SiPM for MEG2

On behalf of the italianTC group Fukuoka 23 Oct 2013

Current TC time resolution

Intrinsic TC resolution at BTF is ~40 psIn MEG degradation due to B and to large dynamic range 40 ps → 50 ps expectedAdditional degradation due to DRS (DrS(t) ~30-50ps) → 60 ps (measured with triple, 65 ps is anoverestimation)

Current te resolution

Dominant contribution from t

(TC+DRS) = (BTF)(1+ (MEG))+ (DRS) =

40x(1 + 0.25) + 40 = 60 ps

(BTF) intrinsec (from BTF)

(MEG) relative degradation due to B (low G), large signal dynamic range(DRS) due to DRS

Upgrade TC time resolutionResolution s(t

TC) = 30 (33) ps measured

MEG Additional error (B, extra dynamic range): 1.1

Reduced DRS error: 25 ps

Calibration: 30 ps(???)

Upgrade te resolution

MEG MEG2(my) MEG2(proposal) Intrinsec 40 ps → 30 ps 35 ps MEG factor 0.25 0.1 DRS 40 ps 25 ps TC calib 40 ps 30 ps Le/c 75 ps 35 ps 11 ps--------------------------------------------------- t

e 107 ps 63 ps 37

ps t 67 ps → 64 ps

76 ps ---------------------------------------------------- t

e 122 ps 90 ps 84 ps

te in alternative scenarios

• tTC

intrinsic = 20 ps -> te = 87 ps

• tTC

intrinsic = 30 ps -> te = 90 ps (Hamamatsu)

• tTC

intrinsic = 33 ps -> te = 91 ps (AdvanSId)

• tTC

intrinsic = 40 ps -> te = 93 ps

• s(calibration) = 30ps • The change are tiny.• Limit on->e scales linearly with resolution• But 1 more week/y per extra calibration or commissioning would waste a 3% gain

Calibration and (te

Relative calibration between TC counter(and with XEC) can strongly influence (t

e) Stability of the SiPM is of importantIn particular the thermal coefficients dV/dT should be as small as possible

That is a relevant parameter for deviceswith comparable s(t

TC)

dV/dT = 50 mV/oC for (Hamamatsu) dV/dT = 25 mV/oC for (AdvanSid)

Conclusion

Hamamatsu and AdvanSid are equivalent from the point of view of the effect on t

e time resolution

AdvanSid offers better performance from the point of view of stability that may allow precise calibration

AdvanSid is our preferred choice for MEG2