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topIntroduction

LHC environement is specific, being different from known radiation environements like space or nuclear plants, for 2 main reasons:

  • Type of radation and particle type and energy ranges.
  • Failure dependance, not as critical as in space applications (acceptable non-null failure rate).

topLHC Layout

Irradiations conditions will be dependent on the machine location, regarding identified main sources (combinations possible in some locations):

  • Collimator-like Losses (beam cleanning, injection protection and dump protection).
  • Particles secondaries (debris from beam collisions at expermiments mainly lost in the accelerator part adjacent to the experiments).
  • Beam-Gas interaction. (collisions of beam particles with residual gas; gas-density is non-zero in vacuum)

lhc_layout

LHC Sensitive to radiation Areas after R2E Mitigation Program (re-location + shielding) .png

topIrradiation Expected Damages

Electronic devices exposed to radiation can experience 3 different types of radiation damage:

  • T.I.D.    : Total Ionising Dose (cumulative).
  • N.I.E.L. : Non-Ionising Energy Loss (cumulative), 1 MeV equivalent neutron fluence. (Displacement Damage).
  • S.E.E.    : Single Event Effect, proportionnal to High Energy Hardon fluence (with Energies above a few MeV typically 20 MeV), and also depending on the component sensitivity to the Thermal Neutrons (E < 0.5 eV).

A very basic file is provided below with number of equipements per location, giving an estimate of the number of events which can be expected based on the High Energy Hadrons Fluence and each converter sensitivity.

  • TE-EPC LHC Events Irradiation Calculator .xls, and for consultation only .htm

topR2E Mitigation Program

top[2011; 2012] Irradiations Measured Levels

top[2015] Irradiations Measured Levels

top[2016] Irradiations Measured Levels

top[2017; 2018] Irradiations Expected Levels

This period ends up with LS2, where new radiation-tolerant converters will be installed. In 2017-02, FGClite controllers were installed on all LHC60A-08V.
Status and evolution of radiation on 60A power converters, by Ruben Garcia - presented in TE-TM .indico
Update on the expected radiation levels for HL-LHC, by Ruben Garcia - presented in HL-LHC 8th collaboration week in 2018-10-17. .pdf

Area Levels expected for [35; 45] fb-1
Dose [Gy/year] 1MeV
neutrons eq. [nb/(cm.year)]
E>20MeV
hadrons [/(cm.year)]
Th. neutron Ratio [n.th / ..]
Tunnel (ARC MB Cell 12-16)
LHC60A-08V    192 / 750 units
(?) (?) 5E8 3-8
Tunnel (ARC MB Cell 18-34)
LHC60A-08V    556 / 750 units
(?) (?) 1.55E8 3-8
UL14/16
LHC120A-10V           10 units
LHC600A-10V  14+2x1 units
LHC8kA-08V             2 units
LHC6kA-08V             2 units
(2 Inner Triplet systems in total)

<0.5 (?)

(?)

6E6

10-20
RR13/17
LHC120A-10V     36 units
LHC600A-10V     28 units
R2E-LHC6kA-08V     26 units
R2E-LHC4kA-08V     04 units

0.4 (?)

(?)

[2; 4]E8 

1-5
RR53/57
LHC120A-10V     36 units
LHC600A-10V     28 units
LHC6kA-08V     26 units
LHC4kA-08V     04 units

0.4 (?)

(?)

[3; 4]E8 

1-5
RR73/77
LHC120A-10V     20 units
LHC600A-10V     48 units

0.4 (?)

(?)

[1; 3]E7
RR732018:7E7

1-5
UA/J(s), TZ76, UJ33,
 UL55/56, USC55
Some local exception in Point 6
"sea level" expected (Th. n. excepted)

< 0.02

< 4E7

< 1E7

???
Comments
Converters Exposed 1006
Tunnel..... 750
RR13/17.... 94
RR53/57.... 94
RR73/77.... 68
LHC60A-08V....... 750
LHC120A-10V..... 092
LHC600A-10V..... 104
LHC4kA-08V....... 008
LHC6kA-08V....... 052
FGClite controllers are installed in tunnel only.
Exposed 30
UL14/16.... 30
LHC120A-10V...... 10
LHC600A-10V...... 16
LHC6kA-08V........ 02
LHC8kA-08V........ 02
Level is sufficiently low not to upgrade these converters, nor their controllers.

Radiation levels and converters location after LS1

top[2020; 2023] Irradiations Expected Levels

R2E-LHC600A, R2E-HL-LHC600A, R2E-LHC4-6-8kA converters are installed, with FGClite being installed in remaining places (RR1/5/7).

Area Levels expected for [35; 45] fb-1
Dose [Gy/year] 1MeV
neutrons eq. [nb/(cm.year)]
E>20MeV
hadrons [/(cm.year)]
Th. neutron Ratio [n.th / ..]
Tunnel (ARC MB Cell 12-16)
LHC60A-08V    192 / 750 units
(?) (?) 5E8 3-8
Tunnel (ARC MB Cell 18-34)
LHC60A-08V    556 / 750 units
(?) (?) 1.55E8 3-8
UL14/16
LHC120A-10V           10 units
LHC600A-10V  14+2x1 units
LHC8kA-08V             2 units
LHC6kA-08V             2 units
(2 Inner Triplet systems in total)
LHC600A-40V              2 units

<0.5 (?)

(?)

6E6

10-20
RR13/17
LHC120A-10V     36 units
R2E-LHC600A-10V     28 units
R2E-LHC6kA-08V     26 units
R2E-LHC6kA-08V *  04 units
* installed with 5kA DCCT

0.4 (?)

(?)

5E8 TCL-close
5E7 TCL-open

1-5
RR53/57
LHC120A-10V     36 units
R2E-LHC600A-10V     28 units
R2E-LHC6kA-08V     26 units
R2E-LHC6kA-08V *  04 units
* installed with 5kA DCCT

0.4 (?)

(?)

2.5E8 TCL-close
2.5E7 TCL-open

1-5
RR73/77
LHC120A-10V     20 units
R2E-LHC600A-10V     48 units
R2E-HL-LHC600A-10V     02 units

0.4 (?)

(?)

1.4E7

1-5
UA/J(s), TZ76, UJ33,
 UL55/56, USC55
Some local exception in Point 6
"sea level" expected (Th. n. excepted)

< 0.02

< 4E7

< 1E7

???
Comments
Converters Exposed 1008
Tunnel..... 750
RR13/17.... 94
RR53/57.... 94
RR73/77.... 70
LHC60A-08V................... 750
LHC120A-10V.................. 92
R2E-HL-LHC600A-10V.. 002
R2E-LHC600A-10V........ 104
R2E-LHC6kA-08V.......... 060
R2E-LHC600A-10V & R2E-LHC6kA-08V are installed in LS2. FGClite controllers are installed in tunnel and RR1/5/7.
R2E-HL-LHC600A-10V (2) are installed in RR7.
Exposed 32
UL14/16... 32
LHC120A-10V...... 10
LHC600A-10V...... 16
LHC600A-40V...... 02
LHC6kA-08V........ 02
LHC8kA-08V........ 02
LHC600A-40V is now exposed to radiation in UL14/16 (low level still).

Radiation levels and converters location after LS2

top[2025; 2035] Irradiations Expected Levels

HL-LHC upgrade will impact a lot the radiation levels on all sensitive places, since the luminosity will increase from 30 fb-1 to 250 fb-1 per year, for a total of 4 000 fb-1 for HL-LHC era (12 years).

A common factor can very often being used:
1 Gy <=> 1E9 E>20MeV hadrons [/(cm.year)] <=> 1E10 1MeV neutrons eq. [nb/(cm.year)] <=> 1E10 thermal neutrons [nb/(cm.year)]

Area Levels @ Nominal Machine Parameters
Data provided below already include safety margin
Dose [Gy/year] 1MeV
neutrons eq. [nb/(cm.year)]
E>20MeV
hadrons [/(cm.year)]
         Comments         
Tunnel
R2E-HL-LHC60A-10V 72 units 
(072x cell[12;16] Pt1,5,8)

[2; 20] [1E9; 1E10] [1E9; 1E10] Radiation main origin: experience collision debris.
Scaling factor: integrating luminosity.
Pt1,5 Atlas,CMS, pt8 LHCb.
Highly dependant from machine operation mode / optics.
72=3(1,5,8)x3(12,14,16)x4cvsx2sym
Tunnel
LHC60A-08V (678 - 72) units
R2E-HL-LHC60A-08V 72  units
(558x Cell>17)
(120x cell[12;17] Pt2,3,4,6,7)

1.3 1.4E10 2E9 Radiation main origin: interaction of the beam with residual gas.
Scaling factor: integrating intensity, pressure.
72 units, rotation installed qty vs pt1,5,8 units.
RR13/17
R2E-HL-LHC120A-10V 36 units
R2E-HL-LHC120A-10V 12 units
R2E-LHC600A-10V 28 units
R2E-LHC6kA-08V 26 units
R2E-LHC6kA-08V 04 units
* installed with 5kA DCCT
level-0: 08
level-1: 16
level-0: 5E10
level-1: 5E10
level-0: 6E9
level-1: 1E10
Radiation main origin: Atlas collision debris.
Scaling factor: luminosity + TCL. Level-1 (10) considered as level-0 (3) up to 2019-04.
RR53/57
R2E-HL-LHC120A-10V 36 units
R2E-HL-LHC120A-10V 12 units
R2E-LHC600A-10V 28 units
R2E-LHC6kA-08V 26 units
R2E-LHC6kA-08V 04 units
* installed with 5kA DCCT
level-0: 03
level-1: 10
level-0: 5E10
level-1: 5E10
level-0: 3E9
level-1: 7E9
Radiation main origin: CMS collision debris. Scaling factor: luminosity + TCL. Level-1 (10) considered as level-0 (3) up to 2019-04.
RR73/77
R2E-LHC600A-10V 48 units
R2E-HL-LHC120A-10V 20 units
R2E-HL-LHC600A-10V 02 units
0.4 2E8 7E7 Radiation main origin: lost protons in momentum & betatron collimators.
Scaling factor: colimation losses.
UL14/16
R2E-HL-LHC120A-10V 16 units
R2E-LHC600A-10V 02 units
0.01 close to US15/17
0.10 in UL14/16middle
1.00 close to UJ14/16
 2E8 close to US15/17
 1E9 in UL14/16middle
1E10 close to UJ14/16
2E7 close to US15/17
1E8 in UL14/16middle
1E9 close to UJ14/16
High gradient vs location. The R2E-LHC600A is used at 200A. Thermal neutron levels in UJ can be high x10 or x100! E>20 MeV.
UA/J(s), TZ76, UJ33,
 UR15/57
Some local exception in Point 6
"sea level" expected (Th. n. excepted)
0.01 [5E6; 2.5E7] [1; 5]E6 streaming through holes (UA in pt6 to be considered for equipment in line-of-sight or close-by
Comments
Converters Exposed 1028
Tunnel..... 750
RR13/17.... 104
RR53/57.... 104
RR73/77.... 70
UL14/16.... 18
LHC60A-08V................... (678 - n)
R2E-HL-LHC60A-10V.... n (72.min)
R2E-HL-LHC120A-10V.. 116+016 UL14/16
R2E-HL-LHC600A-10V.. 002
R2E-LHC600A-10V........ 104+002 UL14/16
R2E-LHC6kA-08V.......... 060
R2E-LHC600A&kA Power Converters are already in place, since installed in LS2.
HL-LHC120A (92) and R2E-HL-LHC60A (n - 72.min) required converters are installed in LS3 (radiation stress + availability).
Addit. R2E-HL-LHC120A (24) are installed for Q4-Q5-Q6 correctors in RR1/5, with RD2 kA converters removed from RR1/5 (4x in total).
Some converter stays in UL14/16 (LHC600A-40V?)
Infrastructure HL-LHC Creation of UR galleries in point 1/5 IT, allowing installing new converters for HL-LHC Inner Triplet.

HL-LHC radiation level specification document and review @ 2019-12
Last Official R2E-validated Radiation levels @ 2019-09
Update on 60A radiation levels in LHC arc (2019-09 .pdf)
HL-LHC radiation levels in the IP1-IP5 LSS tunnel and RRs, from data here (2019-04 .pdf)
HL-LHC Integration Meeting: ... R2E mapping in DS areas of IR1 and IR5... (2018-11 .pdf)
HL-LHC TCC (2017-11 .pdf)
Informal meeting Yves + Ruben (2018-01-31) in Yves's Office + MCWG (2018-01 .pdf)
6th Annual HiLumi Collaboration Meeting, Paris, November 14-16 2016, from data here (2016-11 .pdf)
R2E Mitigation Levels (after HL-LHC Upgrade foreseen in 2023), from data here (2013-11 .pdf)

topIrradiation Expected Spectra

See following curves detailling the radiation type vs LHC locations (UJ/RR locations dominated by neutrons since shielded, then stopping the protons more efficiently than neutrons) .

lhc_layout lhc_layout lhc_layout

Particle energy spectra (lethargy) and Inverse cumulative high energy hadron fluence for UJ-14/16 & RR-13/17 in the LHC < 2011-12
(more shielded planned to be added in end of 2011).
Curves normalized to a nominal year of operation.

lhc_layout lhc_layout

Particle energy spectra (lethargy) and Inverse cumulative probability plots representative for tunnel areas in the LHC.
Spectra normalized one proton-proton collision (referred to as a primary in the label). Peak seen at lower Ej for the proton fluence due to (n,p) reactions with Nitrogen in air.
Curves normalized to the high Ej hadron fluence.

topReferences

An overview of the radiation environment at the LHC in light of R2E activities .pdf