The 3mm Global VLBI spring session took place on May 4-8 this year. Pico Veleta participated using the NCS and its new capabilities, only limited by bad weather conditions at the beginning of the session. Plateau de Bure experienced a breakdown of its CNRS maser five days before the session, which could not be repaired although a specialist from the OCA (Observatoire de la Côte d'Azur) came to the mountain. This resulted in a 100% loss of the Plateau de Bure phased array in the session. The CNRS maser has already returned to its laboratory in Grasse, where it will be repaired and renovated to play a role in Earth-space-Earth time transfer experiments.
IRAM has ordered in 2005 (with an important contribution by the MPIfR Bonn) a new active hydrogen maser at the Observatoire de Neuchâtel, with a construction time of 15 months. If everything goes according to plan, the new maser will be installed in summer 2006 at the Plateau de Bure. The EFOS-C maser series by Neuchatel is a synthesis of robust Russian technology and Swiss precision, and the specifications for the Plateau de Bure unit were chosen to allow VLBI observations up to 350 GHz. The maser on Pico Veleta is also a Neuchâtel model (EFOS-B series, delivered in 1991), which has already permitted in 2003 VLBI observations at 230 GHz with an excellent stability.
With the new Plateau de Bure maser and the planned Bure receiver upgrade (with two simultaneous polarisations), the stability and sensitivity of the phased array will improve considerably.