RARAF Microbeam Blog

Microbeam Training Course

2010-12-03T16:06:00.001-05:00

We have initiated a two-day course on charged particle microbeams to be presented annually or semi-annually, depending on demand. The first course will be given April 14-15, 2011. The course is free and is aimed at graduate students, post-docs and researchers who have had little experience with microbeams.

The goal of this training course is to give physicists and biologists a thorough and hands-on introduction to microbeam technology. At the end of the course, participants should understand how microbeams work, what experiments can be performed using a microbeam, why these experiments are of biological interest, and how to perform these experiments. ). Because of its intimate nature, it will be limited to 4-5 participants. The course will be designed to emphasize specific needs (e.g., imaging, designing a microbeam facility) as requested by the participants.

The first day will consist of lectures, demonstrations, and a tour of the RARAF irradiation facilities, particularly the charged particle and x-ray microbeam systems. The second day will consist of a demonstration of determining the spot size and position of the beam spot for the sub-micron charged particle microbeam facility. Each participant will then perform these operations individually. After the beam has been characterized, each participant will perform cell irradiations using different irradiation protocols.

Under special circumstances participants will be able to send biological samples before the course and stay afterward to perform microbeam experiments using their own biological systems. Such arrangements will have to be made well before the course and will be subject to approval by the RARAF staff.

The application deadline is 5 p.m. EST, Monday, December 20, 2010.

Learn more and apply to be a course participant:
Contact Steve Marino (sm14 AT columbia.edu) or go to

http://www.raraf.org/microbeamtraining.htm

EMCCD Camera Added to Microbeam End Station

2010-05-07T13:05:00.006-04:00

This week we have upgraded our microbeam end station with the addition of an electron-multiplied charge-coupled device (EMCCD) camera. More about EMCCD technology later in this post.

The EMCCD camera is operating as a direct replacement of our old ICCD (intensified CCD) camera for normal microbeam operations and we are exploring a reduction of the UV illumination of the fluorescent stain (Hoechst 33342) that binds to the DNA in the cell nuclei and is used for target identification. We are working with our biological microbeam users in the further reduction of the amount of nuclear stain used – which can have deleterious effects on its own. Requiring fewer fluorescence photons to be generated in the sample for target detection allows the reduction of the amount of stain and the intensity of the UV illumination required to perform targeted irradiations.

The EMCCD camera has given us an opportunity to reduce potentially confounding factors of UV exposure and stain toxicity in our sensitive experiments, such as bystander effects or genomic instabilities, where very slight effects can have huge ramifications on the experimental results.

The EMCCD technology allows the multiplicative gain of the image pixels directly at the readout of the CCD sensor that is mounted in a vacuum housing and cooled to -70 C by a Peltier cooler, reducing the thermal electrical noise in each pixel to less than 1 electron per read. This allows a single photon to generate a large enough signal to be read as part of an image, making extreme low-light imaging possible on a single sensor without a coupled intensifier. The EMCCD camera technology also allows us to acquire enough signal from the sample in our present setup to target our samples in 1 image frame, where previously several frames had to be aggregated, thus increasing the speed and reliability of the sample targeting.

Hello World

2010-04-30T16:07:00.000-04:00

This is a test entry. The RARAF microbeam blog will soon be updated regularly.