![Page 1: LHC BI 2015 Summary: BSRL M. Palm (BE-BI-PM) 2015-11-12 1](https://reader031.vdocuments.us/reader031/viewer/2022012914/5a4d1ade7f8b9ab059975e68/html5/thumbnails/1.jpg)
1
LHC BI 2015 Summary: BSRLM. Palm (BE-BI-PM)
2015-11-12
![Page 2: LHC BI 2015 Summary: BSRL M. Palm (BE-BI-PM) 2015-11-12 1](https://reader031.vdocuments.us/reader031/viewer/2022012914/5a4d1ade7f8b9ab059975e68/html5/thumbnails/2.jpg)
2
Changes since Run 1Optical line• BSRL and BSRA on
extension table
Hybrid detectors installed• Both beams since TS2
TS3• Hybrid shutter control
installed• Additional layer of protection
against saturation
2015-11-12
APD
• IRF widens at shorter wavelengths
•Filter Better signal at high energies
Color filter (APD)
Synchrotron light
•Fiber-coupled sub-ns pulsed laser installed in gallery
•SPAD afterpulse calibration
•System functionality verification
Pulsed laser
• Reduce impact (signal variation) of extraction mirror movement
Diffuser (APD)
•Replacing filter wheels
•5 filters (Attenuation up to ~107)
Neutral density filters
BSRA
•Block reflections
Screens
Hybrid
![Page 3: LHC BI 2015 Summary: BSRL M. Palm (BE-BI-PM) 2015-11-12 1](https://reader031.vdocuments.us/reader031/viewer/2022012914/5a4d1ade7f8b9ab059975e68/html5/thumbnails/3.jpg)
APD: Performance
2015-11-12 3
Distorted bunch profile
“Phantom” bunches
“Phantom” bunch signal typically decreases
during the fill
Mechanism not fully understood…•Possible cause: bias voltage ripple (>GHz) leading to sensitivity fluctuations and avalanche onset.
![Page 4: LHC BI 2015 Summary: BSRL M. Palm (BE-BI-PM) 2015-11-12 1](https://reader031.vdocuments.us/reader031/viewer/2022012914/5a4d1ade7f8b9ab059975e68/html5/thumbnails/4.jpg)
Hybrid: Intended use (1)
2015-11-12 4
Doublets
Satellites
Doublet train, B1 (Fill 4164)
Satellite fraction (
Ghost fraction (
vdM-scan: Ghost & Satellite fraction
Hybrid significantly
better than APD
Flattop
![Page 5: LHC BI 2015 Summary: BSRL M. Palm (BE-BI-PM) 2015-11-12 1](https://reader031.vdocuments.us/reader031/viewer/2022012914/5a4d1ade7f8b9ab059975e68/html5/thumbnails/5.jpg)
5
Hybrid: Intended use (2)
2015-11-12
B1 Satellite & Ghost map (vdM scan, Aug 25)
=Filled/masked bucketAbort Gap
![Page 6: LHC BI 2015 Summary: BSRL M. Palm (BE-BI-PM) 2015-11-12 1](https://reader031.vdocuments.us/reader031/viewer/2022012914/5a4d1ade7f8b9ab059975e68/html5/thumbnails/6.jpg)
6
Hybrid: Bonus
2015-11-12
Abort gap population Synchronous phase shift, Bunch by bunch
![Page 7: LHC BI 2015 Summary: BSRL M. Palm (BE-BI-PM) 2015-11-12 1](https://reader031.vdocuments.us/reader031/viewer/2022012914/5a4d1ade7f8b9ab059975e68/html5/thumbnails/7.jpg)
7
(No baseline subtraction)
RawBeam loss correction
Hybrid: Unexpected
• Most likely beam losses(?)
• Bunched signal from wrong beam corrupts measurement
• …can be corrected• Long term damage?
Profile of opposite beam is detected
2015-11-12
B1 structure seen by B2 hybrid
![Page 8: LHC BI 2015 Summary: BSRL M. Palm (BE-BI-PM) 2015-11-12 1](https://reader031.vdocuments.us/reader031/viewer/2022012914/5a4d1ade7f8b9ab059975e68/html5/thumbnails/8.jpg)
8
Outlook
• Install BSRL equipment on removable breadboard
YETS
• Investigate BSRL installation in UA• Less exposed to radiation• Two complementary systems in RA
and UA• Issues:
• Broad-band light signal through 75 m fibre => Severe dispersion
• 2’’ light cone into ~10s m fibre• Scintillation?
2016
2015-11-12
Current location
New location?
Fibre
![Page 9: LHC BI 2015 Summary: BSRL M. Palm (BE-BI-PM) 2015-11-12 1](https://reader031.vdocuments.us/reader031/viewer/2022012914/5a4d1ade7f8b9ab059975e68/html5/thumbnails/9.jpg)
9
Backup
2015-11-12
Hybrid abort gap estimate and measured beam loss