JRA 23 (DPS-FA) ‏

1. JRA 23 (DPS-FA)‏ Q1 – The core activity of Digital Pulse Shape from FAZIA R&D Optimization of Silicon material for Pulse Shape Analysis applications. Presently the PSA technique is far from being fully exploited, because two non-intrinsic limiting factors, i.e. channeling and silicon doping non-uniformities. Channeling: proper choice of the cutting angle of the Silicon wafer eliminates the problem Doping non-uniformity: close co-operation with Silicon industries / detector manufacturers is necessary, together with the development of lab-based uniformity-test techniques Preliminary contacts with CANBERRA, TOPSIL, IRST/ITC confirmed the interest of specialized industries to co-operate Q1, Q2… refer to item1, 2 of the questionnaire G.Poggi Helsinki 19/09/2007

2. Current waveforms for 80Se @ 405 MeV stopped in Silicon (LNL, Legnaro) “Pulse-Shape based Crystallography” Silicon detector mounted on a two-axis Goniometer ions E “Random” “Channeled” DigitizedCurrent DigitizedCurrent ns ns E JRA 23 (DPS-FA)‏ CHANNELING Channeling directions: wildly fluctuating current shapes – to avoid for PSA Random directions: narrow current shapes – good for PSA For optimum PSA performances special cut of Silicon wafer is necessary, at the cost of limiting the angle covered by each individual crystal Also standard ΔE-E identification technique will benefit of channeling removal (a too often overlooked issue) G.Poggi Helsinki 19/09/2007

3. Risetime distribution for 58Ni @ 700 MeV as a function of the impact point on a “random” oriented nTD-Silicon detector (LNL, Legnaro) Random More than a factor of 2 improvement Full area Selected area Lab test with Pulsed UV laser scanning In beam test with 60Ni @ 700MeV Lab test with 5MeV α-particles (~standard) JRA 23 (DPS-FA)‏ Current risetime distribution (PSA) for the demanding study case of 58Ni and 60Ni @ 700 MeV Non-uniformity of Silicon Doping Doping non-uniformity of Silicon: a limiting factor for PSA and timing Silicon Industries must improve striation control: even nTD silicon has significant residual resitivity striations We will develop bench tests to control the doping, i.e. resistivity, uniformity G.Poggi Helsinki 19/09/2007

4. JRA 23 (DPS-FA)‏ • Q2 – Is the JRA innovative? • Reduction of residual resistivity striations in the nTD Silicon of a few kcm would certainly constitute an important innovation in itself • Resistivity measurements by pulsed UV laser scanning is a promising technique (and novel from many respects) • Optimization of Pulse Shape Analysis in Silicon will give support to Nuclear Physics research Q3 – How European Nuclear Physics will benefit... PSA in Silicon detectors is strategic in Nuclear Structure and Reaction studies (see many talks and posters during this meeting)  existing Access Facilities, like GANIL, INFN (LNL-LNS), GSI, KVI will certainly benefit form this activity G.Poggi Helsinki 19/09/2007

5. JRA 23 (DPS-FA)‏ Q4 - Overlap with other EU activity.... FAZIA is involved in WP5 of SPIRAL2 Preparatory Phase (now under negotiation). No support has been asked for that specific issue, i.e. optimization of Silicon Material for PSA Q5 - Institutions expected to provide substantial support to JRA 23: CNRS-IN2P3 and GANIL (France), INFN (Italy), IFIN-HH (Romania), COPIN – Consortium of Polish Institutions (Poland), UNIVERSITY of HUELVA (Spain) G.Poggi Helsinki 19/09/2007

6. Thank you