THE RICH TRIGGER

M.Lenti

M.Lenti 2

The RICH

From the test beam:17 hits @ 35 GeV/c From the test beam: 9 hits @ 15 GeV/c

Dec 9, 2009

M.Lenti 3

PMT: Hamamatsu R7400U-03

• Dark current @ 900 V: 0.5 nA (typical)• Gain @ 900 V: 1.5×10+6 (typical)• Dark rate: 2 KHz/PMT• 2000 PMT: 4 MHz dark rate• Ex.: Multiplic.Trigger with 10 ns window: 1 hit cut: 4 MHz due to dark rate 2 hits cut: 4MHz×4%= 0.16MHz dark rate 3 hits cut: 4MHz×0.16%=6.4KHz dark rateDec 9, 2009

M.Lenti 4

Test beam results

• Hard to disentangle pure dark rate from halo muons….

• Probably the pure dark rate is much smaller than calculated

• A halo muon crossing a PMT give a hit 100ns before the Cherenkov ring hits

• “Spurious” rate in the MHz range

Dec 9, 2009

5Dec 9, 2009

NINO BOARD (NEW)

NINOCHIP

I2clogic

32 PAIR LVDS OUTPOWER

I2C BUS VTH DAC I2C BUS BIAS DAC I2C BUS

FRONT-END CONNECTOR AREA

MULTIPLICITYOUT

NINOCHIP

NINOCHIP

NINOCHIP

4 CHIPs

EXTERNAL PROGRAMMABILITY

Multlogic

FRONT END PCB

M.Lenti

M.Lenti 6Dec 9, 2009

External programming of VTHAND TRIGGER LOGIC

VTH trimmer is located in the center of front-end assembly

Once all board are loaded and connected it is extremely diffucult to change setting.

I2CLOGIC

AND DAC

NEW RELEASE WITH DAISY CHAIN I2C BUS TO DIGITALLY CONTROLL VTH

TRIGGER OUT

LOGICMULTIPLICITY

UNITMULT OUT

IN

OUT

M.Lenti 7

A RICH based trigger

• Using the NINO multiplicity output the n.of channels can be divided by 8 (or more)

• 2048/8 = 256 = half a TDC-TELL1• One TELL1 can be used to provide a

multiplicity trigger from the RICH (about 10 MHz ouput rate)

Dec 9, 2009

M.Lenti 8

The CHOD

• Need an active detector in between the RICH and the LKR to veto photonuclear interaction in the RICH (λ0: mirror 20%, neon 5%)

• Photonuclear interaction: hit in the CHOD and nothing else (no track): no time correction possible

• We need a fast CHOD for vetoeing without too much dead time

• Natural candidate for CHOD: carbon copy of MUV3

Dec 9, 2009

M.Lenti 9

The CHOD trigger

• We need the CHOD for vetoeing• We can use the CHOD for triggering• 10 MHz track rate (but intensity get stronger

towards the center)• Define the dead time to be accepted• Determine the granularity

Dec 9, 2009

M.Lenti 10

The Charged trigger

• It seems to me quite safe:• Have a RICH trigger• Have a CHOD trigger• Decide at the very end what to use as main

trigger and what as control trigger

Dec 9, 2009