F. Cerutti, M. Mauri, A. Mereghetti

1
ESTIMATION OF PARTICLE FLUENCES IN ELECTRONICS
LOCATIONS

• F. Cerutti, M. Mauri, A. Mereghetti
• for the FLUKA team

2
Overview

• What, why, how
• Radiation levels in UJ56 (and UJ57) high energy
  hadrons
• Available estimates for RR areas
• Conclusions

3
Rationale
4
Single Event Errors
A dedicated working group
T. Wijnands










Radiation To Electronics Taskforce
(R2E) http//ab-div.web.cern.ch/ab-div/Meetings/r2
e/
as a part of its mandate
establish, extend and evaluate the inventory of
information needed to assess radiation-induced
electronics failures
5
UJ56, UJ57, RR57
Looking at IR5
6
FLUKA model of IR5 (present LHC)
Concrete shielding blocks
Triplet
D1
TAN
IP5
TAS
UJ57
UJ56
courtesy of M. Fuerstner (SC/RP) with
contribution of C. Hoa (AT/MCS)
7
gt20 MeV hadron fluence
for a total luminosity of 100 1015 b-1 y-1
(i.e. LL0 for 107 s/y)
vertically averaged over the -60cm lt ylt 60cm
interval (beam axis at y0)
In UJ56, after a 2m concrete shielding, the high
energy hadron fluence at beam level ranges from
1.3 109 up to 1.3 1010 cm-2 y-1
8
CMS shielding effect?
assuming CMS cavern walls as totally absorbing
in fact high energy hadrons in UJ56 come from
interactions between TAS and D1 (Q2)
9
Upstairs
vertically averaged over the 220cm lt ylt 420cm
interval (beam axis at y0)
Upstairs (sensitive electronics) high energy
hadron fluence is in the range 1.2 - 3.6 109 cm-2
y-1
10
Past calculations for RR areas
11
RR17
70 1015 b-1 y-1
optics version 6.4 (_at_20sx)
1.6 1014 protons y-1
0.21 - 6.3 1010 m-1 y-1
12
RR57
13
IR1
14
Conclusions

• Expected high energy hadron fluence in UJ56
  (triplet electronics) is worrying for the present
  LHC at nominal luminosity (with ideal shielding
  without holes)
• Past estimates for the IR1/IR5 RR areas are not
  on the safe side (failure risk related to the
  electronics type). It is worth cross-checking
  them (expected losses at TCLP.4, gas density).
• No simple luminosity scaling for IRP1 (different
  aperture, longitudinal positions)
• New dedicated studies to be planned under the
  coordination of the R2E Taskforce