pnpi, r&d much related activity ● segmentation ● simulation of the neutral background...

PNPI, R&D MUCH related activity

● Segmentation ● Simulation of the neutral background influence● R&D of the detectors for MUCH ● Preparation to the beam test

A.Khanzadeev_GSI_April 2010

It was considered 10 variants of segmentation for 5 stations (each of them has 3 detecting layers):1. Monolithic GEM design (no dead zones)2. Module GEM design with modules of 25.6x25.6 cm2 each3. Module GEM design with modules of 51.2x51.2 cm2 each

Segmentation (E.Kryshen, M,Ryzhinski)


First station in case of monolithic design (left), case of modules 25.6X25.6 cm2, and case of modules 51.2x51.2 cm2 (right).

Each variant of segmentation was tested for ω→µµ

Pad size 2x2 mm2Pad size 4x4 mm2


Gap between absorbers 30 cm

Station 4 in case of:Modules of straw (left), blue lines – one dimension straw hitsGEM modules 25.6x25.6 cm2 (right), points – 2D GEM hits


In the calculations:

■ compact MUCH

■ ω→µµ process

■ realistic hit producer

■ different thresholds for hit recognition

■ realistic detectors geometry (different variants of segmentation, realistic geometry of detecting layers, dead zones, and so on)

Threshold for hit recognition


Monolith

Modules 51.2x51.2 cm2

12

9

10

16

17

1 2 3 4 5

67 8 11

15

14

16

18

13

FEE layout for the central area of Station 1

Sketch represents our current understanding

Realistic pad layout by E.Kryshen and M.Ryzhinsky, pad size: 2*2 mm.Box represents FEE card of 512 channels + HUB and optical fiber interface.

V.Nikulin


• Power consumption: 5W (xyter) + ? ROC i.e. ~6W(?) per card or 3*430W in central area size of 50*50 cm.

• Thermal analysis is required• Heat sink size: 30*40 mm;• Type of the heat sink should be chosen (water/air or

something else)• Additional transverse size of the chamber should be

taken into account


GEANT4 study of neutral background in CBM MUCH detector for Helium and Argon as two alternative working gas options. Victor Baublis, PNPI, March 2010e-mail: [email protected]

Layout of simulated setup

Simulation was performed for simplified detector prototype consisting only from gas volume, FR-4/G10 construction walls and Ar/He gases

5 mm

2 mm


Origin vertex z coordinate distributions of the charged secondary particles which were produced inside the detector-prototype by the beam neutrons and photons.

■ For both options of working gas the contribution of the FR-4 walls in neutron and photon hit rate dominates

■ The hit rate of neutrons does not exceed 10% from the hit rate of photons

■ Total hit rate of neutral particles in the Argon is about 10% higher than in Helium

Some results of the simulation


This year our main R&D activity – assembling and testing two prototypes. One of them – Double TGEM, another one – hybrid MICROMEGAS/GEM

Anode structure2048 pads with hidden contact holesPad size 1.5x 3 mm2

Working area 102x109 mm2

Gap between pads 0.2 mm

Preamp to take signals from mesh or TGEM


R&D of the tracking detector for MUCH

Double TGEM1/TGEM2

Ar/CO2/iC4H10 (90/8/2)

GG vs. ΔVg1&ΔVg2 (ΔVg1=ΔVg2) (ΔVag=300V, ΔVg1g2=300V, ΔVcg=800V)

GG

x10

3

TGEM1, TGEM2 are identical:

thickness – 0.53 mm

step between holes – 1 mm

hole diam.– 0.6 mm

rim diam.- 0.74 mm

volts


For double TGEM1/TGEM2 we can reach Gas Gain up to 30∙103 and energy resolution fwhm ~30% without visible problems

Gaps:

Anode-G1 – 1.5mm

G1-G2 – 1.5 mm

Cathode-G2 – 4 mm

The best energy resolution reached was 29% (fwhm)

Double TGEM1/TGEM2


volts

Gas

gai

n X

103

GG vs. ΔVg1&ΔVg2 (ΔVg1=ΔVg2) (ΔVag=300V, ΔVg1g2=300V, ΔVcg=800V – fixed)

He/CF4/iC4H10 (75/23/2)

During the test with 55Fe double TGEM detector showed stable behaviour. Operation of the detector with He based gas mixture allows soft HV regime to get supposed for MUCH electronics value of GG=2∙104

Micromegas/GEM

Energy resolution fwhm~36%

3.7 mm

2.6 mm

60 mcm

Ar/CO2/iC4H10 (90/8/2)

GEM – produced by CERN PCB has hidden contact holes

GG vs. Vm&ΔVg (Vm=ΔVg) (ΔVmg=100V and 250V, ΔVcg=350V – fixed)

Easy to get GG ~4∙105

We are taking signals from the mesh


He/CF4/iC4H10 (75/23/2)Micromegas/GEM

GG vs. Vm(ΔVmg=50V, ΔVg=ΔVcg=0V – fixed)

GG vs. ΔVg (Vm=400V, ΔVmg=260V, ΔVcg=400V – fixed)

GG vs. Vm&ΔVg (Vm=ΔVg) (ΔVmg=260V, ΔVcg=400V – fixed)

During the test with 55Fe Micromegas/GEM detector showed stable behaviour. Operation of the detector with He based gas mixture allows very soft HV regime to get supposed for MUCH electronics value of GG=2∙104. It is enough to keep 320-330 volts on Gem and 320-330 volts on Micromegas


Easy to get GG ~4∙105

Plans for this year

■ Continue work on segmentation

■ Make beam test of the prepared prototypes


pnpi, r&d much related activity ● segmentation ● simulation of the neutral background...

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