Vincent Lepeltier, our good colleague and friend, suddenly passed away last week, a few days after the Sendai meeting, leaving us full of pain and sadness. We will miss very deeply both his professional and human qualities.

Vincent Lepeltier at the last ILC meeting at Sendai. (Photo: Nobu Toge)

For more than twenty years Vincent was a world expert in gaseous detectors, especially of Time Projection Chambers (TPC) who was based at LAL, Orsay, France. After having worked on all aspects of the DELPHI TPC, and especially its drift velocity monitoring, crucial to obtain a good longitudinal resolution, and a very successful participation to the FFTB experiment at SLAC in the early 1990s, he led in 1996 the small LAL-LBNL-Cincinnati group that designed and built the miniTPC for PEP-II commissioning. He had a lot of pleasure to work on this cheap and robust 20-centimetre-long chamber built to understand and monitor the background produced in the early days of PEP-II running. This chamber profited from all his DELPHI experience but had several innovative features such as a very original slanted pad design. It performed so well that when PEP-II commissioning was over, Brookhaven people asked Vincent to bring the chamber close to STAR and the chamber helped commission RHIC as well!

This experience of building large and small TPCs naturally led Vincent to work for the ILC-TPC. The ILC is a very demanding environment for a TPC since extremely good spatial resolution is required over long drift distances. The two-track separation has also to be much better than during LEP days. Vincent, together with his Orsay and Saclay colleagues, proved that these problems can be solved using gaseous microdetectors such as Micromegas as TPC endplates. They also built a series of successful prototypes, forming the TPC baseline for the ILC.

But Vincent was much more to all of us: his constant smile and good humour and his great kindness will always be remembered. I will personally miss his enthusiasm, so apparent during the last conversation we had together in Sendai where we discussed his future plans concerning the ILC. Vincent had a very endearing personality and made many good friends in our community, as testified by the very large number of sympathy messages received from all over the world. We passed them all on to his wife and three children.

One of Vincent's best friends and colleagues was Mike Ronan, who unfortunately left us as well a year ago. I hope that Vincent and Mike have been able to meet and if it is the case, I am pretty sure they are discussing again right now the design of the ILC TPC!

Our best possible way to honour Vincent's memory now is by trying to build the ILC in a timely way and to use, as one of its central detectors, a superb TPC he would have loved to work with. It is a challenge but we owe it to Vincent to succeed!

-- Guy Wormser, LAL director