Brief Summary of LPA MD - PowerPoint Presentation

Slide1

Brief Summary of LPA MD on 19 June 2012

Jose Abelleira, Xavier Buffat, Chandra Bhat,

Karel

Cornelis

, Riccardo De Maria,

Stephane

Fartoukh

, Rossano Giachino, Eva Barbara Holzer, Mike Lamont, Themis Mastoridis, Alick

Mcpherson

,

Kazuhito

O

hmi

, Giulia Papotti, Tatiana

Pieloni

,

Ferdico

Roncarolo

,

Ghislain

Roy, Belen Salvachua, Daniel Valuch, Frank Zimmermann, …Slide2

started 3.5 hours late (LHC RF crowbar repair, PS 10–MHz cavity),

then 1 h machine set

up; first MD beam injected ~13:45Special hypercycle for Piwinski MD2 bunches of 1.5 e11 per bunch (+pilot), go to collision tunes, & collapsed crossing angles at IP1 and 5, and separation at IP 1,5, and 8; then looked for collisions. Filling scheme with one bunch colliding in IP1,5,and 8, and other bunch colliding in IP 8 only.Impossible to find collisions at ATLAS and CMS, but LHCb could be optimized... decision to dump & re-inject with higher intensity2 bunches of ~2.4e11 injected without separation bump, IP1/IP5 crossing angle at zero, and collision tunes Clear luminosity signals in ATLAS and LHCb No clear Luminosity readings from CMS (some signal towards the end of the MD) ; problem with BSRT data acquisition  LHCb spectrometer ramped down in steps to zero.LHCb spectrometer was left at 0 strength after the MD

MD historySlide3

LPA MD conditions

2.4e11 / bunch; 2 bunches per beam

1st bunch collides in IP 8 only2nd bunch collides in IPs 1, 5 and 8injection energy, 1.5 ns bunch length, e~2 mm ADT off, orbit feedback off, TCTs at coarse settings, IR angle bumps zeroed in IPs 1 and 5 IP8 crossing angle 4 mrad, 2 mrad, 0 (varied with spectrometer strength)collision tunesestimated Piwinski angles ~ 1.1, 0.6, 0largest Piwinski angle ever!Slide4

LPA MD overview

CMS

lumi signal appears at lastATLASlumi signalreduced(steeringeffect)LHCb luminosity signal zero in the databaseSlide5

o

nly short quiet period (30 s?)

at 50% spectrometer strengthLPA MD overview with IP correctorsX. Buffat, T. PieloniSlide6

LPA MD

b

unch intensitiesX. Buffat, T. PieloniSlide7

LPA MD bunch intensities

X.

Buffat100%50%~15%100%50%~15%

bunch with 3 collisions loses much more intensity;

steepest loss at 50% of

LHCb

spectrometer strength;

best lifetime at 0 strength

Jose Abelleira, Chandra Bhat, Xavier

Buffat

,

Karel

Cornelis

,

Riccardo De Maria, Rossano

Giachino,

Mike Lamont, Themis

Mastoridis, Alick

Mcpherson

, Giulia Papotti, Tatiana

Pieloni

,

Ghislain

Roy,

Belen Salvachua, Daniel

Valuch, Frank Zimmermann, + …

q

ualitatively consistent with expectationSlide8

MD simulation by K.

Ohmi

1 day2 hSlide9

EmitX

beam 1

EmitX beam 2EmitY beam 1EmitY beam 217:001.95+/-0.01 mm(1 collision)2.07+/-0.01 mm(3 collisions)2.17+/-0.00 mm(1 collision)2.56+/-0.02 mm(3 collisions)17:172.7+/-0.1 mm(1 collision)2.10+/-0.03 mm(3 collisions)2.0+/-0.1 mm(1 collision)

1.6+/-0.1

m

m

(3

collisions)

2.17+/-0.01

m

m

(1 collision)

1.72+/-0.03

m

m

(3

collisions)

2.11+/-0.01

m

m

(1 collision)

1.64+/-0.01

m

m

(3

collisions)

17:35

2.53+/-0.01

m

m

(1 collision)

2.0+/-0.1

m

m

(3

collisions)

2.01+/-0.01

m

m

(1 collision)

1.56+/-0.02

m

m

(3 collisions)2.11+/-0.04 mm(1 collision)1.67+/-0.02 mm(3 collisions)2.07+/-0.05 mm(1 collision)1.53+/-0.08 mm(3 collisions)

LPA MD bunch emittance

bunch with 3 collisions shrinksSlide10

BBQ

X. Buffat, T.

PieloniSlide11

BBQ Almost fully saturated

X. Buffat, T.

PieloniSlide12

BSRTs

Got stuck on single bunch the one colliding in IP1-5-8…

No apparent reasons for this…X. Buffat, T. PieloniBSRT software had got stuck!?Slide13

R. De Maria

bunch lengthSlide14

Profile MeasurementsApproximate locations

C. BhatSlide15

Bunch 1

Traces:

Bunch Intensity= 2.4E11ppb(2nd Injection)= 0.43 nsec (Gaussian)FWHM=1.00 nsecRelative Area=0.32= 0.45 nsec (Gaussian)FWHM=1.07 nsecRelative Area=0.28Start of the MDEnd of the MDC. BhatSlide16

Bunch 2 Traces:Bunch Intensity= 2.4E11ppb

(2

nd Injection)= 0.42 nsec (Gaussian)FWHM=0.98 nsecRelative Area=0.22= 0.44 nsec (Gaussian)FWHM=1.05 nsecRelative Area=0.14Start of the MDEnd of the MDC. BhatSlide17

plan

r

eview luminosity data from LHCb and CMS (not in logging database)further analysis intensity and luminosity lifetime for different spectrometer strengthsMD note soon – editor Jose Abelleira