SIMULATION OF A SIGNAL IN THE BEAM LOSS

Transcription

1 RADIATION ASPECTS OF LHC SIMULATION OF A SIGNAL IN THE BEAM LOSS MONITORS OF THE MOMENTUM CLEANING INSERTION FOR THE NEW COLLIMATOR JAWS DESIGN IHEP, Protvino, Russia

2 Summary of the presentation Page 1 Introduction Initial setup Simulation strategy Results and discussion Conclusion

3 Introduction: Beam Loss Monitor Page Previous studies (Al + Cu) a definition of the BLM model the main features of the BLM signal formation in the momentum cleaning a signal sensitivity to optics, geometry (layout), materials Goal of the study (C + C) simulation of a signal the BLMs located in the IR3 insertion for the collimators made of the double density carbon

4 -5 5 Initial setup: shielding design Page 3 Layout of one half of the momentum cleaning section Q6L DL D3L Q5L QL TCS6_ TCS_ TCS5_ TCS_ TCS3_ Ring Ring 1 TCS1 TCP z, m y, cm

5 Initial setup: details Magnet optics - version V6. Reduced shielding design New design of the collimator jaws Carbon of double density for TCP and TCS Injection - n = 6, n = 7 Top energy - n = 1, n = Injection Collision Collimator Length skew angle radius skew angle radius (cm) (mrad) (cm) (mrad) (cm) TCP TCS TCS TCS TCS TCS TCS Page

6 Initial setup: details Page 5 Collimator Shielding Position of the BLM 3 cm downstream of TC The primary losses are shared between 1 primary and 6 secondary collimators for each ring. Ring The relative rates of inelastic interactions in the collimator jaws. T C S Ring 1 B L M z, cm Collimator Injection Collision TCP1.668(.31).87(.76) TCS1.1(.11).(.59) TCS.91(.183).56(.78) TCS3.53(.1).3(.5) TCS.(.3).11(.) TCS5.(.3).11(.) TCS6.6(.7).3(.5) y, cm

7 !! $% " ' & Page 6 Simulation strategy The K code a map of pr.in.int.(5 protons) BLM - an air ionisation chamber (1x1x1 cm ) Simulation approaches (1) () B L M (3) () #" The MARS code the fluence and energy deposition simulation Energy thresholds - 1 MeV for charged hadrons, 1 MeV for electrons An individual cascade from inelastic interactions inside the jaws of each collimator (j) impacting on BLM y, cm pr.in.int./run) 1 (i) is simulated separately ( 1. x, cm

8 ! Page 7 Simulation strategy: a few theory (5) (6) (7) (8) Case A (ideal) (9) (1) (11) (1) (13) (1) & ) and Case B (no uncertainties! ) and Case C (uncertainties!

9 Page 8 Results: the response of the BLM ) of the beam loss monitors per one lost inelastic proton on each The responses (cm collimator at top energy Beam loss monitor Collimator (j) (i) TCP1(1) TCS1() TCS(3) TCS3() TCS(5) TCS5(6) TCS6(7) BLM BLM BLM BLM BLM BLM BLM

10 Page 9 Results: the response of the BLM The ratio of fluence of charged particles for collimators (C) to fluence for collimators (Al + Cu) per one lost inelastic proton at top energy Beam loss monitor Collimator (j) (i) TCP1(1) TCS1() TCS(3) TCS3() TCS(5) TCS5(6) TCS6(7) BLM BLM BLM BLM BLM BLM BLM

11 Page 1 Results: the response of the BLM ) of the beam loss monitors per one lost inelastic proton on GeV ' The responses (1 each collimator at top energy Beam loss monitor Collimator (j) (i) TCP1(1) TCS1() TCS(3) TCS3() TCS(5) TCS5(6) TCS6(7) BLM BLM BLM BLM BLM BLM BLM

12 Results: good signal... Page 11 Formation of a good signal and background signal in the BLMs Collimator Shielding Collimator Shielding Ring TCS TCS3 Ring 1 BLM BLM z, cm y, cm

13 ' ' Page 1 Results: partial signal at top energy Partial signal Size of the good signal cm GeV BLM1 1. cm BLM Collimator GeV BLM7 1.7 /s s Size of the total signal cm GeV Min (BLM1) 1. cm GeV Max (BLM) 1. Signal, GeV cm -3

14 Page 13 Results: ratio at top energy BLM Collimator BLM1 good spatial resolution (1%) BLM3 (close to TCS) only 57.% Good signal BLM % BLM 9% BLM5 5% BLM6 % BLM7 1% TCP1 - major contributor to background BLM 96% BLM7 % Ratio

15 $ & $ & Page 1 Results: signal from Ring??? Estimation BLM number 1-6 Case A % BLM3 Case B Good signal 1% BLM BLM number Signal, GeV*cm -3 Signal, GeV*cm -3

16 $ & $ & $ & $ & $ & $ & Page 15 Results: signal from Ring BLM position - left margin (side) Case A 1% BLM5-BLM BLM number Case B Good signal 37% 67% 15% 83% 75% BLM BLM BLM5 BLM6 BLM BLM number Signal, GeV*cm -3 Signal, GeV*cm -3

17 $ & Page 16 Results: signal from Ring Mistuning of the TCP1 All primary halo on TCS1 (no TCP1) 1% BLM Collimator BLM1 Ratio

18 & Results: correlations at top energy??? Page 17 BLM Collimator Collimator Collimator Ratio Ratio Signal (BLM) Energy deposition (jaws)?

19 BLM7 1.5 Page 18 Results: the response of the BLM ) of the beam loss monitors per one lost inelastic proton on each The responses (GeV collimator at injection Beam loss monitor Collimator (j) (i) TCP1(1) TCS1() TCS(3) TCS3() TCS(5) TCS5(6) TCS6(7) '.11 ' ' ' BLM1 BLM BLM3 BLM BLM5 BLM ' ' ' ' '

20 Page 19 Results: partial signal at injection Partial signal Size of the good signal cm GeV BLM 5.8 cm BLM Collimator GeV BLM /s s Size of the total signal cm GeV Min (BLM7) 5.7 cm GeV Max (BLM) 7.7 Signal, GeV cm -3

21 Page Results: ratio at injection BLM Collimator Good spatial resolution BLM1 1%..1 BLM 75% BLM3 99% Good signal BLM 9% BLM5 % BLM6 31% BLM7 1% Major background adjacent collimator Ratio

22 Conclusions Page 1 Good signal is less than before, the background is more The response matrix has a triangular form only for Ring1 The response matrix depends on impact parameters, layout (collimator + beam pipe + BLM + shielding), the BLM position and Z material. At top energy, the BLM1 has the good spatial resolution. At injection, the BLM1-BLM3 have the good spatial resolution. At top energy, the TCP1 is a major source of background in the BLMs (96% for BLM) Background signal from the Ring depends on the BLM position. It does not exceed 1% (BLM3) in the case of the total. Background comes to 1% (BLM7) in the case of the good signal. Background from the Ring can exceed size of signal from Ring 1 more than in 7 times Correlation between partial energy deposition in the collimator jaws and the partial signals in the beam loss monitors Actually, the dependence of a signal is more complex (see case C)