can help prevent corrosion, for instance Optishield Plus. For a more detailed discussion, see the FAQ at https://www.ophiropt.com/laser--measurement/knowledge-center/faq/7805

You can find a lot more information about the correct use of water-cooled sensors in the article "How to use water cooled Ophir sensors", here.

The sensor I need uses water cooling. Can you recommend a water cooling system?
Answer

We don’t supply chillers, nor insist on specific models; the only important thing from our point of view is to simply keep to the requirements specified for the cooling water of the specific model of sensor, such as minimum flow rate at full power, water temperature range, and - more important than the actual water temperature - water temperature stability. The temperature of the water should not be changing by more than 1 deg/min (because changes in water temperature could cause heat flow in the sensor which would be detected as if it were laser power, and cause errors in the reading).

Our blog has a video on this subject: Water Cooled Sensors: Things to Look Out For, which discusses various issues and tips about water cooling.

To help ensure correct alignment of my beam in my 120K-W sensor, can I insert the laser head (the QBH connector) into the opening of the 120K-W “beam dump” cylinder?
Answer
We would not recommend doing that. Besides possibly affecting the correct performance of the sensor, there is a risk of potential damage to the laser if a small percentage of the beam is reflected (off the sensor’s reflective cone) back into it.

Frequently Asked Questions

Must I use a particular sensor only with the meter it was ordered with?
Answer
Ophir meters and sensors are calibrated independently. Each meter has the same sensitivity as the other within about 2 tenths of a percent. Each sensor is calibrated independently of a particular meter with its calibration information contained in the DB15 plug. When the sensor is connected to the meter, the meter reads and interprets this information. Since the accuracy of our sensors is typically +/-3%, the extra 0.2% error that could come from plugging into a different meter is negligible and therefore it does not matter which calibrated meter we use with a particular calibrated sensor.

When an accuracy spec is given, what exactly is meant?
Answer
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 sensors will be within this accuracy and 99% will be within +/-4%. For further information on accuracy see calibration procedure tutorial and knowledge center.

Is there a coolant pressure specification for Ophir water-cooled sensors?

Answer

Yes. Please reference the chart below:

Minimum Flow Rates for Water-Cooled Sensors

Sensor	Recommended flow rate at full power¹	Minimum flow rate at full power¹	Absolute minimum flow rate	pressure drop across sensor (at maximum flow rate)		pressure drop across 8 meter of tubing (at maximum flow rate)
Sensor	liters/min)	(liters/min)	(liters/min)	Bar	MPa	Bar	MPa
L250W	3	3	3	0.3	0.03
L300W	3	3	3	0.3	0.03
1000W	6	3	3	0.3	0.03	0.5	0.05
L1500W	6	3.5	3	0.3	0.03	0.5	0.05
L2000W	6	3.5	3	0.6	0.06	0.5	0.05
5000W	8	5	3	0.6	0.06	0.5	0.05
6K-W-200x200	6	6	5	0.5	0.05	0.3	0.03
10K-W	8	8	3	1	0.1	0.5	0.05
15K-W	12	12	3	2	0.2	1	0.1
16K-W	12	12	3	1	0.1	0.8	0.08
30K-W	25	25	6	2	0.2	3	0.3
120K-W	60	60	30	4	0.4	3.5	0.035

You can find a lot more information about the correct use of water-cooled sensors in the article "How to use water cooled Ophir sensors", here.

Does the damage threshold depend on power level?
Answer
The damage threshold of thermal sensors 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 sensor, something which is not done by most other manufacturers. This should be taken into account when comparing specifications. The Sensor Finder takes the power level into consideration when calculating damage threshold.

How should I clean my sensor?
Answer
First, clean the absorber surface with a tissue, using Umicore #2 Substrate Cleaner, acetone or methanol. Then dry the surface with another tissue. Please note that a few absorbers (Pyro-BB, 10K-W, 15K-W, 16K-W and 30K-W) cannot be cleaned with this method. Instead, simply blow off the dust with clean air or nitrogen. Don't touch these absorbers. Also, HE sensors (such as the 30(150)A-HE-17) should not be cleaned with acetone.

Note: These suggestions are made without guarantee. The cleaning process may result in scratching or staining of the surface in some cases and may also change the calibration.

Do I need to recalibrate my instrument? How often must it be recalibrated?
Answer
Unless otherwise indicated, Ophir sensors and meters should be recalibrated within 18 months after initial purchase, and then once a year after that.

Can a laser measurement depend on the distance from the laser to the sensor?
Answer
In theory, if a beam is completely parallel and fits within the aperture of a sensor, then it should make no difference at all what the distance is. It will be the same number of photons (ignoring absorption by the air, which is negligible except in the UV below 250nm). If, nevertheless, you do see such a distance dependence, there could be one of the following effects happening:
- If you are using a thermal type power sensor, you might actually be measuring heat from the laser itself. When very close to the laser, the thermal sensor might be “feeling” the laser’s own heat. That would not, however, continue to have an effect at more than a few cm distance unless the light source is weak and the heat source is strong.
- Beam geometry – The beam may not be parallel and may be diverging. Often, the lower intensity wings of the beam have greater divergence rate than the main portion of the beam. These may be missing the sensor's aperture as the distance increases. To check that you'd need to use a profiler, or perhaps a BeamTrack PPS (Power/Position/Size) sensor.
- If you are measuring pulse energies with a diffuser-based pyroelectric sensor: Some users find that when they start with the sensor right up close to the laser and move it away, the readings drop sharply (typically by some 6%) over the first few cm. This is likely caused by multiple reflections between the diffuser and the laser device, which at the closest distance might be causing an incorrectly high reading. You should back off from the source by at least some 5cm, more if the beam is not too divergent.
Needless to say, it’s also important to be sure to have a steady setup. A sensor held by hand could easily be moved around involuntarily, which could cause partial or complete missing of the sensor’s aperture at increasing distance, particularly for an invisible beam.

How do you calculate the power and energy density of a laser beam?
Answer
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). The sensor finder will automatically calculate the power and energy density.

For the 120K-W sensor, what is the maximum power density? It is not given as such in the specification.
Answer
The spec was designed around the way such lasers are typically used. Since these lasers are normally used with focusing optics, the spec of the 120K-W does not give a maximum power density; rather, it defines the assumed focusing-lens focal length and position such that the beam will end up having a 100mm diameter at the cone, and defines the assumption of a near Gaussian beam under those conditions so we can define a baseline number. This is defined briefly in the spec, and in a bit more detail in the User Note that comes with the sensor.

Once and for all: Is DI (deionized) water good or bad for water-cooled sensors? Does it help prevent corrosion, or does it actually increase the risk?
Answer
Many factors affect the risk of corrosion forming, but the two most important are:
- the mixture of ions in the water
- the water’s pH
Our current recommendation is to use DI water – but of a neutral pH. DI water is usually slightly acidic; it can be titrated to a neutral pH, using a bit of sodium hydroxide for example. There are also commercial additives that can help prevent corrosion, for instance Optishield Plus. For a more detailed discussion, see the FAQ at https://www.ophiropt.com/laser--measurement/knowledge-center/faq/7805

You can find a lot more information about the correct use of water-cooled sensors in the article "How to use water cooled Ophir sensors", here.

The sensor I need uses water cooling. Can you recommend a water cooling system?
Answer

We don’t supply chillers, nor insist on specific models; the only important thing from our point of view is to simply keep to the requirements specified for the cooling water of the specific model of sensor, such as minimum flow rate at full power, water temperature range, and - more important than the actual water temperature - water temperature stability. The temperature of the water should not be changing by more than 1 deg/min (because changes in water temperature could cause heat flow in the sensor which would be detected as if it were laser power, and cause errors in the reading).

Our blog has a video on this subject: Water Cooled Sensors: Things to Look Out For, which discusses various issues and tips about water cooling.

To help ensure correct alignment of my beam in my 120K-W sensor, can I insert the laser head (the QBH connector) into the opening of the 120K-W “beam dump” cylinder?
Answer
We would not recommend doing that. Besides possibly affecting the correct performance of the sensor, there is a risk of potential damage to the laser if a small percentage of the beam is reflected (off the sensor’s reflective cone) back into it.

Accessories

N Polarity Power Supply/Charger

Power Supply/Charger for Centauri, Vega, Nova II, LaserStar, Nova, EA-1, Pulsar, Quasar, 6K-W, 120K-W and fan cooled sensors.

	Compare	Description	Compatibility	Drawings, CAD & Specs	Avail.	Price
		7E05029 DC Power Supply / Charger, N Polarity	UNIVERSAL		Contact Us	$52

Extended Warranty for Sensor

Customers that purchase the above items also consider the following items. Ophir-Spiricon meters and sensors include a standard manufacturers warranty for one year. Add a one year Extended Warranty to your meter or sensor, which includes one recalibration.