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PSB_BLMS _tests2-3_Daniel

VIEWS: 3 PAGES: 13

									Sensitivity tests of BLM_S
chamber in PSB dump


(Detector for very high radiation
  areas of LHC )

11/5/2006         AB/BI D.Kramer
What is BLM_S

    Low sensitivity BLM pumped to
     approx. 10-5 torr
    Based on Secondary Electron Emission
     from Ti electrode
    Placed mainly in the Collimation areas,
     close to IPs, LHC Dump etc…


11/5/2006            AB/BI D.Kramer
Interior of Secondary
Emission Beam Loss Monitor




11/5/2006   AB/BI D.Kramer
Geant4 Simulation Results
     Secondary Emission Yield
    0.057 e-/primary @ 1.4GeV
Installation in the PSB
dump line




11/5/2006   AB/BI D.Kramer
2005 PSB measurements
                           SEM response linearity check (HV 1000V)

                     460
                     410
                     360
                     310
            counts




                     260
                     210
                     160
                     110
                      60
                      10
                           0       50       100           150      200   250
                                                            10 +
                                         beam intensity [10 p ]

11/5/2006                                AB/BI D.Kramer
Comparison with results from PSI
250MeV continuous proton beam

                                             PSI & PSB SEM voltage scans

                                    20
                                    18
                                    16
            charges / primary [%]




                                    14
                                    12
                                    10
                                     8                                                 PSI positive
                                     6                                                 PSI negative
                                     4                                                 PSB pos.
                                     2
                                     0
                                         0    200   400   600      800       1000   1200   1400       1600
                                                                SEM HV [V]

11/5/2006                                                  AB/BI D.Kramer
                               Modified SEM tested in PSI

                               PSI 19022006 run# 59..68 ~7.108p+/cm2/s SEM F type Transverse + Colimator 10mm
                     35


                     30


                     25
    current [pA]




                     20


                     15


                     10



                     5
                           0         1                                          2                                3
                          10       10                                         10                                10
                                                                  HV [V]




                               PSI 19022006 run# 59..68 ~7.108p+/cm2/s SEM F type Transverse + Colimator 10mm
                     40


                     35


                     30
SEY charges/p+ [%]




                     25


                     20


                     15


                     10


                     5
                           0         1                                          2                                3
                          10       10                                         10                                10
                                                                  HV [V]
2006 Measurements in
PSB dump
    Modified BLMS installed on the movable
     stage 19/4
    1st data taken 4/5 with up to 250e10
     protons/bunch (AD user)
       – maximum intensity allowed by the BLM system
    Access due to HV contact 10/5



11/5/2006                 AB/BI D.Kramer
                                    Linearity of the SEM response in 2006



                               10
                           x 10                       BLMS in PSB dump 4 May 2006 Integration from Scope signal
                      14


                      12


                      10
Secondary electrons




                      8


                      6


                      4


                      2


                      0
                           0                    0.5     1                       1.5                         2     2.5          3
                                                                      Beam intensity [p+/bunch]                            12
                                                                                                                        x 10


                                    11/5/2006                                AB/BI D.Kramer
                                                             BLMS in PSB dump 4 May 2006 Scope signal
                      80
Simultaneous measurement with SEM
                                 and ACEM (PS BLM)
                             equivalent to ~ 1e19 MIPs/s
                                    BLMS & ACEM in PSB dump 4 May 2006 1 bunch of 216*10 10p+
                    180                                                                                  6


                    160
                                                                                                         5
                    140


                    120                                                                                  4




                                                                                                              Current ACEM [mA]
 Current SEM [mA]




                    100
                                                                                                         3
                    80


                    60
                                                                                                         2

                    40

                                                                                                         1
                    20


                      0
                                                                                                         0

                    -20
                      -0.1     0   0.1        0.2        0.3                0.4   0.5       0.6   0.7   0.8
                                                               time [ s]
                                Quench and Damage
                                Levels
                           1.E+18
                           1.E+17                     BLMS* & BLMC                Quench level and observation range
                           1.E+16                                                                               450 GeV
                           1.E+15                                                                                  7 TeV
quench levels [proton/s]




                           1.E+14                          Damage levels
                           1.E+13
                           1.E+12
                           1.E+11
                           1.E+10                                                                                                Dynamic
                           1.E+09                                                                                                Arc: 108
                           1.E+08
                                         Special &
                                                           Arc
                                                                                                                                 Collimator: 1013
                           1.E+07        Collimator
                           1.E+06         1 turn          2.5 ms
                           1.E+05
                           1.E+04
                                1.E-02      1.E-01     1.E+00      1.E+01   1.E+02      1.E+03        1.E+04   1.E+05   1.E+06
                                                                     duration of loss [ms]
                                11/5/2006                                            AB/BI D.Kramer
Summary

    SEY from the first measurements in
     2006: (5 ± 0.3)%
       – Good agreement with 5.7% from Geant4
    No more problems with linearity
    Sufficient time response
    HV scan to be done (we need ~2h
     beam time)
11/5/2006             AB/BI D.Kramer

								
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