1. Dec 22 2006LED monitoring system Beam-test LED monitor Ｊａｎ /23/200 ７ K.Toyama, H.Ono Niigata University, MSU-IIT GLD-CAL

2. Dec 22 2006LED monitoring system Setup of Y-strip 45mm 90mm 10mm 90mm FFC MPPC FPCB 24.7mm FPCB 24.7mm

3. Dec 22 2006LED monitoring system Setup of X-strip 90mm MPPC FFC FPCB 10mm

4. Dec 22 2006LED monitoring system FFC connector board Y-Strip X-Strip Tungsten 3.5mm FFC

5. Dec 22 2006LED monitoring system ECAL assembly LED flush through the white PET sheet. Need to make a small hole on the black sheet ． Black sheet White PET Mega strip LED with FFC

6. Dec 22 2006LED monitoring system Bench test setup ＰＭＴ ＡＤＣ ３ｃｍ 2mm thickness scintillator LED light pass through the white PET sheet. WLSF White PET LED

7. Dec 22 2006LED monitoring system Bias voltage vs light yield (ADC)

8. Dec 22 2006LED monitoring system We can see light yield through sheet 2/3 Light yield reduce by white PET sheet. We can see linearity of bias voltage vs light yield through white PET sheet ADC spec : 0.25pc/count

9. Dec 22 2006LED monitoring system Now Doing Measure how many LEDs can drive by TTL one signal.

10. Dec 22 2006LED monitoring system Problem We planned that thirteen LEDs connect in parallel by NIM-TTL one signal. When we use many LED in parallel, the bias from NIM-TTL module become low. TTL In 5V,25ns Measure by probe

11. Dec 22 2006LED monitoring system Oscilloscope picture from probe 1 No LEDOne LED X axis scale 25ns Y axis scale 500mV Probe makes 1/10V

12. Dec 22 2006LED monitoring system Oscilloscope picture from probe 2 three LEDsfour LEDs X axis scale 25ns Y axis scale 500mV Probe makes 1/10V

13. Dec 22 2006LED monitoring system Three LEDs connected in parallel When we connect three LEDs in parallel, light yield slightly decreased. We didn’t use FFC and MPPC in this time. We used general cable and PMT. LED yield Event frequency

14. Dec 22 2006LED monitoring system Four LEDs connected in parallel When we connect four LEDs,we cannot see light yield peak. Pedestal and light yield are almost equal. Event frequency LED yield

15. Dec 22 2006LED monitoring system Summery and Next We should consider how to drive LEDs, –TTL pulse width should be a little wider? –Reduce LEDs on one board, one TTL drive pulse? Test by MPPC. We already receive all the parts expect for LEDs. It takes only a few days to assemble them.