STATUS OF MUV3 CONSTRUCTION
A joint IHEP Protvino – Mainz – Pisa project
MUV3
 Proposed by Italo Mannelli:
Thick scintillator tiles with direct light collection by PMTs through air
 Design evolution to two PMT’s per tile to identify and reject
early signals from Čerenkov light produced by muons crossing
the PMT window ⇒ improved time resolution
Test of a cell with two PMTs on a PS beam in August 2010
(see presentation by R. Wanke at the MUV Group Meeting, 8 Sept. 2010)
 Final mechanical design available at the end of 2010:
frames of commercially available light Al tubes (purchased by Pisa),
thin black Al septa to provide optical separation between adjacent cells,
Iron plates to provide mechanical rigidity and support to the scintillating tiles
and PMTs. All mechanical components, including PMT fixing collars, built in Protvino.
 Almost all PMTs available from the NA48 AKL system (tested in Mainz)
 Assembly of the two half-modules at CERN during November 2011
by E. Chernov, K. Kachnov (Protvino), A. Bianucci, C. Cerri (Pisa)
L. Di Lella (Pisa), 14 Dec 2011
Sketch of the MUV3 detector
12 x 12 cells with 22 x 22 cm scintillator tiles except for the region near
the beam tube where 2 x 2 cells are replaced by 8 smaller cells:
in total, 148 cells (296 PMTs)
Scintillator tile configuration near the beam axis
Half tiles → half cells
become full cells when the two half modules are joined together
Structures of light Al tubes
manufactured by Bosch
(two frames connected together for each MUV3 half-module)
Installing the scintillator tiles
Scintillator tiles are fixed to the
MUV3 front plate by four special screws
Temporary bar
will be removed
when the two half-modules
are joined together
PMT supporting plates and light septa
before installation and connection
to the scintillator tile support
The first MUV3 half – module is (almost) completed
and is moved away from the assembly tables
Still missing:
 additional side walls for
light tightness
 MUV3 “feet” with special
sliding blocks to slide
the two half – modules
in their final positions
The 2nd MUV3 half – module is completed
(week of 5 December)
A MUV3 “foot” with one sliding block mounted on it
Sliding blocks and matching rails are commercially available (Bosch)
Position
of the 2nd sliding block
Sliding block
During the week of 5 December two PMTs have been installed
on one cell together with two partially overlapping scintillation counters
located under half-module 1 to provide a cosmic ray trigger
(I. Mannelli, A. Khudyakov)
See presentation by A. Khudyakov for the results from this test
CONCLUSIONS
 The construction of the two MUV3 half – modules is practically
completed
 Still missing: PMT installation (foreseen for January 2012)
We need 296 PMTs – we must buy ~20 additional PMTs and bases
to complete the installation for the whole MUV3 and have a few spare
PMTs available during the experiment
 It is planned to test all cells with cosmic rays using the final
electronic chain before installation in ECN3