Update on quadruple well (INMAPS) MAPS rad-hard characterization and strip front-end simulation L. Ratti V SuperB Collaboration Meeting Università degli Studi di Pavia and INFN Pavia September 19-22 2012 Pisa, Italy OUTLINE University of Bergamo and INFN Pavia Massimo Manghisoni, Valerio Re, Gianluca Traversi INFN Pavia Luigi Gaioni University of Pavia and INFN Pavia Alessia Manazza, Lodovico Ratti, Stefano Zucca 4-well MAPS rad-hard characterization charge sensitivity and noise charge collection with IR laser Strip front-end simulations operation at small peaking time in the outer layers operation at lower temperature

4-well MAPS rad-hard characterization Quadruple well MAPS irradiated with neutrons up to 1e14 1MeV eq n/cm2 (JSI, Lubljana) Substrate features: 12 um thick epi-layer, std (~10 W cm) and hi (~1 kW cm) res Charge sensitivity, noise, charge collection (IR laser) measurement

Quadruple well MAPS front-end Charge preamplifier Shaper Discriminator Pixel logic By suitably changing this voltage (in such a way that time to return to baseline is 2 us), the front-end can be made to work in good agreement with simulations (from the standpoint of gain, noise, peaking time)

Waveforms at the shaper output – std res VRIF_MIR set in such a way that the time to return to baseline is ~2us No particular trend detected with the fluence

Noise and charge sensitivity – std res MAPS operated at VRIF_MIR such that time to return to baseline is about 2 us

Waveforms at the shaper output – hi res VRIF_MIR set in such a way that the time to return to baseline is ~2us A trend seem to emerge – peak value decreasing, corrected VRIF_MIR increasing with the fluence  significant (more than in the std res case) increase of the leakage current?

Noise and charge sensitivity – hi res MAPS operated at VRIF_MIR such that time to return to baseline is about 2 us – confirmed decreasing trend in the charge sensitivity with fluence

After a neutron fluence of 1e14 cm-2 Laser tests Infrared laser, l=1064 nm, step=5 um, sigma of the laser spot=3 um Before irradiation After a neutron fluence of 1e14 cm-2 Sample from the std res set

Laser tests – normalized peak value Higher degree of radiation hardness for the hi res case (maybe not as high as expected)

Strip front-end simulations Operation at smaller peaking times in the outer layers (to overcome noise issues due to leakage increase in irradiated devices) Operation at DT=-6 °C (assuming RT=20 °C) Detailed presentation by Massimo Manghisoni (including data on the individual contributions from the different noise sources) uploaded with this same presentation

Detector model and parameter from the latest fluence estimate

Equivalent noise charge for inner layers (0-3)

S/N @1 MIP for inner layers (0-3)

ENC and S/N @1 MIP for outer layers (4-5) Same chip for the outer layers as the one developed for the inner layers

Optimum S/N @1 MIP for outer layers (4-5)

Conclusion Rad-hard characterization of quadruple well MAPS in progress – first results confirm higher tolerance for hi res substrate Operation of the strip front-end at small peaking times might help keep S/N above 10 also after several years in the experiment At such small peaking times, the advantage of operating the system at 6°C (probably also 8 °C) below RT seems negligible