The Zero Degree Detector
for BES3: design status
Fare clic per modificare
stile del
sottotitolo
dello schema
TheloLNF
ZDD
group
ZDD (Zero Degree Detector) @ BESIII
ZDDB
ZDDF
Fare clic per modificare lo stile del sottotitolo dello schema
349cm
Proposal accepted by INFN: substitution of one (in 2010-2011) luminometer with
a mini-calorimeter based on the KLOE Pb/Scintillating fibers technique
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1° prototype (courtesy of P326 – thanks!), machined in early September 2010
Weight approx. 5 kg
Fare clic per modificare lo stile del sottotitolo dello schema
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Picture of Pb/Sci.Fi. Array, scintillating material 60% of total (in volume)
Fare clic per modificare lo stile del sottotitolo dello schema
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Present BESIII Lumi detector
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Tungsten plate
10mm Thickness
Tungsten plate
6mm Thickness
Lead-Scint.Fibers Brick
g Beam
No material on this side
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Max avalaible space
65mmx180mm
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6
Lead-Fibers Brick
The opposite faces of the two bricks must
lift:
a) – Up, to 45mm from the beam;
b) – Down, to 5mm from the beam.
Lead-Fibers Brick
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Lead-Fibers Brick
per modificare lo stile del sottotitolo dello schema
….why the hole?
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Lead-Fibers Brick
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7
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82
Torque: 5Nm
Load: 6Kg
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45mm
120mm
60mm
Lead-Fibers Brick
Structural glue
Back support
plate (Al alloy)
Brick weight: 4kg
Double layers of
scintillating strips
Pins
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What are these??
Light-Guides to 4
PMs “close” (2 m)
to ZDD
Light-Guides to 4
PMs “close” (2 m)
to ZDD
Aluminum-Box (0.5mm thickness)
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Bundles of clear plastic fibers
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Cover plate
Back support
profile
Light guide
BES_3 Total weigth: 30Kg
(Without the “light-guides”)
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Base plate
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Pictorial view
Motor
Actuator
Actuator
Motor
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Brushless motor Mitsubishi HC-PQ053.
Actuator THK KR-1501AM100.
-Stroke: 56 mm
-Torque: 12 Nm
- Material: AISI 404
(martensitic steel-magnetic)
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Step 1
Brick (and fibers!) transverse
area: 40 mm x 140 mm
Step 2
Step 3
Light
guides
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“Fixing System” hypothesis.
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DAQ schematics
BESIII Counting Room (20 m away)
ON-LINE monitoring
Monitor Out
CAEN V1190B TDC
64 chs multievent TDC
VME
Processor
Front end electronics,
by the detector (2 m away)
CAEN V1721 DIGITIZER
8 chs - 8 bits - 500 MS/s
(1 out of 2)
Single-Ended
To
Differential
Vth1
Vth2
Double Threshold
Discriminator
DAQ
(CH 1) out of 16
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Front-End electronics
Splitters and discriminators must be located
close to the detector
Some structure needs to be studied and
constructed, to hold:
16 PMs (8 up, 8 dn) and fiber bundles
cables: analog OUT (16 x 3 = 48),
discriminators OUT (16), PM power IN (16),
(discri threshold IN?) ~20 kgs of electronics
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Possible DAQ problematic areas
1) These modules are 6U VME modules, and
need a 6U VME crate.
2) Most of BES-III DAQ is housed in 9U crates.
Does BES-III include a 6U crate, with its (BESIII compatible) controller? Is there another
controller (or crate) that we can use?
3) If not, can BES-III accommodate a 6U
controller, and of what kind?
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Things to do
(few of the very many……)
1) Study the interface with the support beam:
can we use the threads of the present
luminometer pedestal?
2) Project and build the front-end support
3) Study the interface with the present BES-III
DAQ
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August survey of the region, no Lumi detector, side view
Present luminometer
pedestal (185 mm)
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We need some help!
1) Starting from now, a BES-III responsible for
projecting and building the frontend support
structure, and for the interface to the steel
support beam.
2) Starting “soon”, a BES-III DAQ
hardware/software expert to implement
with us the read out of our detector, on a
BES-III trigger
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Acknowledgements
All engineering drawings in this talk were made
by Dario Orecchini, of LNF SPAS (Service for
Project of Experimental Apparatus), that we
gratefully acknowledge together with its head
B. Dulaq, A. Cecchetti, and all others.
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