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Malek MAZOUZ n-DVCS/E03-106 status report -Tagger description -Electronics -Experimental tests -Mechanics -Simulations The 18 th of May 2004 Hall A collaboration.

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Presentation on theme: "Malek MAZOUZ n-DVCS/E03-106 status report -Tagger description -Electronics -Experimental tests -Mechanics -Simulations The 18 th of May 2004 Hall A collaboration."— Presentation transcript:

1 Malek MAZOUZ n-DVCS/E status report -Tagger description -Electronics -Experimental tests -Mechanics -Simulations The 18 th of May 2004 Hall A collaboration meeting LPSC Grenoble

2 Mostly sensitive to GPD E (unknown !) Information about quark orbital angular momentum through models and Jis sum rule Use of a deuterium target Proton DVCS ( e d e γ p (n) ) is veto-ed by new detector Detection in Left HRSDetection in PbF2 electromagnetic calorimeter Detection in proton array (~20% of efficiency) M. Mazouz

3 Tagger Two scintillator layers: -1 st layer: 28 scintillators, 9 different shapes -2 nd layer: 29 scintillators, 10 different shapes M. Mazouz Proton array

4 The 57 scintillators of the tagger M. Mazouz

5 The light guide is glued to the scintillator using a UV glue M. Mazouz

6 Scintillator and its guide are wrapped with aluminium and black tedlar M. Mazouz

7 All tagger scintillators and light guides are glued and wrapped (thanks to Kathys hard work!) M. Mazouz

8 Electronics : LPC Clermont-Ferrand supplied and tested 70 PMTs and determined their characteristics M. Mazouz Hamamatsu R7788 PMT -# of dynodes : 8 -Gain at 650 Volts : Rise time : 1 ns -Decay time : 2 ns LPSC Grenoble designed and tested the PMT bases. To reduce the dynode current: Reduction of the PMT Gain Use of an amplificator (gain~10)

9 Amplification board HV distribution board PMT LV (+/-5V) daisy chain connectors HV-Signal-DC out Connectors PMT + base 5 cm M. Mazouz

10 PMT box At present we are testing the set {PMT+base+light guide+scintillator} Assembled paddle M. Mazouz

11 Experimental Tests Scintillator S1 Wire chamber H Wire chamber M Wire chamber B Prototype Scintillator S2 M. Mazouz

12 Light collection uniformity Wire chambersCoordinates of each event Paddle light collection map for each cm² : : Number of events in this cm² : Total number of events per paddle : Relative average Amplitude in this cm² events Amplitude (mV) Amplitude histogram for a paddle (1 st layer) M. Mazouz

13 Light collection uniformity Light collection map for the five different shapes of the first layer. The variation of the light amplitude is about 30% at most. Paddles of the 2 nd layer are being tested this week. M. Mazouz

14 Mechanics: The main shielding : built by the workshop of LPSC Grenoble The middle shielding (between the two scintillator layers) and the light tight cover will be finished next week. M. Mazouz

15 Simulations: The final geometry of the tagger has been introduced in the simulation program GEANT Studies to be performed: -Background rates in the two scintillator layers -Neutron detection efficiency of the proton array -n-DVCS events distribution in the detector -… M. Mazouz

16 Planning : -Delivery time of cables and connectors : next week -Detector Assembly at LPSC Grenoble : 3 rd week of June -Shipment to JLAB : End of June -Detector assembly and tests at JLAB: July -Hall A installation: August -Beginning of DVCS experiment: 20 th of September -n-DVCS experiment: from October 31 st till November 24 th M. Mazouz

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