LASER ABLATION SYSTEM FOR U-PB GEOCHRONOLOGY APPLICATIONS

LASER ABLATION SYSTEM FOR U-PB GEOCHRONOLOGY APPLICATIONS Project Description :The Unversity of Ottawa is pleased to invite qualified proponents to submit a proposal for a Laser Ablation System that will be used to acquire U-Pb isotopic data on zircon and other minerals in order to provide precise and quality geochronological constraints on rocks of various ages. They system must consist of an excimer (λ= 193 nm) laser ablation system and be equipped with a dual-volume sample cell, that can hold a variety of geological matrials (i.e. thin sections and grain mounts). Mandatory Requirements: LASER ABLATION SYSTEM: 1.1 Laser ablation system must be a Class 1 laser with a 193 nm wavelength excimer laser. The system must be fully interlocked with a fully enclosed beam path 1.2 Laser spot sizes must be available in a size range from 2 microns to 100 microns diameter, or square, as standard. 1.3 Must allow for repetition rate at least up to 100Hz 1.4 The system must be capable of delivering

up to at least 12 J/cm2 on-sample fluence 1.5 The pulse width of the laser must be 10 ns or less 1.6 The laser must have a maximum output energy of at least 10 mJ/pulse at 193 nm 1.7 The laser must be warrantied to perform with an energy stability of better than 2% (SD) at pulse energies > 6 mJ 1.8 The system must be housed in a self-contained platform. All the necessary laser gas cylinders, vacuum pump and halogen filter must be contained in a vented gas cabinet 1.9 The system control software must allow the user to specify the fluence required on the sample in 0.1 J/cm2 steps 1.10 The system must produce a laser beam with a sufficient level of lateral energy homogeneity to produce clean, flat-bottomed craters of repeatable shape and size for depth profiling of a wide variety of opaque and transparent materials (as demonstrated by Scanning Electron Microprobe – SEM) 1.11 Laser attenuators must be capable, via software control, of varying the laser energy delivered to the sample 1.12 The system must not exceed 200 cm x 200 cm x 200 cm (L x W x H) in dimension 1.13 The platform must include castor wheels so that the system can be moved as necessary VIEWING OPTICS: 2.1 The software must provide real-time image of the sample in transmitted (plane and polarized light) and reflected illumination 2.2 System must provide motorized zoom optics capable of resolving micron sized sample features in the real-time video feed 2.3 The control software must feature both a live video display from the viewing microscope as well as a resizable overview showing any part of the holder that is of interest STAGE AND SAMPLE CELL: 3.1 The minimum cell dimension must be 10 cm x 10 cm 3.2 The system must include a minimum of two (2) mass flow controllers that are integrated within the control software to allow for He and N2 into the cell 3.3 It must be possible to control the gas flows using the laser ablation system control software 3.4 The sample cell must be provided with sample holders / drawers / trays as standard to accommodate a range of samples, including round mounts and thin sections 3.5 The system must be equipped with a fully motorized XYZ stage that is controlled by the computer either automatically during a sequence or through manual input 3.6 The system must include a “Squid-type” device to smooth transient LA-ICP-MS signals COMPUTER AND CONTROL SOFTWARE: 4.1 The system must be supplied with a computer that interfaces and controls the laser ablation system. 4.2 The system control software must allow the users to simply specify point coordinates of analytical targets from either the live video display or the resizable overview. 4.3 A range of input options must support the rapid designation of other sample targets, including: paths, points along a line or in an area, and parallel paths within an area. All of these options must be accessible and editable in a sequence parameters panel. ICP-MS INTEGRATION: 5.1 Must be commonly used for U-Pb geochronology of zircon by current LA-ICPMS instrument 5.2 The proposed equipment must be functional, successfully tested and field-proven, as well as commercially available. Prototypes will not be accepted. 5.3 System must be compatible with Agilent and Thermo Scientific ICP-MS instruments used for automatic data acquisition triggering. INSTALLATION AND WARRANTY: