3 calorimeters

1
3 calorimeters for the best DVCS photon
interception and ? rejection
N. dHose 27 June 2007
2
Large difference between 0.1 lt y lt 0.85 and
0.03 lt xBj lt 0.27
y0.9
y0.8
y0.5
y0.2
Traditional cut
y0.1
y0.05
New cut envisageable
? max

• ? when Q2 ?
• or when xBj ?

0.03 0.07 0.13 0.27
xBj
3 xBj bins of study ? for 0.13 lt xBj lt 0.27
necessity of y ? 0.05
3
Acceptance of the DVCS photons
0
X0.13
X0.27
??lab (deg)
??lab (deg)
??lab (deg)
At small xBj lt 0.03 the DVCS ? are in ECAL2
hole At 0.03 lt xBj lt 0.07 and 0.07
lt xBj lt 0.13 The DVCS ? are
mostly in ECAL12
At
0.13 lt xBj lt 0.27
The DVCS ? are mostly
outside ECAL1
4
ECAL1 and ECAL2 in 2006
From detectors_54507_minus.dat
Mainz
OLGA

• ECAL1
• L x H 3.97 x 2.86 m2
• Hole 1.07 x 0.61 m2
• ECAL2
• L x H 2.45 x 1.94 m2
• Hole 38.2 x 38.2 cm2

20
GAMS
2.86
24
16
28
44
13
8
22
3.97
GAMS
size cm2 used available?
10
?
1.83
48
?
GAMS 3.83 x 3.83 3580 4900 MAINZ 7.5
x 7.5 572 700 OLGA 14.3 x 14.3
320 320
10
64
2.45
0.38?
3.21
5
Half acceptances
SM2
Horizontal
ECAL1
ECAL2
SM1
56
286
179
37
6
48
Vertical
190
129
6
28
_at_ 4 11.11 18
33.25 m
6
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7
Present size of the calorimeter (as indicated in
the 2006 files)
JURA side
ECAL1_at_11.11m 3.4m
ECAL2_at_33.25m
-143cmltvertlt143cm
-91.92cmltvertlt91.92cm
-198.66cmlthorilt198.66cm
-122.56cmlthorilt122.56cm hole in the
middle -30.64cmltvertlt30.64cm
-19.15cmltvertlt19.15cm
-53.62cmlthorilt53.62cm
0cmlthorilt38.3cm
8
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9
The various ECAL detectors

• GAMS
• 4900 LG blocks available
• 38.2 x 38.2 x 450 mm3
• OLGA (NA14, WA92)
• 320 SF5 LG blocks available
• 143 x 143 x 470 mm3
• Mainz (WA89)
• 700 SF57 LG blocks available (WA)
• 75 x 75 x 360 mm3
• Papardelle/Shashlik
• Rad Hard, sandwich-type detector, to be build
• 800 channels
• 38.2 x 38.2 mm2

10
ECAL1 in 2006
Beam line
1.6mm Fe
Mainz blocks 75x75 mm2
Jura
Saleve
GAMS blocks, 38.3x38.3 mm2
11
ECAL1 in 2006
GAMS blocks, 38.3x38.3 mm2

• Disadvantages
• Gaps between Mainz lead glasses blocks
  (degradation of energy resolution near gap)
• Modification of the ECAL1 cassette
• Three type of lead glasses blocks, PMT, HV bases
  and
• Worse space resolution, factor ?2
• RW will be more important, as preshower detector!

Mainz blocks 75x75 mm2
1.6mm Fe
12
ECAL2 in hadron setup
SADC

• ECAL2 dimensions 2.44?1.83 m2 ( matrix 64?48
  with 2?2 central hole), 3068 blocks, 3068 ADC
• 2044 channels ( 32 FIADC ) 1024 channels ( 32
  SADC)
• Calibration, 40 GeV e-, end of October
• 40 GeV ? 600 ADC counts

FIADC
SADC
13
Possible improvement WAD (similar than DVCS
calorimeter?)