Applied Photonics LIBS-6 User manual

Modular
Laser-Induced Breakdown Spectroscopy (LIBS)
System
User’s Manual for Example Configuration 1
June 2022
Applied Photonics Ltd
Unit 8 Carleton Business Park, Skipton, North Yorkshire BD23 2DE, United Kingdom
Tel [phone] Fax [phone] Web: www.appliedphotonics.co.uk
© 1998 - 2022 Applied Photonics Ltd

© 1998 - 2022 Applied Photonics Ltd Page 2 of 41
Contents Page
1. Introduction 3
2. Safety 3
2.1 Laser radiation 3
2.2 Note on the laser safety window material used in the modular sample chambers 6
2.3 Electrical 6
3. General description 7
3.1 Overview 7
3.2 Laser beam expander and plasma light collection optics 11
3.3 Right-angle Mirror Module 12
3.4 Attaching the LIBS-6 / LIBS-8 module to a laser 12
3.4.1 Adaptor Platforms 12
3.4.2 Litron Nano SG 150-10 (1064 nm) laser 13
3.4.3 Litron Nano LG 300-10 (1064 nm) laser 14
3.4.4 Configuration options 14
3.5 Modular sample chambers 16
3.5.1 Overview 16
3.5.2 XYZ-750 computer-controlled sample chamber 17
3.5.3 SC-2L modular sample chamber 18
3.6 SpectroModule-6 and SpectroModule-8 multi-channel LIBS spectrometers 20
3.7 Fibre-optic connections 22
3.8 Electrical connections 24
3.9 Imaging camera and associated components 25
3.10 Gas purge feature and air pump 27
3.11 LIBSoft software 28
3.12 System computer specifications 28
3.13 Setting the position of the acrylic nozzle aperture 29
3.14 Adjusting and setting the laser beam focus 30
3.15 Using an energy meter to measure the laser pulse energy 31
3.16 Important note on back-reflections of laser radiation 32
4. Assembly of the LIBS equipment 34
4.1 Introduction 34
4.2 Step-by-Step guide to configuring the LIBS equipment 34
5. Operating procedure 37
5.1 Introduction 37
5.2 Step-by-Step guide to operating the LIBS equipment 37
6. Shut-down procedure 39
7. Operating the LIBS equipment in “open beam” configuration 39
8. Maintenance and inspection 40
9. Shipping and storage 40
10. Trouble-shooting / fault finding 40

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1 Introduction
The modular Laser-Induced Breakdown Spectroscopy (LIBS) system described in this User’s Manual is
designed to be a highly versatile product for use by research scientists, application engineers and OEMs.
Essentially a “LIBS system building block”, the LIBS-6 and LIBS-8 modules may be used together with a
variety of Q-switched Nd:YAG lasers and optical spectrometers to form a customised, modular LIBS
system tailored to suit the requirements of a specific application or experimental research project. The
LIBS modules remove the need for the research scientist or application engineer to design and construct
their own laser focussing optics and plasma light collection optics by combining these features into a
compact, integrated and easy to use device. An optional imaging kit may be added to the LIBS module,
increasing further its functionality and versatility.
The modular LIBS system described in this User’s Manual comprises the following main components: a
LIBS-6 module fitted with an optional imaging camera (IMG-HR), an AP-Nano adaptor platform, a
Litron Nano SG 150-10 laser, a SpectroModule-6 multi-channel LIBS spectrometer, an SC-2L modular
sample chamber and a computer running LIBSoft software. In some sections of this User’s Manual, the
following components and devices are also described: LIBS-8 module, SpectroModule-8 six-channel
LIBS spectrometer, Litron Nano LG 300-10 laser, an XYZ-750 modular sample chamber and a dual-
camera imaging system (IMG-HR-2).
This User’s Manual provides the necessary information needed to configure the LIBS equipment and how
to operate the equipment safely. It is assumed that the user is familiar with the safety issues arising from
the use of high-power lasers and will have preferably been trained in the safe use of high-power (Class 4)
laser products.
2 Safety
2.1 Laser radiation
The modular LIBS system utilises a high-power Q-switched Nd:YAG laser (Class 4) and so it is
imperative the equipment is operated only by suitably trained and experienced persons who are fully
aware of the hazards inherent to this type of high-power laser equipment. It is imperative also that, prior
to using the equipment, an appropriate risk assessment is conducted in such a way as to take account of
the proposed use of the equipment, the environment in which the equipment is to be operated, and how its
use may affect people who are not directly involved with the use of the equipment.
Example of a laser warning product label
The modular LIBS system is designed to meet the laser safety requirements of the relevant European
standards (BS EN 60825) and USA standards (ANSI Z136.1). Although the modular LIBS system is
supplied with a sample chamber which provides adequate containment of the laser radiation to Class 1
Accessible Emission Limits, it is possible for the user to operate the LIBS equipment without the sample
chamber (i.e. operation in “open beam” mode as may be required for certain types of experiment).
Accordingly, it is necessary to consider the modular LIBS system to be a Class 4 Laser Product and so,
by definition, the equipment poses a risk of personal injury (eye, skin injury) and poses a fire risk. As

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with all Class 4 laser products, appropriate safety precautions must be taken as identified via a suitable
risk assessment conducted by the user in consultation with a suitably qualified and experienced Laser
Safety Officer.
The most significant hazard relating to exposure of personnel to the laser radiation is eye injury since
direct or scattered laser radiation produced by the equipment can cause serious and permanent injury to
the eyes including blindness - such injury may be instantaneous. Precautions must be taken to avoid
exposure of personnel to hazardous levels of laser radiation. Such precautions may include the setting up
of a temporary or permanent laser controlled area (e.g. a laser laboratory). Other measures may also be
necessary, as determined by appropriate and thorough assessment of the risks (i.e. a risk assessment)
conducted by the personnel responsible for the safe use of the laser equipment. Consult the User’s
Manual supplied with the laser for further guidance on the safe use of the laser.
The door of the sample chamber is equipped with a dual electrical interlock switch which is designed to
prevent activation of the laser unless the door is fully closed. The door interlock switch is electrically
connected to the “Interlock In/Out” port on the LIBS module via the 9-pin connector located directly
above the laser aperture. The “Interlock In/Out” port connects with the SpectroModule-8 (using the
supplied lead) which in turn is connected to the interlock circuits of the laser power supply. The laser
safety interface between the SpectroModule-8 and the laser power supply depends on the make and model
of laser being used. Throughout this User’s Manual, it is assumed that a Litron NANO SG 150-10 laser
and associated power supply is used, together with an SC-2L 3-axis manually-controlled sample chamber.
Removal of the sample chamber from the LIBS-6 module, or disconnection of the Interlock In/Out lead,
will also activate the interlock (i.e. prevent activation of the laser). The SpectroModule-6 multi-channel
LIBS spectrometer is equipped with an Interlock Override facility (a keyswitch) which allows the
interlock to be disabled so that the LIBS system may be used without a sample chamber (i.e. “open beam”
mode). In view of this, the modular LIBS system must be categorised as a Class 4 laser product since,
by design, the product may be used in such a way that the laser beam is not contained (i.e. “open beam”
mode of operation).If, however, the sample chamber is correctly fitted to the LIBS-6 module and the
Interlock Override keyswitch is switched off and the key removed, then the laser radiation is adequately
contained to Class 1 Accessible Emission Limits by the design of the hardware.
IMPORTANT
•READ and UNDERSTAND both this User’s Manual and the instructions provided by the
manufacturer of the laser before operating the LIBS equipment.
•ENSURE that an appropriate risk assessment has been conducted to establish whether or not the
laser safety windows fitted to the modular sample chambers provide adequate protection against
exposure to laser radiation for the specific laser you intend to use with the LIBS equipment.
For advice on this matter, consult your Laser Safety Officer and/or Applied Photonics Ltd.

© 1998 - 2022 Applied Photonics Ltd Page 5 of 41
•ONLY suitably qualified and authorised persons should activate the Interlock Override keyswitch.
The key should be removed from the keyswitch and held by the Laser Safety Officer when this
feature is not required.
•ALWAYS use appropriate laser safety protective eyewear when operating the LIBS equipment in
“open-beam” configuration –you should seek advice from your Laser Safety Officer on this
matter.
•ALWAYS switch the laser off when not in use and remove the key from the keyswitch of the laser
power supply to prevent unauthorised activation.
•ALWAYS thoroughly inspect the LIBS equipment for damage prior to use. Particular attention
should be given to the laser safety windows and the laser safety interlock system, which should be
tested each time the equipment is used.
•NEVER allow unauthorised and/or untrained persons operate the LIBS equipment.
•NEVER operate the LIBS equipment in areas where explosive gas mixtures may be present.
•NEVER operate the LIBS equipment with any access cover, panel, or protective window
removed.
•NEVER place inside the sample chamber flammable liquids or any other material which may give
rise to flammable / explosive gas mixtures. Activation of the laser under these conditions could
result in an explosion leading to severe personal injury and/or fire hazard. Remember that the
laser-induced plasma is a source of ignition.
•NEVER point the LIBS laser beam at a person (even with laser switched off), especially towards
the eyes, even if the person is wearing laser safety eyewear. The laser should be considered
“active” unless the laser power supply is fully deactivated.
•NOTE that the transparent acrylic nozzle aperture of the LIBS-6 or LIBS-8 module does not
provide any protection to the user against exposure to direct or scattered laser radiation. The
function of the nozzle aperture is described later in this User’s Manual.
Image of LIBS-6 module showing location of laser warning
indicator lights, laser aperture and warning label
Laser warning
indicator lights
Laser aperture
warning label
Laser aperture
Transparent nozzle
aperture
Electrical connection to
SpectroModule-6 (-8) or
Interlock Interface Unit
Camera setup
joystick
LED
intensity
Electrical
connection to
sample chamber

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2.2 Note on the laser safety window material used in the modular sample chambers
The laser safety window material fitted to the sample chamber is rated as follows:
Laser
Wavelength
(nm)
USA Standard
ANSI Z 136.1 –2014
UK & European Standard
BS EN 207:2017
Optical
Density
Protection Level R
(Q-switched laser)
1064
OD 6+
L6
355
OD 5+
L5
266
OD 5+
L5
R L6 at 1064 nm indicates a protection level of maximum spectral transmittance of 10-6 at 1064 nm for a
pulsed laser of pulse length 10-9 –10-7 seconds (i.e. a Q-switched laser).
The laser safety windows used in Applied Photonics Ltd’s range of modular sample chambers provide
adequate protection against scattered laser light of wavelength 1064 nm, 355 nm and 266 nm such that
Class 1 Accessible Emission Limits are met if the sample chamber is used correctly and laser pulse
energies are not excessively high (i.e. typically less than 300 mJ with a 5 - 10 ns pulse length). Note that
the protective windows are NOT suitable for use with a 532 nm laser. Given that the LIBS-6 and LIBS-8
modules may be used with a variety of lasers, it is the responsibility of the user to conduct a risk
assessment to establish whether or not the laser safety windows provide adequate protection for the
particular laser being used. If in any doubt, you should consult your Laser Safety Officer and/or Applied
Photonics Ltd for advice on this matter.
Warning –the Applied Photonics Ltd modular sample chambers are designed specifically for use
with our LIBS-6 / LIBS-8 integrated LIBS modules and our LIBSCAN range of products and
should not be used with any other laser device or product. If in doubt, seek advice from the
manufacturer, Applied Photonics Ltd.
2.3 Electrical
The LIBS-6 and LIBS-8 integrated LIBS modules, the SpectroModule-6 / SpectroModule-8 multi-
channel LIBS spectrometer and the XYZ-750 modular sample chamber contain electrical circuits
operating at 12 VDC at a maximum current of 5 Amps. Accordingly, they pose no electric shock risk.
The laser head and associated power supply, however, contain electrical circuits operating at potentially
lethal voltage and current levels. Consult the manufacturer’s User Manual supplied with the laser for
further guidance on the safe use and routine maintenance of the laser.

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3 General description
3.1 Overview
The modular LIBS system used in Example Configuration 1 consists of the following main components:
•LIBS-6 module (1064 nm) Qty 1
•Right-angle mirror module (1064 nm) Qty 1
•Adaptor Platform (AP-Nano) Qty 1
•Litron Nano SG 150-10 laser (1064 nm) Qty 1
•SpectroModule-6 multi-channel LIBS spectrometer Qty 1
•SC-2L manually-controlled sample chamber Qty 1
•Imaging kit IMG-HR (single camera) Qty 1
•LIBSoft software Qty 1
In addition to the above components, for completeness this User’s Manual includes information on
selected other components such as a LIBS-8 module, a SpectroModule-8 spectrometer, an XYZ-750
computer-controlled sample chamber and a dual-camera imaging system (IMG-HR-2).

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The main components of the LIBS-6 and LIBS-8 integrated LIBS module are illustrated in the following
figures. The LIBS-8 module is essentially identical to the LIBS-6 module except that it has eight plasma
light collection channels rather than six.

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The LIBS modules include the following features:
•Plasma light collection lens array (six or eight channels) having a relatively large depth-of-field to
allow efficient light collection even when the plasma position varies by approximately ±3 mm
along the optic axis of laser beam.
•3-lens laser beam expander with adjustable focus (adjustment of focal plane made by rotating the
brass beam expander lens holder via the cut-way in the laser beam tube –adjustment range of
approx. 14 mm).
•Adjustable nozzle aperture which provides a convenient means of setting the distance to the
sample surface (adjustment range of approx. 14 mm). The nozzle aperture may be removed if this
feature is not required.
•Gas-purge port (accepts 4 mm flexible nylon tube) which may be used to feed inert gas (e.g.
argon, helium, nitrogen) to the sample surface. To ensure purge gas is directed to the sample, it is
necessary to fit the nozzle aperture.
•Optional miniature CMOS colour video camera with array of dimmable high-brightness white
LEDs for illuminating sample surface.
•Laser safety interlock with keyswitch operated override facility (via the SpectroModule-6 or
SpectroModule-8 multi-channel LIBS spectrometer or an Interlock Interface Unit if an alternative
spectrometer is used).
•Compatible with the Applied Photonics Ltd (APL) range of modular sample chambers.
Laser
warning
light
Transparent
nozzle
aperture
Plasma light
collection
lens holder
Threaded
ring
Front
bulkhead
Camera
housing
High-
intensity
LEDs
Optics
array
Gas-purge
port
Electrical connection
(to sample chamber)
High-intensity
LED dimmer
control
Laser
interlock
connection
Tie-bar
Laser beam tube
Lock
screw
Fibre-optic
cable
Beam
expander
Rear
bulkhead
Electronics enclosure
Cut-away to allow adjustment
of laser focus

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Front view of LIBS-8 module showing plasma light collection lens array,
CMOS 2.5 MP camera, LED lights, laser aperture and gas purge outlet
Front view of LIBS-6 module showing plasma light collection lens array,
CMOS 2.5 MP camera, LED lights, laser aperture and gas purge outlet
Miniature CMOS
2.5 MP camera
(optional feature)
Two high-brightness white
LED lights
(optional feature as part of
the IMG-HR kit)
Circular array of eight lens
holders –used to collect
plasma light. The purple lens
holder is for collection of
Deep-UV, the blue lens
holders are for collection of
UV-VIS while the red lens
holders are for collection of
VIS-NIR.
Laser warning
indicator lights
Electrical connection
to sample chamber
Laser beam expander
and output aperture
Grub screw for locking
aperture nozzle (do not
over-tighten)
Gas purge outlet
Four high-brightness white
LED lights
(optional feature as part of
the IMG-HR kit)
Circular array of six lens
holders –used to collect
plasma light. The purple lens
holder is for collection of
Deep-UV, the blue lens
holders are for collection of
UV-VIS while the red lens
holders are for collection of
VIS-NIR.
Gas purge outlet