Results of the 2007 BLM hardware tests in LSS5
Daniel Kramer for the BLM team
..And a coast MD request for the 2008
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Standard BLMI Standard BLMI ARCARC installationinstallation
HV Power Supply
HV ground cut here
BLMI
Up to 8 BLMs connected in parallel
CFC is always close to the quadrupole
Small low pass filter in the CFC input stage
BLMICFC
280pF
0.47u
10MCBH501M 470 2k2
4n7COAX < 30m
integrator
8X
CBH50
BJBHT1.5kV
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BLMI installation for collimation BLMI installation for collimation areasareas
6 HV capacitors in parallel
HV capacitor removed
150k for current limitation
280pF = chamber’s capacity
8 chambers in 1 NG18 cable (up to 700m)
BJBAP
BLMICFC
280pF
CBH501M 470 2k2
4n7
COAX < 30m
integrator
8X
CBH50
BJBHT1.5kV NG18 < 700m
150k
BJBHT
2u8
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SPS LSS5 Installation – SPS LSS5 Installation – System ASystem A
• study space charge effects with large doses
•Compare directly BLMI with SEM
AIM:
• large capacitor directly on the HV side
• Cf capacitor directly on the signal side
• 150kOhm after Cf -> large time constant
BJBAP
BLMICFC
280pF
CBH501M 470 2k2
4n7
integrator
8X
CBH50
BJBHT1.5kVNG18 ~ 200mBJBHT
2u8
Cf
150k
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SPS LSS5 Installation – SPS LSS5 Installation – System BSystem B
• study cable crosstalks with different filters
• verify the peak current limitation by the 150k resistor
AIM:
• Cf capacitor directly on the signal side
• 150kOhm on HV side -> current limitation
BJBAP
BLMICFC
280pF
CBH501M 470 2k2
4n7
integrator
8X
CBH50
BJBHT1.5kVNG18 ~ 200mBJBHT
2u8
Cf
150k
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BLM installationBLM installationin LSS5 of SPSin LSS5 of SPS
Beam
Collimator
BL 2
51934
BL 3
BL 4 BL 5
Q 52110 MB
BL1
SEM 1
MB 52150
Q 52010
BL 2ABL 1A
BL 5ABL 4A
BL 3A
MB
SEM 2
System A
System B
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Beam dump on Closed JawsBeam dump on Closed JawsSEM to BLMI comparison 1.3 SEM to BLMI comparison 1.3 10101313pp++
Black line – signal not clipped
5*τ_filter = 350ms
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BLMI Space charge effect BLMI Space charge effect estimation (“signal saturation”)estimation (“signal saturation”)
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BLMI Space charge effect BLMI Space charge effect estimation (“signal saturation”)estimation (“signal saturation”)
SEM expected to be “saturation free”
BLMI’s expected deposited dose to be scaled by SEM/BLMI ratio from FLUKA (50%
errorbarx)
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150kOhm resistor limitation150kOhm resistor limitation(between HV capacitor & IC)(between HV capacitor & IC)
Limits the peak current on the chamber input to Limits the peak current on the chamber input to 1500 / 150k = 10mA 1500 / 150k = 10mA
Fast loss has only the Chamber charge Fast loss has only the Chamber charge available 280pF * 1500V = 0.4 uCavailable 280pF * 1500V = 0.4 uC
– Corresponds to ~ 7 mGy total lossCorresponds to ~ 7 mGy total loss
– Corresponds to ~ 180 Gy/s (PM limit = 22 Gy/s..)Corresponds to ~ 180 Gy/s (PM limit = 22 Gy/s..)
Slows down the signal collectionSlows down the signal collection
DC current limited to 1500 / 1M = 1.5 mADC current limited to 1500 / 1M = 1.5 mA
– Corresponds to ~ 26 Gy/s (total in max 8 chambers)Corresponds to ~ 26 Gy/s (total in max 8 chambers)
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Cable crosstalks studyCable crosstalks studySystem ASystem A
Ch 8 Ch 8 unconnectedunconnected
Ch 2 saturatedCh 2 saturated Xtalk should Xtalk should
be be proportional to proportional to the signal the signal derivationderivation
Signal peak Signal peak ratio 4.3e-3 ratio 4.3e-3 (47dB)(47dB)
Integral ratio Integral ratio 1.4e-4 (77dB)1.4e-4 (77dB)
0 0.1 0.2 0.3 0.4 0.5 0.6 0.70
1
2
3
4
5
6
7Xtalk CD1 - A
time [ms]
coun
ts
CH8
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7-50
0
50
100
150
200
250Differential signals of CD1 - A
time [ms]
diffe
renc
es [c
ount
s]
CH1CH2CH3CH4CH5CH6CH7
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Cable crosstalks studyCable crosstalks studySystem BSystem B
Ch 6..8 unconnectedCh 6..8 unconnected Xtalk clearly Xtalk clearly
depends on the depends on the derivationderivation
Signal peak ratio Signal peak ratio 5e-2 (26dB) (worst 5e-2 (26dB) (worst case)case)
Integral ratio Integral ratio 4.4e-3 (47dB)4.4e-3 (47dB)
No fundamental No fundamental difference between difference between A and B A and B
0 0.1 0.2 0.3 0.4 0.5 0.6 0.70
5
10
15Xtalks CD3 - B
time [ms]
coun
ts
CH6CH7CH8
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7-20
0
20
40
60Differential signals of CD3 - B
time [ms]
diffe
renc
es [c
ount
s]
CH1CH2CH3
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Resulting actions for the LHC Resulting actions for the LHC installationinstallation
HV cables separated between SEM and HV cables separated between SEM and BLMIBLMI
Signal cables (NG18) not shared by SEM Signal cables (NG18) not shared by SEM and BLMIand BLMI
CFC cards not shared eitherCFC cards not shared either
For collimation areasFor collimation areas
– capacitors removed from the chamberscapacitors removed from the chambers
– 150kOhm resistance to limit the i/o BLMI 150kOhm resistance to limit the i/o BLMI currentcurrent
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System ASystem A 1.3e13 p 1.3e13 p++ dumped on collimator, dumped on collimator,Left Jaw at -5 mm, Right Jaw outLeft Jaw at -5 mm, Right Jaw out
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System ASystem A 1.3e13 p 1.3e13 p++ injection plateau, injection plateau,Left Jaw at 10mm, Right Jaw out, Dump @ Left Jaw at 10mm, Right Jaw out, Dump @ 1.2s1.2s
FFT of the FFT of the previous plot previous plot (red channel (red channel from 200 to from 200 to 1200ms)1200ms)
Different scales Different scales presentedpresented
The 3-phase power supply The 3-phase power supply lines similar to the coasting lines similar to the coasting case. 600Hz should be case. 600Hz should be caused by the 12-pole caused by the 12-pole converter of the rectifierconverter of the rectifier
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Jaw not closed: comparison of system Jaw not closed: comparison of system A and BA and B
Sys B
Sys A
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MD request for 2008MD request for 2008
2007 halo oscillations estimated to ~1.8 um2007 halo oscillations estimated to ~1.8 um Aim is to verify the beam halo position Aim is to verify the beam halo position
oscillations oscillations – by using both horizontal jaws (LHC collimator)by using both horizontal jaws (LHC collimator)
– By using vertical jaws of the SPS collimatorBy using vertical jaws of the SPS collimator
– Is the beam center moving? (fast BPMs)Is the beam center moving? (fast BPMs)
Need Need – coasting beam 270 GeVcoasting beam 270 GeV
– Up to 12 bunchesUp to 12 bunches
– LHC Collimator controlLHC Collimator control
– SPS Collimator control SPS Collimator control
2006 data
CWG 19/3/07
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W37 Coasting beam 270GeV W37 Coasting beam 270GeV 200um Left jaw move, no signal 200um Left jaw move, no signal filtersfilters
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W37 Coasting beam 270GeV W37 Coasting beam 270GeV 200um Left jaw move, no signal 200um Left jaw move, no signal filtersfilters
thanksthanks
Spare plots 1 Tune calculation from the BLM Spare plots 1 Tune calculation from the BLM measurementmeasurement
Spare plots 2 Spare plots 2 H4 Calibration of the SEM (to be presented H4 Calibration of the SEM (to be presented later)later)
Spare plots 3Spare plots 3 SEM assemblySEM assembly