Torino, October 23-28, 2000

FINUDA @ DANE

PRESENT STATUS AND POSSIBLE UPGRADES

The FINUDA idea;

DANE machine status;

FINUDA detector:

characteristics, performances and

status;

FINUDA possible upgrades!

The FINUDA idea;

DANE machine status;

FINUDA detector:

characteristics, performances and

status;

FINUDA possible upgrades!

FI.NU.DA.FIsica NUcleare a DANE

FI.NU.DA.FIsica NUcleare a DANE

A fixed target experiment carried out at a collider

Main physics ideaMain physics idea

npZZ

nnZZAA

AA

12

2Non-mesonic

decay

ZZK AAstop

High resolution

spectroscopy

High resolution

spectroscopy

low energy (16 MeV)monochromatictagged

low energy (16 MeV)monochromatictagged

Target thickness Very thin (0.1 g/cm2) Thick (some g/cm2)

Resolution onhypernuclear levels ~700 KeV ~1-2 MeV

Acceptance Large (Collider exp.) Small (Fixed target)

Hypernuclei

characteristics

Many hyp. levelsas for (+,K+)

Only substitutionallevels

DANE K- beam K- extracted beams

Projectile momentum Plab (GeV/c)

Hyp

ero

n m

om

entu

m (M

eV

/c)

L= 0o

n

n

p

K- at rest is equivalent to +

K- at rest is equivalent to +

Momentum resolution 1.63 MeV

FWHM

Momentum resolution 1.63 MeV

FWHM

50 cm

Both hypernucleus spectroscopy and hypernucleus decay can be studied in the same experiment

CCK stop1212

pnB 10

Non-mesonicdecay

n

p

Scintillator barrel

neutron detectorLow

mass drift

chambers

Straw tube array

Microvertexsilicon strips

1.1 TeslasolenoidHe bags

K

K

270 MeV/c

KLOECP, CPT violationchiral dynamics... and more

FINUDAHypernuclearphysics

FINUDAHypernuclearphysics

DEARN scattering

(49%)

S

L(34%)

(13%)

Source of monochromatic, collinear and taggable background free neutral and charged kaons

Source of monochromatic, collinear and taggable background free neutral and charged kaons

DANE Hall

DANE Hall

Machine Design ParametersSingle beam energy 0.51 GeV

Horizontal crossing angle 10 – 15 mrad

Beta function @ IP (V/H) 4.5/450 cm

Max num. of particles per bunch 8.9 1010

Beam-beam tune shift (Max)(V/H) 0.04/0.04

bunch legth (r.m.s.) 3 cm

Hor. beam size @ crossing (r.m.s.) 2 mm

Vert. beam size @ crossing (r.m.s.) 20 m

Max number of bunches 120

Ring length 97.69 m

Crossing frequency 368.263 MHz

Machine layoutMachine layout

To get HIGH LUMINOSITY !!n1 n2

xy

L0 = f

1998 In November commissioning was completed with two temporary IR.

1999 At the beginning of the year KLOE and DEARwere rolled-in. The first physics events were observed at IR1 in mid April.1 month of run ~ 2.5 pb-1. Few collision also in IR2 for DEAR.

DANEChronicle

2000 Vacuum accident! After reparation onlymachine development trying to improveluminosity and to reduce background. Main background source is Touscheck effect

Big instabilitiesBeams blow-upL0 = 2·1029cm-2 s-1

L0 = 1030cm-2 s-1

coupling ~ .002%Design param. were achieved

Nlost n2

3 V

Number of particles per bunch

EmittanceRelativistic factorBeam volume

2000 DAFNE Integrated Luminosity

DANE present situationDANE present situation

DANE history 9-10-2000

DANE history 9-10-2000

Single bunch luminosity: L0 = 4·1029cm-2 s-1

Top multibunch luminosity: L = 1.3·1031cm-2 s-1 (with 45 bunches)

Per day luminosity: 200 300 nbarn-1

Collisions are made in only one IR at time.

DANE machine design is similar to PEP-II and KEKB

but

Energy is lower dimension is smaller magnetic latticehas less elements

e.51 GeV 9 GeV 8 GeV

e.51 GeV 3 GeV 3.5 GeV

97.7m 2.2Km 3Km 53 ~450 ~300 quad./ring

DANE perspectivesDANE perspectives

The injection kickers have been rebuild with damping antennas for the offending parasitic modes.

New RF cavities are under study as well as atransverse feedback to cope with instabilities due to the high currents.

Coupling at the IR is under study in order to overcome present limitations on single bunch luminosity.

A lot of work is in progress…A lot of work is in progress…

The FINUDA apparatusThe FINUDA apparatus

Bari University and INFNBrescia University

INFN Frascati National LaboratoriesPavia University and INFN

Torino University, Politecnico, CNR and INFNTrieste University and INFN

TRIUMF VancouverVictoria University

Shahid Beheshty University, TeheranNational Center for Physics, Islamabad

FINUDA DetectorFINUDA Detector

High resolution magnetic spectrometer withcylindrical geometry, optimized for:

• large (~ 2p sr) • good p/p (~ 0.3%)• dedicated Triggers

FINUDA Components

• S.C. solenoid: (r=146 cm, L=211 cm) B = 1.1 T field homogeneous within 2% inside the tracking volume.• Interaction/target region: makes the selection of K+- K- pairs, produces and detects hypernuclei.• External tracking device: measures charged particles trajectories and momenta with high precision.• External scintillator barrel: cooperate to trigger and detect neutrons.• Helium gas chamber: reduce particles multiple scattering.

TOF: (Time Of Flight) 12 NE102A scintillator slabs (200 31 2.3) mm3

topological and dE/dx trigger on () and (e+, e slow down to be stopped in the target time resolution 250 ps FWHM

ISIM & OSIM: (Inner/Outer Silicon Module) double sided 300 m thick microstrip modules spatial resolution 30 m energy resolution 20% FWHM

TARGET: 12C, 6Li thin targets ( 0.1 g cm-2)

BEAM PIPE: Be 400 m thick

/p 408 MeV/c

~ MIP; p ~ 6 MIP

/p 408 MeV/c

~ MIP; p ~ 6 MIP

The Interaction/Target RegionThe Interaction/Target Region

BEAM PIPE

ISIM

OSIMInteraction vertex

TOF

TARGET

5 cm

K

K+

K

K

The Tracking Device

The Tracking Device

e

e

OSIM

LMDC

ST

TOF

Bhabha eventBhabha event

LMDC: (Low Mass Drift Chambers) planar chambers with an He based gas mixture (He-C4H10 70-30) spatial resolutions: (,) 150 m; z 1% wire length

ST: (Straw Tubes) 6 layers of 30 m mylar ST filled with Ar-Eth (50-50) spatial resolutions: (,) 100 m; z = 500 m

TOF: (Time of Flight) 72 scintillator slabs with mainly trigger duties will be used to detect neutron from n.m. decay with efficiency ~ 10 % and energy resolution 8 MeV

2424 straw tubes

= 15 mm,

L = 255 cm

p/p 0.3% FWHMp/p 0.3% FWHMHe atmosphereHe atmosphere

Low Mass Drift Chamber

123 cm

(187 cm)

39

.6 c

m(6

8.6

cm

)Anode wire 3.000.05

Cathode wiresField wire

Cathode wires

Aluminised mylar (12m)

Aluminised mylar (12m)

6.000.05

6.000.05

External mylar (50m)

External mylar (6m)

6.000.05

6.000.05

50.000.03

Drift cell layoutDrift cell layout

Mean resolution of all cells over all angles and over all z

Mean resolution of all cells over all angles and over all z

Straw Tube

Signal/HV cable

Pre-amplifier

Feed-trough assembly

DME Ar+C2H6

50 + 50

Ar+CO2

50 + 50

Max. Lorentz angle (1.1 T)

Negligible Negligible Negligible

Saturated drift

velocity

No Yes Yes

Flammable Yes Yes No

Material ageing Yes No No

HV plateau length (V)

1000 300 50

Space resolution (m)

40 100 150

0

50

100

150

200

250

DME

Loca

l spa

ce re

solu

tion

(mm

)

0

50

100

150

200

250

Ar 50 CO 2 50

0

50

100

150

200

250

0 1 2 3 4 5 6 7 8

Ar 50 Ethane 50

Distance from wire (mm)

-

-

DME

Ar 50 – CO2 50

Ar 50 – Eth 50

The He-gas chamberThe He-gas chamber

The whole tracking volume of FINUDA (8m3) is filled with an Helium atmosphere

FINUDA momentum resolution p/p is:

0.3% in He 1.5% in air

FINUDA momentum resolution p/p is:

0.3% in He 1.5% in air

gas leak avoided by o-ring sealing,adhesive mylar tape and silicone

gas leak avoided by o-ring sealing,adhesive mylar tape and silicone

14

12

10

8

6

4

2

0

He-chamber test

5 10 15 20 25 300time [h]

Oxy

gen

% in

He

PET, PA, PC, EVOHlayers

PET, PA, PC, EVOHlayers

With an He flow rate 900l/hleak rate < 130ml/s

External scintillator barrelExternal scintillator barrel

• Acceptance 29%; • Energy resolution 1.3 MeV at 80 MeV;• Time Of Flight acc. (FWHM) 700 ps

Neutron reconstruction efficiency:

Detection efficiencyDetection efficiency

GeV

Fit = 2.6 MeVEric - Egen

-0.02 -0.01 0 0.01 0.02

160

140

120

100

80

60

40

20

0

Ent

ries

Neutron energy reconstructionNeutron energy reconstruction

Proton reconstruction efficiency:

72 slabs of BC408 mainly used to improve trigger capability

neutron kinetic energy

0 0.05 0.150.1GeV

0

300

100

200

proton kinetic energy

0 0.05 0.150.1GeV

0

70

10

20

30

40

50

60

FINUDA Physics programFINUDA Physics program

Study of non-mesonic decay:- evaluation of p, n

- possibility to select exclusive states 6Li5

He + p - measurement of the energy spectra of non- mesonic decay products

Light hypernuclei mesonic decay study

Energy res. 1.45 MeV FWHM

Energy res. 0.7 MeV FWHM

Measurement of the excitation spectrum withresolution < 1 MeV

C12

High statistic study of p-shell hypernuclei , and (using a 6Li target)

Li 7 Be 9

B10 He 5

FINUDA capabilitiesFINUDA capabilities

This reaction produce the same particles of the n.m channel pnp

but the and the p are emitted back-to-back cutting on angular distribution can be eliminated

main source of backgroung K (np) p n

E ~ 700 KeV

Only forward pionscorrection for energy

lost in the target

Only forward pionscorrection for energy

lost in the target

All pionsAll pions

x

y

10 cm

p

n

g

g

e -

+p p+n non-mesonic decay

+p p+n non-mesonic decay

signal

background 0.6

Main background:

from K+

- without any selection

- selection on

n (candidate) tof

p-n (candidate) angular corr.

p-n (candidate) total energy

signal reduction to 80%background reduction to 2.5%

signal

background 20

n

p

A neutron is anisolated hit notconnected to

charged signals

A neutron is anisolated hit notconnected to

charged signals

x

y

1 0 c m

signal

background 0.17

A neutron is anisolated hit notconnected to

charged signals

A neutron is anisolated hit notconnected to

charged signals

+n n+n non-mesonic decay

+n n+n non-mesonic decay

n

Main background:

from K+

- without any selection

- selection on

n (candidate) tof

n-n (candidate) angular corr.

n-n (candidate) total energy

signal reduction to 93%background reduction to 1.5%

signal

background 11

n

Summary of the FINUDA expected performances @L =

1031 cm-2s-1

Summary of the FINUDA expected performances @L =

1031 cm-2s-1

Hypern

ucl

ear

spect

rosc

op

y

Hypern

ucl

ear

deca

y

Results comparable with the present ones (in a unique data taking)

ground state at 10-3 capture rate

excited state at 2x10-3 capture rate

ground state at 10-3 capture rate

excited state at 2x10-3 capture rate C12

Observable event/hourData

taking timeCollected

events

High resolution

hyp. Spectros.

30 -/htwo states

5103 -

in the spectrum

hyp (tot)2 p/h

in coinc. with -

120 p

p/

proton seen

2 p/hnot in coinc. with neutron

120 p~ 10% error

p/

proton and neutron seen

0.2 (pn)/hp and n coinc.

1 month(~ 10 pb-1)

50 (pn)~ 15% error

n/

2 neutrons seen

0.04 (nn)/h2 neutrons in

coinc.

12 (nn)~ 30% error

n/p ~ 35% error

-/ 40 -

~ 15% error

Summary of the FINUDA expected performances @ L =

1032 cm-2s-1

Summary of the FINUDA expected performances @ L =

1032 cm-2s-1

ground state at 10-3 capture rate

excited state at 2x10-3 capture rate

ground state at 10-3 capture rate

excited state at 2x10-3 capture rate C12

Observable event/ hour Data takingtime

Collectedevents

High resolutionhyp. spectros.

240 htwo states

Less thanone day

(~ 3 pb-1)

1.5x103 in the

spectrum

hyp (tot) 18 p/ hin coinc. with

3x103 p~ 2% error

p/proton seen

18 p/ hnot in coinc.with neutron

One week(~ 50 pb-1) 3x103 p

~ 2% error

p/proton and

neutron seen

2 (pn)/ hp and n in

coincidence1.3x103 (pn)~ 3% error

n/2 neutrons

seen

0.4 (nn)/ h2 neutrons incoincidence

3x102 (nn)~ 6% error

n/p~ 6% error

/1.7 / h

B.R.( ~ 11%

One month(~ 250 pb-1)

1.2x103

~ 3% error

Hypern

ucl

ear

spect

rosc

op

y

Hypern

ucl

ear

deca

y

World class results

FINUDA upgradesFINUDA upgrades

FINUDA is a powerful detector with very good capabilities

low energy kaons can be stopped ~ 100 mg/cm2; big solid angle 4 detectors; best events rate for L ~ 1032 80 ev/h; possibility to study hyp. production and decays; both (K) and (K) are accessible.

low energy kaons can be stopped ~ 100 mg/cm2; big solid angle 4 detectors; best events rate for L ~ 1032 80 ev/h; possibility to study hyp. production and decays; both (K) and (K) are accessible.

The idea of studying hypernuclei on a -factory has many advantages:

high momentum resolution p/p ~ 0.3%; efficient trigger system;

high momentum resolution p/p ~ 0.3%; efficient trigger system;

Upgrades are foreseen to overcome experimental limitation;

Upgrades are foreseen to overcome experimental limitation;

Where is FINUDA main limitation?

The only reasonable upgrade that can be foreseen for FINUDA is to find a good-working-factory

Novosibirsk -factory

Mainz -factory

UCLA -factory

In 1991 at the first DANE workshop 4 –factory

projects were presented together with LNF one

KEK –factory

Only DANE was approved and foundedOnly DANE was approved and founded

“…Strange particles offer us important clues to the nature of matter and the character of the forces that shape the word…”. [C.Quigg-DANE99 workshop summary talk]

If one of those project is still alive or someone is planning to build a –factory we have a very nice detector that can be rolled-in immediately!!

If one of those project is still alive or someone is planning to build a –factory we have a very nice detector that can be rolled-in immediately!!

Circumference 120 m

Num. of bunches 600

Num. of part/bunch 3 1010

Frequency 1.428 GHz

ConclusionsConclusions