V 0 A design and development Building process

V 0 A, design and development

Building process Conventional tools has to be adapted for the high quality requirements Especial glue High reflectivity and good mechanical bounding

Test 2002 V 0 L Prototype. Rings 1 and 2 • Made with the Megatile technique. • BC 408 plastic scintillator. • WLS fibers on one face only. • Y 11 and BCF 92 WLS fibers tested. • Teflon and Aluminum wrappings tested. • Prototype tested in September 2002 at the PS accelerator at CERN.

Beam Test

Results from Tests Counts Single photoelectron calibration. Counts Channel Light collection from MIP´s Element of ring 2, with 3 Y 11 WLS fibers and Al reflector. Channel

BCF 92 Using K 11 requires ~70 p. e. to achieve 1 ns resolution. Can Bicron fibers improve the time resolution? (specially for ring 4 and 5).

Test 2003 V 0 L Prototype Rings 4 and 5 • New megatile design preserving thickness of 1 cm. • WLS fibers on both faces.

Projections of the previous plot: Light collection from MIP´s Element of ring 5, with 22 WLS fibers and Teflon. TDC spectrum of an element of Ring 5. Sigma=0. 836 ns.

Fitting function

Test 2004, Scintillator 2 cm, with fibers BC 99

WLS fibers being inserted

Position dependence

ALICE : V 0 A PROTO 0 TEST May, 2005 POSITIVE VOLTAGE (SLOT 0) NEGATIVE VOLTAGE (SLOT 1) CHANNEL 0 PALETA 1 (P 1) 1 PALETA 2 (P 2) 2 V 0 3 TRIGGER 1 (T 1) 0 TRIGGER 2 (T 2) GEOMETRIC DIMENSIONS 43 cm AL LA TER 19 cm P 1 FRONT T 1 P 1, P 2 19 cm 6 cm T 2 8 cm cm PROTO 0 P 2 T 1 m 12 cm V 0 10 6. 5 cm 3 c All detectors (P 1, P 2, T 1, T 2) have width = 1 cm 35 cm T 2