december 5, 2007 p. colas - lp cosmic trigger 1 the cosmic trigger for the large prototype th....

December 5, 2007December 5, 2007 P. Colas - LP cosmic triggerP. Colas - LP cosmic trigger 11

The cosmic trigger for the The cosmic trigger for the Large PrototypeLarge Prototype

Th. Chaminade, P. Colas, K. Dehmelt, G. De Lentdecker, X. Janssen, Y. Kato, H. Kuroiwa, Y.

Kudenko, T. Matsuda, F. Pierre, J.M. Reymond, S. Turnbull


The Large The Large PrototypePrototype

Cosmics in March 08Beam summer 087 panels mid 09


Slab size changed to 167 mm (better extrusion)Suggestion (by Takeshi Matsuda and Dean Karlen)Use MPPCs and scintillating slabs from T2K/SMRDFace-to-face meeting on October 11 in Orsay allowed revisiting the layout and plans

K. Dehmelt


The trigger has to be in a field of order 0.4 T.MPPC : multi-pixel photo counters (so-called Silicon PM) produced by Hamamatsu100 pixels on 1 mm2. Each is a Photodiode in Geiger modeOperation voltage : Vbreakdown + fraction of a VoltRequires accurate supplies about 70 V. Need to sort the MPPCs in Vbreakdown to reduce the number of supplies.Signal: 3 mV/p.e. ( 10-20 p.e.)Dark counting rate and Vbkd sensitive to temperature : needs good temperature control: Peltier devices + thermo.

1mm


The gain depends on Vbias, and Vbreakdown depends on the temperatureRequires both a stable and precise supply and a controlled temperature.


Box with photocouplers, MPPC, R,C circuit,Thermistance, Peltier device

Wavelength shifting fiber

Scintillator slab

ControllerTrigger logicTLUSupply

Temperature control: Jean-Marc Reymond


Mechanics can be simple: wrapped slabs maintained by barsTylic reflector to be ordered


5 slabs on top

3 slabs at bottom+4 perpendicular to limit the triggers to the detector length

Present layout:12 slabs (+ 3 spare)Many possible combinations, for instance: 1 top + 1 bottom : central region of central panel3 top + 1 bottom : radial tracks on central panels3 top + 3 bottom : vertical tracks on most of the central regionRequires a ‘bridge’ to support the magnet and its movement system.


First step : hands on MPPCFirst step : hands on MPPC Build a box with Build a box with

1MPPC and one 1MPPC and one diode and a diode and a readout circuitreadout circuit

Advices from J-Ch Advices from J-Ch Vannel Vannel (Polytechnique), (Polytechnique), H. Kuroiwa and Y. H. Kuroiwa and Y. Kato, and I. K.Kato, and I. K.


Second step : choose Second step : choose suppliessupplies

Must be accurate and stable, low-ripple, Must be accurate and stable, low-ripple, especially around 70 V. Candidates:especially around 70 V. Candidates: Keithley 2612, Keithley 237Keithley 2612, Keithley 237 Modules from NIKHEF (Jos Steijger) in a Caen Modules from NIKHEF (Jos Steijger) in a Caen

SY527 crate (K.Delmeht). But maybe not SY527 crate (K.Delmeht). But maybe not accurate enoughaccurate enough

Need also 24 channels of PMT amplifiers Need also 24 channels of PMT amplifiers and discriminators, coincidence units and discriminators, coincidence units


Third step : design readout and Third step : design readout and thermalisationthermalisation

3 parts top, bottom parallel, bottom 3 parts top, bottom parallel, bottom perpendicular.perpendicular.

In each box: thermistance, peltier In each box: thermistance, peltier devicedevice

In a central place : controlerIn a central place : controler Design mechanics, system, cablesDesign mechanics, system, cables Light-tightness vs accessibilityLight-tightness vs accessibility


Conclusion and plansConclusion and plans Need a robust system: temperature Need a robust system: temperature

controlcontrol Characterize MPPC, decide on Characterize MPPC, decide on

supplies, Finalize design.supplies, Finalize design. Slabs delivered from mid-JanuarySlabs delivered from mid-January Wrapping in Saclay 2 weeks afterWrapping in Saclay 2 weeks after Installation in February or MarchInstallation in February or March Connexion to DAQ in MarchConnexion to DAQ in March

december 5, 2007 p. colas - lp cosmic trigger 1 the cosmic trigger for the large prototype th....

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