Gennaro RuggieroCERN, PH Depart.

Planar Edgeless Detectors for the Planar Edgeless Detectors for the TOTEM ExperimentTOTEM Experiment

On the behalf of theTOTEM Collaboration

http://totem.web.cern.ch/Totem

Total cross-section

Elastic Scattering

jet

jet

Diffraction: soft and hard

b

Forward physics

TOTEM, a different LHC Experiment

Experimental layout of the Experimental layout of the TOTEM DetectorsTOTEM Detectors

Services routing:From Castor to Racks

Patch Panels

T2

Services routing:From Castor to Racks

Patch Panels

T2

Roman Pots at147,220m from the IP

T1

T2

Services routing:

From Castor to Racks

Patch Panels

T2

Services routing:

From Castor to Racks

Patch Panels

T2

T2 CMST1

Inelastics Telescopes

IP5Roman Pots at 147,220m from the IP

Horizontal Pot Vertical Pot BPM

Roman Pot Unit

10σ beam

Detectors overlap in

the data taking position

Special beam insertion allowing to approach the detector very close to the beam. Compensation system allows the movement from garage position (detectors away from the beam) to data taking position (detectors close to the beam) Roman Pot Motion Control integrated with collimator control system Each RP Unit equipped with one BPM

Condition imposed on the Roman Pots Condition imposed on the Roman Pots

•Maximise acceptance at low |t|: edgeless Si-detectorsminimised space between detector edge and windowminimised window thickness•Resolution in t, ; precision of elastic extrapolation to t = 0Spatial detector resolution•Background suppression:trigger segmentationnumber of planes•Redundancyenough planes

The PotThe Pot

Ferrite

500μm

150μm

150μm

The Pot has been object of a specific The Pot has been object of a specific development.development. Is a stainless steel box. Is a stainless steel box. It’s thin It’s thin window 150 μm thick with planarity of 20 μm is window 150 μm thick with planarity of 20 μm is brazed on the bottom of the pot.brazed on the bottom of the pot. It and It and separates the secondary vacuum of the separates the secondary vacuum of the detectors from the vacuum of the machine.detectors from the vacuum of the machine. When the RP is in the Data taking position will When the RP is in the Data taking position will approach the 10σ of the beam .approach the 10σ of the beam .Ferrite plates mounted on the pot to reduce RF Ferrite plates mounted on the pot to reduce RF InterferenceInterference

The PotThe Pot

The detector packageThe detector packagethe “Champignon”the “Champignon”

Vacuum flange

Feed-through

Connectors to detector hybrids

Roman Pot Motherboardconnecting the detector packagesin the vacuum to the outside world

In each pot 5 u and 5 v oriented planes are inserted in form of a detector package. The plane-hybrid is made of kapton laminating a support plate of CE07 (70% Si and 30% Al alloy) which matches the thermal expansion of the silicon detector. The flexible pigtail guarantees a mechanical decoupling of the detector package from the “champignon” to align on the pot inner surface.

VFAT chis

Si microstrip detector

Commissioning of the pots in H8 with muonsCommissioning of the pots in H8 with muons

V-coordinate U-coordinate

All 8 Roman Pots Units Installed in the LHCAll 8 Roman Pots Units Installed in the LHC

… few weeks ago

First 2 Roman Pots Detector PackagesFirst 2 Roman Pots Detector Packages

… few months ago

The sensor: Edgeless DetectorThe sensor: Edgeless Detector

Edgeless? How does it work…

But if…But if…Surface Current SuppressionSurface Current Suppression

Standard Planar Silicon detectors have an edge.Standard Planar Silicon detectors have an edge.

IBE

ICTR +ICR

Developed by: CERN/PH-TOT, Ioffe PTI- St. Petersburg, RIMST- Zelenograd

EDGELESS DETECTORS with Current Terminating Structure

•Protective structure at the edges•Enhancement of the performance at higher bias•Reduction of surface effects

•Wide dead volume at the edge (>2d)

Voltage terminating ringsV=0V=Vb

n+p+

Voltage terminating ringsV=0V=Vb

n+p+

>2dd

Very High Resistivity Si n-type <111>, 300um thick, Vdep=20VVery High Resistivity Si n-type <111>, 300um thick, Vdep=20V Standard planar technology fabrication / dicing with diamond sawStandard planar technology fabrication / dicing with diamond saw Single sided detector, 512 microstrips (pitch 66um)Single sided detector, 512 microstrips (pitch 66um) strips at 45° from the sensitive edgestrips at 45° from the sensitive edge AC coupled (punch-through)AC coupled (punch-through)

Roman Pot Si Edgeless detectorRoman Pot Si Edgeless detector

Pitch adapter on detector (VFAT / APV25 compatible)

100nA

1µA

10µA

100µA

Cur

rent

, A

200150100500

Bias, V

current_A2_BR current_A2_CTR

Measurement of leakage (bulk) current Measurement of leakage (bulk) current 70 nA at 200 V70 nA at 200 V

performance at the edgeperformance at the edge•Testbeam with muons (cern, X5) •4 prototypes of RP Detectors Packages with APV 25 chip•Packages (mis)aligned along the beam axis • The whole hosted in a coldbox for a ( Tsensor= -10°C)

Detector Package (6 tracking and 2 trigger planes) Orientation and overlapping of the 4 detector packages optimized two study the edges on the two internal packages

Telescope arrangementTelescope arrangement

The “monster” coldbox

13

4 2

65(z)

Signal in EdgelessSignal in Edgeless detector detectorss, 100 V, 100 V

Voltage scanSignal-to-noise distribution

Beam profile

Efficiency and resolutionEfficiency and resolution

*bins are 0.5 x 0.5 mm2

Top test detectorBottom test detector

Efficiency at the edgeEfficiency at the edge Residual profileResidual profileStrip charge sharing mapStrip charge sharing map

Accepted tracks in the test detectors

Radiation hardness?Radiation hardness?1.0

0.8

0.6

0.4

0.2

Effi

cien

cy500400300200100

Bias Voltage, V

1*1013pcm-2

5*1013pcm-2

1.4*1014pcm-2

600

500

400

300

200

100Sur

face

Cur

rent

, µA

20151050

fluence, 10^13 n cm-2

All detectors biased at 100 V

Surface current

150

100

50

0Bul

k C

urre

nt a

t ful

l dep

letio

n, µ

A

1086420

fluence, 10^13 n cm-2

Bulk current I∝*Φ

Test samples 1cm2 / 1MeV neutrons

Real devices/ 24 GeV protons

-117 Acm105

At the tested fluences these edgeless detectors seem to behave as standard pAt the tested fluences these edgeless detectors seem to behave as standard p++-n strip detectors -n strip detectors

Data from a recent test beam (muons, H8) comparing hits with a non irradiated detector superposed on the beam axis

Radiation harder?Radiation harder?Further studies on radiation hardness are ongoing. Further studies on radiation hardness are ongoing.

Lately a Consortium under INTAS umbrella (groups from Lately a Consortium under INTAS umbrella (groups from Barcelona Barcelona CNM, University of Bologna, CERN, Lappeenranta TU, Ioffe St. CNM, University of Bologna, CERN, Lappeenranta TU, Ioffe St. Petersburg, RIMST ZelenogradPetersburg, RIMST Zelenograd) has joined together to mainly address ) has joined together to mainly address radiation issues for Planar Edgeless Detectors with CTS (radiation issues for Planar Edgeless Detectors with CTS (TOSTER TOSTER ProjectProject).).

•Study of electric field at the edge with differt experimental testsStudy of electric field at the edge with differt experimental tests•Test of different cut techniquesTest of different cut techniques•Simulations of the detector behaviour starting from the data Simulations of the detector behaviour starting from the data acquired acquired •Extrapolation at high doseExtrapolation at high dose•Design optimizationDesign optimization(Part of the story can be read at the poster by E. Verbitaskaya)(Part of the story can be read at the poster by E. Verbitaskaya)

Fabrication of Edgeless detectors with Czochralski material, with an Fabrication of Edgeless detectors with Czochralski material, with an adapted CTS designadapted CTS design

We will see…We will see…