Slajd 1

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The possible influence of the deformation
of the internal structure LumiCal
on deep angle
reconstruction
Michal Karbowiak
Akademia Swietokrzyska, Kielce

• Motivation
• Method
• Results
• Conclusions

In collaboration with B. Pawlik and L.
Zawiejski
FCAL Collaboration Meeting
12-13 February , 2006, Kraków, Poland
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Motivation
Check how big changes are expected in the
calculation of the relative luminosity if an
ideal structure of the LumiCal will be
deformed
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Method
Monte Carlo program for
LumiCal detector simulation
Barbie (Geant 3) was changed to take into
account the possible variations
in position X,Y and Z of the
absorber and sensors layers
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An ideal LumiCal detector
LumiCal - Monte Carlo
Internal structure
One disc structure
sensor
air
absorber
ceramic
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Deformed LumiCal
Deformed structure of the LumiCal was created
by smearing in Monte Carlo X, Y and Z
positions of the layers inside detector. They
were selected randomly according to Gaussian
distributions with average equal to the original
positions and different dispersions
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Changes in X, Y positions
MC simulation
Ideal
Xn Xid XR
Yn Yid YR
Xn , Yn - new discs positions
Deformed
Xid , Yid - discs positions
for ideal LumiCal
XR, YR simulation
XR, YR - random selected X
and Y positions
XR , YR were simulated according to
Gaussian distribution with ? which
was changed from 5 up to 45 ?m in 5
?m step
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Results
X,Y deformation an example
?1 (?r - ?g )id
?2 (?r - ?g )dis
R ? ?1 - ?2 ?
R/?1 265 significant change in
mean value in bias calculation
d1 (??/?)id
d2 (??/?)dis
R ?d1 - d2?
R/d1 ? 47
The expected change in relative luminosity
(?L/L ? 2??/?) can be in this range
The change in relative luminosity ?L/L ? ??/?
this order
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Z deformation
Ideal
After change of the Z postions
ZR simulation from the
distorted type of Gaussian
distribution (? from 5 up to 45
?m)
Z1 Zid Zn1 Zn ?Zid ZR
Z1 , Zid - the position of the first disc
?Zid - the distance between discs
in ideal detector 0.6 cm
ZR - random selected z-position
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Results
Z deformation an example
?1 (?r - ?g )id
?2 (?r - ?g )dis
R ? ?1 - ?2 ?
R/?1 740 significant change in
mean value in bias calculation
d1 (??/?)id
d2 (??/?)dis
R ?d1 - d2 ?
R/d1 ? 182 change in relative luminosity
for random selected z positions (Gaussian
distribution with ? 0.40 ?m)
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Conclusion
The ideal struckture of LumiCal may be
influenced by different factors
like temperature, gravitation which will lead to
its deformation. The preliminary studies of such
deformations by used Monte Carlo Barbie
simulations indicate that such deformation
can change accuracy in the relative luminosity
calculation at level of 150 . Further studies
will be continued