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csown42@gmail.com

206.288.3230

Curriculum Vitae



 

 

Turn-key Design Solutions

Scientific Instrumentation

Consumer Products

 

Chris has had over a decade experience delivering successful consumer electronics products to market. In 2003, Chris founded Ack! Industries to deliver elegant cutting-edge digital bridge solutions for the high-end audio market.

He also has over 15 years experience in scientific instrumentation design and manufacture. Aside from assisting clients in the startup and academic spheres on challenging projects in instrumentation and R&D in the physical sciences, he has also worked at Nion, the company that invented breakthrough adaptive corrective optics for scanning transmission electron microscopes (STEMs) that overcame barriers that had previously limited the resolving power of electron microscopes for decades. Chris was responsible for design, testing, and manufacture of several subsystems of the Nion UltraSTEM, the highest-performance STEM in the world.

From this immense breadth of experience, Clients can expect innovative and high-performance results for projects varying from one-off prototypes to products targeted for full production.


 

Turn-Key Design Solutions

 

Precession Box

Chris designed and built this third-generation precession device and delivered it to three University labs around the US.

Precession Device Users Manual

Electron Beam Precession Instruments - Chris has provided computer-controlled device retrofits onto an existing transmission electron microscope to produce conical illumination electron beam scans. Data from this machine significantly improves the quality of diffraction data obtained. Whereas diffraction data is corrupted by dynamical diffraction in conventional electron microscopes, the data improved by beam precession can be used for precise solution of unknown atomic structures in small volumes of 100 nm3 or less.

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Examples of conventional and precession electron diffraction patterns for a 42 nm thick (Ga,In)2SnO4 sample. Spot radii are proportional to intensity. There is a striking difference between the two patterns. In the right-hand pattern, the dynamical diffraction is substantially reduced, and the precessed intensities can be directly used for solving the structure without any additional a priori information.

 


Scientific Instrumentation

Ultra-high-speed data acquisition and motion control - Chris developed bleeding-edge systems for high-speed atomic-resolution imaging of DNA molecules. His designs allowed an atomic-resolution STEM to operate two to three orders of magnitude faster, and enabled the first nucleotide sequence data to be produced from individual ssDNA strands. He is continuing this work developing new dedicated systems for ultra-high-speed imaging of macromolecules. The image below is a short segment of linearized DNA that is hundreds of nucleotide bases long that was directly imaged in this automated system.

Osmium-labeled DNA

 

Scanning and Acquisition Unit - Chris contributed to the design and manufacture of this beam scanning and data acquisition system. The most complex piece of electronics in the UltraSTEM, the acquisition unit generates low noise scanning signals and simultaneously digitizes signals from up to four detectors. It is unique in that the scan generator, magnification unit, and data acquisition are all integrated into a single unit.

Chris wrote the firmware for the microcontroller and gate arrays on the mainboard and daughterboards, and wrote the software that controls scanning and acquisition. (Languages: VHDL, C, and C++)

Acquisition Unit

Atomically-precise Sample Stage - This nanoprecision manipulator is capable of accepting a cartridge loaded with a 3 mm sample and moving it in six axes with sub-nanometer precision. The ultra-stable stage is temperature-compensated with drift limited to less than one Å in ten minutes, and can move reproducibly in its X/Y/Z axes in 5 Å increments with essentially zero local hysteresis. The control software features eucentric tilting compensation, the ability to tilt the sample by several degrees while keeping the region of interest imaged by the microscope the same.

Chris contributed several key elements to the design and also performed the majority of design checking, and also built and characterized the first prototype. Chris designed and wrote the high-level software that controls the stage and co-wrote the software that controls the low-level mechanics. (Languages: C++ and C#)

 

Video of the stage moving in x, y squares in decreasing increments (2 nm to 0.25 nm). The stage shows no evidence of local hysteresis or backlash, which would normally manifest as rotation of the square with each reduction. (Requires Adobe Flash player. Click expand for fullscreen mode.)

 

Sample Stage

Sample stage mechanics with objective lens polepiece removed for clarity. The double-tilt cartridge is inserted into a temperature-compensated ring assembly that is suspended on ceramic ball bearings. Microstepping motors drive the stage from outside the objective lens module through ultralow-backlash mechanical linkages.

Sample exchange - The Nion sample exchange stores up to five sample cartridges in a motorized magazine. Samples are introduced at air, pumped down to 10-8 torr, and inserted into the column by automated control software.

Chris contributed elements of the design, such as the magazine elevator assembly and arrangement of position sensor systems, and he performed the design checking. He produced the initial software specification and co-wrote the software that controls the low-level mechanics.

Other subsystems - Chris designed the Nion USB Display used for manual control of the microscope and Nion Beam Blanker, and wrote the software for controlling the photomultiplier detector boards.

Sample Exchange

Consumer Products

dAck! - This digital-to-analog converter design has two unique features: it is non-oversampling and uses rechargeable batteries to reduce the noise floor below 110 dB. The non-oversampling design circumvents traditional analog brickwall filters that cause harsh-sounding amplitude and phase artifacts in the audible band, and avoids oversampling artifacts that filter into the audible band through intermodulation effects. As a result, the impulse response is ideal, imparting excellent fidelity to percussive instruments, and the all-important midrange is tonally very pure.

The design may be used with software-based oversampling algorithms to produce very high-quality sound with Nyquist frequency much higher than the usual 22.05KHz for digital audio. In 2005, Ack! Industries released the dAck! 2.0, a more refined version of the dAck! with a more stable buffered DAC reference, transformer-coupled digital input, and tighter PLL loop.

dAck! 2.0 Users Manual

dAck!

Ack Logo

dAck! inside

Melody Nelson - Chris designed this two-channel single-ended tube preamplifier for high-fidelity audio reproduction with five switchable inputs and two buffered switchable outputs. A dual triode vacuum tube is used for each channel in two gain stages, each followed by a high impedance current source that biases the stage into high class A operation.

The preamplifier is a two-box design with outboard power supply connected by an umbilical. Each channel has independent power supplies and gain stages, and the filaments are DC-heated. Design elements eliminate crosstalk and avoid coupling 60Hz into the gain circuits. Attenuation is provided by a 23-position discrete shunted stepped attenuator, which presents the same nominal 100K input impedance regardless of attenuation level.

Melody Nelson

 

   
 
     
Christopher S Own - 2012