What does her job involve?

As a mechanical technologist, Felicia Ochoa does whatever it takes to complete a project. And what are her projects? Helping to build beamlines at the ALS so scientists can use bright x-rays to conduct experiments in everything from physics to biology. To construct a beamline or an entire experimental chamber, her supervisor breaks the project up, assigning various people to different jobs depending on their experience and specialty. Depending on the project, Felicia Ochoa might start with a mechanical drawing of a needed part, assemble the raw materials, and then machine them with the mills and lathes.

All parts must be cleaned with the ultrasonic machine in the clean sink before being used because the accelerator and beamlines are all under ultra-high vacuum. Recently, in less than a day and a half, she made, cleaned, and assembled specialized, one-inch clamps needed for a monitor which checks the position of a beam of x rays (or photons) as it travels down a beamline. Another important aspect of her job is problem solving, such as looking for any leaks in the vacuum when new parts are added to the storage ring or to a beamline. Finally, as a member of a busy team, Felicia can often be found working with other technologists and specialists to have parts welded together, hoisted up, and electroplated.

What is she doing now?

Right now, Felicia is working on a project called SPEM, located at Beamline 7.0 in the ALS. SPEM is a scanning microscope, which is both a microscope and a soft x-ray spectroscopy facility (which means it can identify the substance it is viewing). She and other technicians are working on the experimental chamber. Following a plan supplied by an engineer, she assembles pre-fabricated parts including tubes, pumps, valves, stands, struts, a complicated sample manipulator, and the experiment endstation. To do these jobs, she needs various hand tools like wrenches, screwdrivers, and basically whatever else it takes to get the job done. To avoid fingerprints and dust inside the chamber, she wears gloves, wipes parts down with ethyl alcohol, and wraps them in aluminum foil.

What are the highs and lows of her job?

According to Felicia, one of the most challenging parts about being a technologist is keeping the parts clean enough for ultra-high vacuum. Organic matter (like bugs), dust particles, and even fingerprints are unacceptable. In the vacuum chamber, contamination vaporizes, lowering the pressure and making it impossible to maintain high vacuum---and we need ultra-high vacuum so that the electron beam and x-ray beams can travel unhindered through the vacuum chamber. Even molecules of water can disrupt the vacuum. Sometimes gas molecules can coat and, as a result, interfere with the precision of the mirrors and optics which guide the beam of light down the beamline to the experiment endstation.

For Felicia, the best part about being a technician is the sense of accomplishment that comes with successfully completing a project. Sometimes her sense of accomplishment is bolstered by her creative input into solving a problem in a unique way. Once she needed to make a small, 1-3/8" diameter screen to fit into a "T"-shaped piece of metal. The screen, made of extremely sheer metal, would be used to draw electrons passing through it to the "T", and then to ground. The hard part was figuring out how to stretch the fine mesh and get it to stay attached to the "T". So, on her way home from work one day, Felicia went to a sewing shop and bought some fine material and an embroidery hoop. By practicing stretching pieces of the material and fitting them together, she figured out how she could use the spot welder to attach the mesh screen to the "T". And it worked! See the screen, the hoop, and the end result.

What is a typical day at the ALS like for her?

Typically, Felicia receives an assignment from her supervisors to build a particular piece of equipment. It's up to Felicia to do what it takes to get the job done. For example, she can be assigned to assemble a diagnostic for a beamline. A diagnostic is an instrument that checks the position and intensity of a photon or x-ray beam as it travels down a beamline. It does this by taking a "picture" of the beam using a camera pointed at a copper-coated paddle which has been lowered into the beamline. Take a look at a diagnostic before and after it is placed in a beamline.

To build the diagnostic, Felicia is supplied with the pre-fabricated parts which must first go to the plating shop where they are cleaned with a highly caustic soap solution, rinsed, dipped in an acid solution, rinsed again, and electro-polished. Since even the fatty oil deposits from fingerprints will dirty the parts, they must be carefully transported to the welding shop. Then, to leak test the welded parts, Felicia Ochoa designs a fixture that she can use in the leak detector. The leak detector is like a vacuum that is hooked up to a helium monitor. When Felicia sprays helium around the welded joints, the helium monitor detects any helium molecules that may slip inside, thus indicating a leak. After the diagnostic is assembled, it is used with other parts to monitor the position of a photon beam in the beamline.