simulation activities in india: students working on various topics

Simulation activities in India:

students working on various topics..

Partha(VECC), Hemen (GU) : Trigger, SIS100, physics simulation Bipasha (CU): dynamic range simulation, J/Psi physics at FAIR Arun: Geometry study Manish, Irshad (Jammu U)

EVO meet every Thursday: co-ordinator: Z. Ahammed

9th September,2009 CBM-Muon Meeting(EVO) 2

Study of Manual Segmentation of

MuCh

ARUN PRAKASH

High Energy Physics Lab

Department of Physics

Banaras Hindu University

Varanasi-221005


Outline

Manual Segmentation Study

Results

Future Plan

Approach:

Reduce total no of pad sizes to 0.5 Milion

Single track (and muon) efficiency should not change with highest granularity case


Standard Geometry Cbmroot trunk

version Embedded 1000

central events Au+Au at 25 AGeV

Standard MuCh: 13 layers

Total length : 3.4m


Manual Segmentation

A.2x.4 to

1.6 x 3.2

3 regions

Rest all: 1.6 x 1.6

1 region

Total no of pads: 577536


Manual Segmentation(contd...)

B.2 x .4

One region Rest all 1.6 x 1.6 (one region each)

No of pads:No of pads:

12113921211392



C2 regions:

.2 x .4

.4 1.6Rest 1.6 x 1.6.

1 region

No of pads: 628736



D3 regions:

.2 x .4

to.8 x 3.2 Rest:

1.6 x 1.6, one region

Total no of pads: 574464



E3 regions:

.2 x .4 to

1.6 to 3.2

3 regions:

.8 x 1.6 to

3.2 to 3.2

2 regions:

1.6 x 3.2 to

3.2 to 3.2

Rest 3.2 x 3.2

Total no of pads:

195840


Efficiency of Muons(standard geo)Presented earlier

Why no change in efficiency?Can we work with largest pad size?

Take one region/station, double pad size for

every subsequent stationChange track selection criteria and see the effect

Manual Segmentation

STATION PAD SIZE(cm)

1 2 3 4 5 6

A 0.25x0.25 0.45x0.45 0.6x0.6 0.8x0.8 1.25x1.25 1.25x1.25

B 0.5x0.5 0.9x0.9 1.2x1.2 1.6x1.6 1.6x1.6 2.5x2.5

C 1.0x1.0 1.8x1.8 2.4x2.4 3.2x3.2 3.2x3.2 5.0x5.0

D 5.0x5.0 6.0x6.0 7.0x7.0 8.0x8.0 9.0x9.0 10.0x10.0

4 different pad sizesPAD SIZE (1st)PARAMETERS

0.25X0.25(A) 0.5X0.5(B) 1X1(C) 5X5(D)

# of Digis 2210 2191 2060 1113

# of Global track 2335 2401 2925 5130

# of Much Track 1994 2086 2649 4962

(8hits)Eff (STS+MUCH)

0.94 0.94 0.94 0.77

(6hits)Eff(STS+MUCH)

0.84 0.84 0.84 0.73

Eff(10hits)(STS+MUCH)

0.89 0.89 0.89 0.89

Total no of pads 2,400,480 691,040 170,376 15,768


Future Plan

To look into other parameters like invariant

mass, acceptance plot,momentum distribution

etc.

Add clustering

Study auto-segmentation

Dynamic Range of Much

Bipasha BhowmickUniversity of Calcutta, Kolkata

& Partha Pratim Bhaduri,VECC,Kolkata

● DYNAMIC RANGE DYNAMIC RANGE

It is a term used frequently in numerous fields to

describe the ratio between the smallest & largest

possible values of a changeable quantity (such as

measurable deposited energy)

Aim & algorithm

Dynamic range is a quantity essential for design of the read-out chips.

Determination of the energy deposition at each cell of the muon chambers ( in terms of MIP ,as muons give MIP signal).

Take different cell sizes (2mm. – 4cm.) & find out the fraction of multiple-hit cells & singly-hit cells for particles generated by UrQMD.

Optimize the cell size based on multi-hit fraction.

For the optimal cell size find cell energy deposition (E_dep) both for single muons (MIP spectra) & UrQMD particles.

Apply different MIP cuts & calculate the loss due to saturation.

Apply different hit cuts to observe the effect on tracking.

Fraction of multiple-hit cells= (total # of cells having >1 hit)/ (total # of cells hit)

Optimal cell-size : 4mm. for inner stations, 4cm. For outer stations (stn 12 onwards)

Single muon energy deposition spectra :Fitted with Landau distributionMIP value : 0.197 KeV (MPV of the Landau)

Station# 1Cell size : 4mm.

Station# 12Cell size: 4cm.

E_dep by UrQMD particles

Station# 1Cell size : 4mm.

Station# 12Cell size: 4cm.

Saturation loss : part of the energy spectra above the selected energy deposition cut (in terms of MIP) valueMIP cut: E_dep cut (keV)/MIP value(= 0.197 keV)

OBSEVATIONnumber of tracks is affected to a permissible

amount(2.78% of the total tracks) if we reject 2% of

the total hit in each station

• Statistics :

• UrQMD : 50 central events

• Single muons : 50 events with

50 mu+ & 50 mu- in the

momentum range 2.5GeV-

25GeV generated at angle 2.5

to 25 degree using box-

generator

Comparison of percentage of track lost using Comparison of percentage of track lost using

different signals as inputdifferent signals as input

signal-1. hit loss track loss 5% 6.76%

10% 18.55%

signal-2. 5% 7.58%

10% 19.1%

signal-3. 5% 7% 10% 19.16%

Varying the number of muon tracks added in embedding

Trigger simulation

Partha Pratim BhaduriVECC, India

CbmRoot Version: Trunk version

Much geometry : Standard Geometry

• 2 layers in 5 stations

• Distance between layers 10 cm.

• Gap between absorbers 20 cm

• 3 layers at the last trigger station

• Total 13 layers

• Total length of Much 350 cm

Signal : J/ decayed muons from Pluto

Background : minimum bias UrQMD events for Au+ Au at 25 GeV/n

Much Hit producer w/o cluster & avalanche

L1(STS) & Lit (Much) tracking with branching

Input : reconstructed Much hits

Simulation

Absorber thickness (cm):20 20 20 30 35 100

Trigger algorithm

• Take 3 hits from the trigger station with one from each of the 3 layers & fit with st. line both in X-Z & Y-Z plane passing through the origin (0. 0) i.e.

X = m0*Z ; Y=m1*Z Make all possible combinations• Find 2 & apply cut on both 2

X &2y

• Hit combination satisfying the cuts is called a triplet.

• Hits once used for formation of a triplet is not used further.

• Find m0 & m1 of the fitted st. lines

• Define a parameter α=√(m02+m1

2)• Apply cut on α

Magnetic field

(0,0,0)(0,0.0)

11 12 13

Trigger station

Specification of cuts

Cut 1: at least 1 triplet/event

Cut 2 : at least 2 triplets/event

Cut 3 : at least one of the selected triplets satisfy alpha cut

Cut 4 : at least two of the selected triplets satisfy alpha cut

Events analyzed: 80k minimum bias UrQMD event for background suppression factor & 1k embedded minimum bias events for J/ reconstruction efficiency

Event

Input

Cut-1

Cut-2 Cut-3

cut-4

Pluto 10k 7941 2964 2570 1487

UrQMD 80k 2624 255 91 56

Event selection

Set : 1

Cut Values :

2x,y<=0.2

α>=0.183

Background suppression factor (B. S. F)

Cut Events survived

Statistical Error

B. S. F

1 2624 1.95 % ~ 30

2 255 6.26 % ~314

3 91 10.4 % ~879

4 56 13.36 % ~1430

B. S. F = Input events (80,000) / events survived

Reconstructed J/

Trigger cut Reconstruction efficiency (%)

no cut 29.3 %

Cut 1 29.2 %

Cut 2 24.5 %

Cut 3 24.2 %

Cut 4 15.3 %

1k embedded minimum bias events

Trigger Cut 1 (Reconstructed J/ : 292)

Trigger Cut 4 ( Reconstructed J/ : 153)

Observation

• Hit-triplets are made from last 3 layers of the trigger station, vertex included in the fitting.

• Systematic study of background suppression & number of reconstructed J/y & its phase space distribution on cut by cut basis has been done. Statistics will be increased to reduce the statistical error further.

Using information from “Much-only” gives sufficient B. S.F (~1430).

With the application of the 4th trigger cut there is a decrease in signal reconstruction efficiency up to ~ 50 %

Cut by cut investigation shows even up to the 3rd trigger cut we have reasonable B. S. F (~879) but without decrease in signal reconstruction efficiency.

Phase space distribution of the triggered & un-triggered sample shows that all the trigger cuts are unbiased.

Future Plans

Prepare a look-up table for different values of cut parameters &

corresponding values of B. S.F & signal reconstruction efficiency.

Implementation of TRD in the present scheme.

Study pad resolution effect.

Formation of CbmMuchTrigger class to be run in chain.

SIS-100 simulation

We have a HSD version with charm production,

we are running that for generation of signal for

SIS100

Will vary muon geometry (no of stations/pad-

sizes)

Arun (and Dr. Viyogi) will be at GSI working on

this

simulation activities in india: students working on various topics

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