Use of ALICE T 0 Electronics for BPTX

Use of ALICE T 0 Electronics for BPTX Readout David Evans • The T 0 detector in ALICE • Requirements of the T 0 detector and electronics • Timetable / Progress of T 0 system • Suitability for BPTX • What next ?

Purpose of the T 0 Detector • T 0 is a triggering detector for level 0 trigger • Gives rough on-line vertex • Beam-gas suppression • Gives rough on-line centrality measurement for trigger • Acts as pre-trigger for TRD

Position of T 0 in ALICE T 0 L -5 < h < -4. 5 T 0 R 2. 9 < h < 3. 3 3. 5 m 0. 7 m

T 0 – the final configuration: • Two arrays of 12 PMTs with quartz radiators – T 0 Right ( + 0. 7 m) – T 0 Left ( - 3. 5 m) • Two shoe boxes of fast electronics inside the magnet (+5 m and – 5 m) • Few creates of electronics outside the magnet • Laser calibration system also outside the magnet

Requirements of T 0 v Precise timing (50 ps) v Fast read-out (used for L 0 trigger) v Event spacing 25 ns (pp) L 1 L 2 L T = L 1 /c – L 2 /c T = (L 1+ L)/c – (L 2 - L)/c = (L 1 -L 2)/c + 2 L/c = T 0 + T Gives vertex to 7. 5 mm

Output Signals v T 0 = (tr- tl)/2+ t v T 0 v = tr-tl (ON/OFF adjustable during run) • T 0 -L, T 0 -R, Coinc • Time and energies (all 24 PMTs) • 3 levels of sum energy – Low – Medium – High

T 0 Timescale / Progress • Draft TDR completed • Final TDR by end of 2003 ? • Prototype of T 0 completed • Electronics prototypes completed • Final choice of timing discriminators to be made • Final configuration of readout electronics to be chosen • Still no final cost estimate (but may use TOF timing electronics – if so, cost per channel ~ 20 SFrs for preamplifiers, shapers and timing). • Production should be completed by July 2005

Suitability for BPTX ORTEC Model pico-TIMING TM Discriminator 9307 Accept inputs pulse widths from 400 ps to 5 ns Time slewing (walk) < 20 ps from -150 m. V to -1. 5 V (Typically < 50 ps for signal amplitudes from -50 m. V to – 5 V. ) Accepts burst rates up to 100 MHz Operating temperature range 0 to 50 C Note: timing of 50 ps is for whole system. Electronics alone have timing better for 30 ps (~ 25 ps) i. e. vertex to ~ 4 mm.

What Next ? Need to clarify some information from the BPTX i. e. what is the physical form of the pulses (including width and height) ? Need to sit down and talk to T 0 group, after their holidays, in order to go through the details. In summary, ALICE has fast (< 30 ps) electronics that we should be able to utilise. Cost of special module for BPTX should be “peanuts” !!