Saturday, November 11, 2006

Book festival 2006

The fourth Bangalore book festival has begun in Palace grounds from today and it will go on till 19th November. This festival has been organized by Bnagalore book sellers and publishers association, Festival hours: 11 a.m to 8 p.m. everyday. The ten days book carnival draws people from all corners of Bengaluru. This is a ticketed book fair and the ticket price is Rs. 20/-. Today I went to the book fair along with Deep and Santanu. It was Saturday and the crowd was thin inside the fair. We had plan a to identify stalls which we will target for thorough browsing first and then move to the others. It wasn’t a big fair so within half an hour our targets were identified and then we started our close look sessions. There were few publishers who brought the technical books: Oxford, Cambridge, Orient Longman, CBS are the places where we found some technical stuffs. There is a good collection of old and new books. Though the collection of classics is probably not much as Santanu appeared disappointed, but this was just the first day and I know we can explore more. There are few books which you can find in lots of stalls; Kiran Desai’s “Inheritence of loss”, Orhan Pamuks’ collections, Chetan Bhagat hovered the book fair. John Grisham or Jeffry Archers’ presence you can feel from the time you step inside the fair. Absence of stall from strand book shop was noteworthy! All three of us bought few books. Deep took wide spectrum of collection! Fron Sheila Dhar to Amitav Ghosh, I bought couple of books: “Maximum city” by Suketu Mehta and a small biography of SN Bose. There are 8 PCs with net, available in the book fair premises which are providing a soft copy of the book catalogue and also some details about the festival, few food stalls are also present outside the bookstall premises, to fill the stomach of the book worms and a stage where cultural programs will be held.
The experience of this festival is quite different from the “Kolkata Boi Mela”, well there can not be any comparison here, and still it’s a good effort in a city where people are becoming comfortable reading e-books. I am looking forward to visit the fair few more times and explore some more stuff, old habits doesn’t disappear soon!

Word of caution: avoid visiting the place when crowded. The stalls are small and become quite stuffy when crowded in the daytime.

Friday, November 10, 2006

Little bit of SIMS

Spectroscopic techniques have pushed the materials research a notch ahed, whether its grain boundary segregation or higher phosphorus content in steel, spectroscopy have proved to be determining tool in these field of research. Secondary ion mass spectroscopy is another such technique used primarily for determining diffusion of elements inside a material through various processes. Whether its lattice or grain boundary diffusion, whether it’s a two phase material or a single phase, SIMS has provided very accurate diffusivity measurement.
How it works? Well the mechanism sounds quite simple but the instrumentation is not so simple. An ion beam is used for scan over the surface of the specimen. This powerful beam of O+, Cs+, or O- takes out material from the surface of specimen. O2 or Cs gases are ionized in duplasmtron and using few electrostatic lenses they are focused on the specimen. This beam ionizes the materials from the surface and takes out materials from the specimens. After the ions flies from the surface, they travel under a potential different. Lenses and filters take out the high energy ions from the ion flow. These ions are mass separated in a magnetic separator where the ions are separated depending on their mass to charge ratio. Another technique used for mass separating the ions is through quadrapole where crtical voltages are applied to separate specific ions. In case of magnetic separator the trajectories of the flying ions are exploited, the ions with different mass to charge ratio have different trajectories.

Schematic of the column in which the ion moves. courtesy Cameca

The crater which forms due to the rastering of the ion beam covers a region of 250  250 ┬Ám. The depth resolution of this instrument sometimes will be as high as 1-2 nm. New generation SIMS now-a-days provides secondary electron imaging facility, so it is possible to identify phases or elemental changes in the material. This technique is also useful for studying interfaces in the semiconductor devices or measure lattice and grain boundary diffusivity independently. A major use of SIMS is in locating impurities in the materials, xray spectroscopy or other spectroscopic technique many a time fail to present the information that can be achievable through SIMS.
Presence of C and O impurities in a bonded Si wafer. Courtsey Ansto

Many companies in the world make SIMS, as I took picture from the web pages of companies I am providing the link below.