EBSP (Electron Backscatter Diffraction Pattern) Detector / Electronics
The Department of Geology and Geophysics requires a state-of-the-art CCD (charge coupled device) detector and digital electronics system for advanced backscattered electron orientation imaging and analysis to be interfaced to a Windows based Pentium PC computer system. This CCD camera system will be mechanically interfaced to a new SEM (scanning electron microscope) by the vendor or UC Berkeley. The minimum specifications of the CCD camera system and associated electronics are described in this document.
Please quote the following items separately :
1.) CCD camera (please quote both a 512 x 512 and a 1024 x 1024 system)
2.) Electronics and software
3.) Microscope mechanical interface vacuum flange and motorized slide (optional)
Although the CCD camera and electronics and software should work together and be perfectly compatible, we ask that they be quoted separately for budgetary purposes. Quotation of the microscope mechanical interface is optional. UCB can construct these components using our internal facilities. Drawings of the suggested microscope mechanical interface configuration are attached for reference purposes only.
The hardware and software shall meet all specifications prior to delivery.
Installation and Training :
The hardware and software installation and training shall be performed on site by the vendor with the participation of qualified UC Berkeley personnel working under the direction of the vendor.
The acceptance of the camera system, electronics and software is contingent upon satisfactory demonstration of all specified features, requirements and functions in this document as verified by qualified UC Berkeley personnel.
System Specifications :
1. CCD Camera
a. CCD Chip
- Full frame transfer low noise CCD for simultaneous frame readout and image acquisition for shutterless operation. The essential specification is an active imaging area of at least 12 X 12 mm square on the CCD chip. The camera should be supplied fully assembled and ready for mounting on the vacuum and mechanical interface flange (see attached drawings).
- pixel size : >12 um (e.g., Thomson THX7887A)
- number of image elements : 1024 X 1024 pixels
- number of memory elements : 1024 X 1024 pixels
- imaging area : at least 12 mm square
- full well depth : > 200,000 e- per pixel
- readout noise : < 30 e- per pixel
- frame transfer speed : < 0.05 sec.
- thermoelectric cooling device (peltier) , recirculating water cooled heat sink bonded to CCD chip, operating temperature -40 to -25 degrees C
- the CCD chip shall contain no defective rows or columns and no more than 150 "bad" pixels in the image area
- hermetically sealed camera housing for electronic data and control lines, water cooling lines and vacuum fitting for CCD housing pumpout
- To reduce strain on the CCD and to prevent delamination from the fiber optic light pipe, the CCD chip mount shall utilize a "floating head" design that allows the epoxy bonded CCD chip to move along with the fiber optic through repeated thermal cycling.
b. Fiber Optics Light Pipe
- 8-10 inch long 1:1 (no taper) zero or low shear fiber optic light pipe with protective high strength metal housing with an o-ring seal to the metal housing for microscope high vacuum interface integrity. Exact length will be specified at the time the order is placed.
- This fiber optic light pipe is to be permanently bonded to the CCD chip using a suitable epoxy. The active imaging area of the fiber optic should completely cover the CCD image area so that all CCD pixels are usable.
c. Phosphor Coated Fiber Optic Faceplate (1 faceplate installed and 2 spare are required)
- The fiber optic faceplate should be of the same material as the fiber optic light pipe and attached to the front of the fiber optic using optical grease and held in place using a metal cap that will provide protection to the edges of the fiber optic faceplate. and ensure a "bubble free" grease to glass interface.
- The protective metal cap should provide minimal relief above the phosphor coating for protection, but in order that the sample can approach the phosphor surface as closely as possible, this distance should be no more than 1 to 2 mm. The lower edge of the protective cap must be relieved at a 45 degree angle to allow the sample to approach as closely as possible.
- electron to light phosphor (P-20 red or equivalent optimized for 8 - 10 KeV electrons and CCD response curve) to be deposited on fiber optic light pipe for easy replacement or interchange of the phosphor. This may be contracted out to a specialist such as Grant Scientific (contact John Donovan for details).
- phosphor coated with a transparent conductive coating or other technique (e.g. Indium-Tin Oxide or 400 angstroms Al metal or proprietary method) sufficiently thin to pass 99% of 8 KeV electrons and grounded to the CCD housing to eliminate charging effects from the electron beam. This may be contracted out to a specialist such as Grant Scientific (contact John Donovan for details).
2. Electronics and Software
- Interface : PC PCI or SCSI interface card
- ADC : 14 bits minimum (>4095 gray levels)
- readout speed : 2 Mpixel per second (minimum)
- readout time (not including frame transfer) : < 1.0 sec. without binning
- < 0.5 sec. with 2X2 binning
- Software selectable horizontal and vertical camera binning. Binning can be adjusted between 1 and 16 pixels independently in each direction. Hardware timer gated (not PC system controlled) integration time from 0.1 to 1000 sec with better than .1% accuracy.
- Windows 95 32 bit driver, VBX or DLL (dynamic link library), with source code and documentation including code examples for interfacing to the driver or DLL from Visual Basic and C
- An application or function call must be provided for continuous "fast" image display using a "bitblt" type function to allow the image to be visible during microscope calibration procedures
- Required software functions:
- - Initialization of Parameters (count time, binning, etc)
- - Start Integration
- - Integration Status (polled status)
- - Get Image data (to passed 16 bit integer array)
- - Stop Integration (abort)
3. Optional Vacuum Interface and Mechanical Adjustment System (see attached diagram for suggested configuration).
- SEM for mechanical interfacing : Leo S430, with a fiber optic housing maximum diameter at input of < 3.0 cm
- a vacuum rated bellows of approx. 2" or less diameter or a sliding dual o-ring vacuum feed through seal in the mounting flange to maintain high vacuum integrity of the SEM, both when the fiber optic housing is stationary and during adjustment of the fiber optic housing.
- a precision mechanism must provide a means for mechanically moving the detector relative to the SEM vacuum port to adjust the sample to detector distance while under vacuum, and provide an adjustment range of at least 6 cm (e.g. motorized worm drive, rack and pinion, threaded external adjustment nut on housing, etc.). Whatever method is chosen, it must allow an easy adjustment by the user for the detector to sample distance and yet provide a rigid and vibration free mounting for acquisition of extended integration times. The anticipated vacuum force load on the fiber optic-bellows assembly will be approx. 20 - 40 lb. depending on the fiber optic housing diameter.
- the mounting flange with vacuum feed through and mechanical adjustment must fit in the existing microscope port (to be specified at a later time) without modification and provide an optimum sample to detector geometry for EBSP acquisition.
- the optimum microscope detector geometry is defined as follows (for reference purposes only):
- detector axis should be mounted at an angle of at least 90 degrees to 105 degrees to the beam vertical axis. In other words, the access port axis must be in the horizontal plane or ideally slightly below (0 to 15 degrees below horizontal)
- detector must have normal (90 degrees) line of sight to beam impact at high sample tilt (70-80 degrees)
- axis of detector insertion mechanism and motion must intersect beam impact at high sample tilt (70-80 degrees)
- the mounting mechanism must be removable from the fiber optic housing and CCD camera housing for possible SEM upgrade or modifications to the access port mounting flange
Suggested price for the CCD camera, fiber optics and electronics and software is approximately $30K (not including the vacuum and mechanical interfacing costs). Delivery of all system components must be within 90-120 days after the purchase order has been received by the vendor. Please contact us if you have any questions or concerns regarding the specifications.
Please contact :
John Donovan (510) 642-5459
Rudy Wenk (510) 642-7431
George Johnson (510) 642-3371
(510) 643-9980 (FAX)
Department of Geology and Geophysics
Department of Mechanical Engineering
University of California
Berkeley, CA 94720-4767