4th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino)

Use of multi wires chambers in air for profile measurements of intensive beams

at IHEP (Protvino)

4th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino) 2

Years Proton beam

Neutrino beams

Detector(s) Results

1974 -1982

Up to 2x1012, 30 bunches, 5s spill duration

, anti-

focused beam;beam-dump

ITEP Spark Neutrino Detector

1. -pairs in -interactions;2. search for short-lived particles using nuclear emulsion; 3. tot(N), quasi-elastic scattering,

including limits on -oscillation

parameters, e-scattering, etc.

4. prompt neutrinos (charm production in pFe-interactions)

1985-2003

Up to 1.4x1013 (booster), 29 bunches, 5s spill duration

, anti-

focused beam;beam-dump; short decay path

SKAT Bubble Chamber (up to 1990);  JINR-IHEP Neutrino Calorimeter

1. (anti-)-inclusive scattering, structure functions, e-

universality, exclusive channels2. prompt neutrinos3. e-oscillations with Neutrino Calorimeter

Neutrino beams at IHEP

4th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino) 3

Construction

116 wires

1

2

15

16

VbiasVbias

116 wires

1

2

15

16

Y p

rofile

Beam

3 mm

Vbias

a b c d

1 16

X profile

12

0m

m

15

6m

m

element a and d element b

Mechanical construction of chamber (type A)

4th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino) 4

Construction - 2

Chamber A Chamber B

Signal electrode

Construction 14 central + 2x12 wires connected in parallel, 38mm working area

16 strips, 140mm working area

Material beryllium-bronze alloy aluminum

Size wire of 200 40 x 8mm

Distancebetween wires/strips

0.8mm 1mm

Bias plane 116 wires, 1mm step, beryllium-bronze alloy

116 wires, 1mm step, beryllium-bronze alloy

Distance between signal and bias plane 3mm 3mm

Main parameters of chamber A and B

4th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino) 5

Electronics

ADC +

memory

chamber20m

Schematic drawing

Timing diagram

100s

beam

digitalization

5s 5-10s 5sTime

Signal

4th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino) 6

Measurements (vacuum)

Originally the chambers were used inside of beam pipe under a pressure of ~10-2 torr

Beam profile for focused (chamber A) and wide beam (chamber B)

Channel number

Channel number

16 mm 140 mm

Beam profilesChamber A Chamber B

Number of -electronsNumber of -electrons per proton (measured with Vbias=0):chamber A – 0.03, chamber B – 0.01

4th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino) 7

Measurements (vacuum) - 2

Chamber signal,relative units

1.0•1013

Beam intensity,protons/cm2

Chamber A

Linearity

spill duration varied from 20 ns to 5s

chamber signal is a sum of 14 central wires signals

intensity measured by BCT

Vbias= 0

the same dependency was observed for chamber B too

4th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino) 8

Measurements (vacuum) - 3

Dependence of signal on pressure and bias voltage

chamber signal is a sum of all wires signals

Bias voltage, V

Chamber signal,relative units P ~ 1 Torr

P ~ 2x10-1 Torr

P ~ 5x10-2 Torr

P ~ 5x10-3 Torr

for Vbias=0 the signal is equal for all pressures

after first 1-2 years of use all chambers were operated with Vbias=0

4th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino) 9

The chambers in air

Focused neutrino beam

target

beam~5m ~5-7m

chamber

1985 - 1994

beam-pipe

Short decay path beam

target absorberchamber

beam-pipe

~10m

~ 1996beam

4th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino) 10

Measurements (air)

Linearity

Proton intensity in 1012 protons per spill (5s)

Proton intensity in 1012 protons per spill (5s)

Chamber signal,relative units

Chamber signal,relative units

4th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino) 11

Summary

The multi wires chambers were usefully used during many years in vacuum and air for profile measurements of intensive proton beams.