Sistema di distribuzione laser

Presentazione sul tema: "Sistema di distribuzione laser"— Transcript della presentazione:

1 Sistema di distribuzione laser
C.Ferrari, A.Fioretti, C.Gabbanini, G.Venanzoni INO, UOS Pisa, Via G. Moruzzi 1, Pisa LNF, INFN Frascati

2 Outline: Schema baseline finale Stato del pannello
Sistema baseline: motivazioni scelta diffusore (vs. sfera) Schema baseline finale Stato del pannello Test stabilità catena di distribuzione Budget energia Conclusioni

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4 Risposta temporale: Sfera Diffusore
Uniformità spaziale: Sfera Diffusore ~ 1-2% regolabile (> 2-3%) Trasmittività: Sfera Diffusore ~ 1% regolabile ~ 10% (tot.su bundle fibre 1mm) (tot.su bundle fibre 1mm)

5 Uniformità spaziale / Trasmittività
with lens sphere no lens no lens

6 Diode Laser from Picoquant
Multilaser 8 channel sepia LDH-P-C-405M A crate+driver+1 head arrived Wavelength: 405 nm ± 10nm Pulse FWHM: < 700 ps Average Power 40 MHz): 28 mW Power stability 12h, DT < 3K: 1 % RMS, 3 % p to p Measured light output: 10 kHz

7 Schema baseline PANEL X 24 Laser hub Calorimeter RING Laser control f
Local Monitor DAQ, Slow Control Calorimeter Fiber collimator 50/50 Fiber bundle Laser control Source Monitor Launching fiber Diffuser filter wheel Local Monitor laser1 T80/R20 50/50 50/50 laser2 X 24 laser3 laser4 laser5 laser6 RING Laser hub

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9 Pannello PMMA fiber Prism PbF2 crystal SiPM

10 Distribuzione luce in uscita dai cristalli
Fibra 1mm PMMA NA=0.49 Disomogeneità 3% integrata su 12 mm (dimensione SiPM)

11 Misura della trasmissività della linea di distribuzione con power meter

12 Distribution system transmission: 6 lasers/ 24 diffusers
Element Transmission Energy (pJ) Notes Laser Picoquant output 1000 100% current intensity Source monitor sampling 80% 800 200 pJ/pulse for the source monitor (2 PD and 1 PMT) Filter wheel 100% Division into four fibers 25% 200 Fiber coupling + 25 mt quartz fiber 160 Measured Diffuser with bundle (54 fibers) + 3 local monitors 10% 16 It can increased by reducing uniformity 1 mt bundle POF (200 dB/km) 90% 14.4 Prism coupling 65% (1stmeasure) 9.4 Prism with anti-reflection coating and with metallized reflecting face PbF2 crystal reflection + absorption (20%) 6.0 without optical grease we expect 75% Total per calorimeter Required: 0.6 pJ /pulse /calorimeter Distribution system transmission: lasers/ 24 diffusers Required value of the output of each crystal: 0.01 pJ/pulse; for each calorimeter: 0.6 pJ/pulse

13 Energia in eccesso utile per processo calibrazione SiPM

14 Stability of distribution system (a few pJ/pulse at the PINs)
diffuser PIN2+CREMAT CAEN DT5730B Laser launching fiber (f=600 mm) PIN1+CREMAT Fibers PMMA 1mm sistematico ~ /h

15 Conclusioni Lo schema con 6 laser e 24 diffusori è un ottimo compromesso per: energia ai SiPM stabilità sostenibilità dei costi modularità approvazione degli americani In corso di progettazione e realizzazione un prototipo di catena completa di distribuzione (dal laser al pannello baseline) per portare al test beam (gennaio a SLAC?) o a Seattle

16 SPARES

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18 Diffuser Engineered diffuser ED1-C20 by RPC Photonics – sold by Thorlabs

19 Transmission coefficient- sphere
Fibers are grouped in two classes with different transmission This is due to the bundle and not to the sphere: infact, by changing port for the bundle, the behavior is unchanged The transmission coefficient among the two groups differs by 10%. Within each group just by 2%. The transmission coefficient is: Ti = (1.01 ± 0.03)· 10-5 or Ti = (0.91 ± 0.03)· 10-5

20 Transmission coefficient- diffuser
Measurements with/without collimating lens changing the distance diffuser-bundle or lens/bundle Inhomogeneity strictly connected with transmission coeff.

21 Transmission coefficient- diffuser
with lens sphere no lens Inhomogeneity strictly connected with transmission coeff. Best results: without lens 5.7% in a bundle group T= (new with square pattern diffuser: 4%) with lens % in a bundle group T=

22 Light uniformity map Pulsed laser Nd:YAG, l = 532 nm, 20 Hz repetition rate, 10 ns pulse width; model: Continuum Surelite I-20 Pentax camera (mod. K100D), with a short shutter time (1/30 s) to acquire a single shot Sphere: camera acquires radiation coming from a specific portion of the sphere inner surface. Diffuser: camera without lens placed instead of bundle

23 Sphere Data averaged over 900 pixels (1mm):
Uniformity of the order of 0.982, in the central part up to

24 Diffuser no lens 2% inhomog. on 0.2 mm in the central zone with lens