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)Neutrino beams at IHEP
Years

Protonbeam

Neutrino
beams

Detector(s)Results

1974
1982

Up to2x1012,
30
bunches,5µs spill
durationνµ , anti-νµfocusedbeam;
beam-dump

ITEP Spark
Neutrino
Detector

1. µ-pairs in ν-interactions;
2. search for short-lived particles
using nuclear emulsion;
3. σtot(νN), quasi-elastic scattering,
including limits on νµ-oscillation
parameters, νµe-scattering, etc.
4. prompt neutrinos (charm production
in pFe-interactions)

1985
2003

Up to
1.4x1013(booster),
29
bunches,
5µs spill
durationνµ , anti-νµfocusedbeam;
beam-dump;
short decaypath

1. ν (anti-ν)-inclusive scattering,
SKAT
Bubblestructure functions, νe-νµChamber
universality, exclusive channels(up to 1990); 2. prompt neutrinos

4th workshop on NBI, 7-11 November 2003

JINR-IHEP
Neutrino
Calorimeter

3. νe-oscillations with Neutrino
CalorimeterValeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino)2

Construction
Mechanical construction of chamber (type A)
Vbias
abdc

115156mm

22120mm

Y profile

1Beam

1516163 mm

Vbias

Vbias

116X profile

4th workshop on NBI, 7-11 November 2003

116 wires

116 wires

element a and delement b

Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino)3

Construction - 2
Main parameters of chamber A and B
Chamber A

Chamber B

Construction

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

16 strips, 140mm
working area

Material

beryllium-bronze alloy

aluminumSizewire of ∅ 200

40 x 8mm

Distance
between 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

Signalelectrode

4th workshop on NBI, 7-11 November 2003

Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino)

4Electronics
Schematicdrawing

chamber

20m
ADC+memory

Timing diagram

digitalization
beamτ ≥ 100µs

SignalTime5µs

5-10µs

4th workshop on NBI, 7-11 November 2003

5µs

Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino)

5Measurements (vacuum)
Originally the chambers were used inside of beam pipe under a pressure of ~10-2 torr

Beam profiles
Chamber A

Chamber B

Channelnumber

16 mm

Channelnumber

140 mmBeam profile for focused (chamber A) and wide beam (chamber B)

Number of δ-electrons
Number 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)

6

Measurements (vacuum) - 2
Linearity
spill duration varied from 20 ns to 5schamber signal is a sum of 14 central wires signals
intensity measured by BCT
Vbias= 0
Chamber signal,
relative units

Chamber A

1.0•1013

Beam intensity,
protons/cm2

the same dependency was observed for chamber B too
4th workshop on NBI, 7-11 November 2003

Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino)

7

Measurements (vacuum) - 3
Dependence of signal on pressure and bias voltagechamber signal is a sum of all wires signals
Chamber signal,
relative units

P ~ 1 Torr
P ~ 2x10-1 Torr
P ~ 5x10-2 Torr
P ~ 5x10-3 Torr

Bias voltage, Vfor 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)

8

The chambers in air
Focused neutrino beam
beam-pipetargetchamber1985 - 1994
beam
~5m~5-7m

Short decay path beam
beam-pipechamber target

absorber~ 1996beam~10m

4th workshop on NBI, 7-11 November 2003

Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino)

9

Measurements (air)Linearity
Chamber signal,relative units

Proton intensity in 1012 protons per spill (5s)Chamber signal,
relative units

Proton intensity in 1012 protons per spill (5s)
4th workshop on NBI, 7-11 November 2003

Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino)

10

Summary

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

4th workshop on NBI, 7-11 November 2003

Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino)11