Use of multi wires chambers in air for profile measurements of intensive beams at IHEP (Protvino) 4 th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino)
Neutrino beams at IHEP Years Proton Neutrino Detector(s) Results beam beams ν µ , anti- ν µ 1. µ -pairs in ν -interactions; 1974 Up to ITEP Spark - 2x10 12 , Neutrino focused 2. search for short-lived particles 1982 30 Detector beam; using nuclear emulsion; bunches, 3. σ tot ( ν N), quasi-elastic scattering, beam-dump 5 µ s spill including limits on ν µ -oscillation duration parameters, ν µ e-scattering, etc. 4. prompt neutrinos (charm production in pFe-interactions) ν µ , anti- ν µ 1. ν ( anti- ν )-inclusive scattering, 1985 Up to SKAT 1.4x10 13 structure functions, ν e - ν µ - Bubble focused 2003 (booster), Chamber beam; universality, exclusive channels 29 (up to 1990); beam-dump; 2. prompt neutrinos bunches, short decay 3. ν e -oscillations with Neutrino 5 µ s spill path JINR-IHEP Calorimeter duration Neutrino Calorimeter 4 th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino) 2
Construction Mechanical construction of cham ber ( type A) V bias V bias V bias a d b c 1 1 2 Y profile 2 Beam 120mm 156mm 15 15 16 16 116 wires 116 wires 3 mm 1 16 element b element a and d X profile 4 th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino) 3
Construction - 2 Main param eters of cham ber A and B Chamber A Chamber B Signal Construction 14 central + 2x12 wires 16 strips, 140mm electrode connected in parallel, working area 38mm working area Material beryllium-bronze alloy aluminum wire of ∅ 200 � 40 � x 8mm Size Distance 0.8mm 1mm between wires/strips Bias plane 116 wires, 1mm step, 116 wires, 1mm step, beryllium-bronze alloy beryllium-bronze alloy Distance between signal and bias plane 3mm 3mm 4 th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino) 4
Electronics Schem atic chamber 20m draw ing ADC + memory Tim ing diagram digitalization beam τ ≥ 100 µ s Signal Time 5 µ s 5-10 µ s 5 µ s 4 th workshop on NBI, 7-11 November 2003 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 Channel Channel number number 16 mm 140 mm Beam profile for focused (chamber A) and wide beam (chamber B) Num ber of δ -electrons Number of � -electrons per proton (measured with V bias = 0): chamber A – 0.03, chamber B – 0.01 4 th 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 � s chamber signal is a sum of 14 central wires signals intensity measured by BCT V bias = 0 Chamber signal, Chamber A relative units 1.0• 10 13 Beam intensity, protons/ cm 2 the same dependency was observed for chamber B too 4 th 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 voltage chamber signal is a sum of all wires signals Chamber signal, P ~ 1 Torr relative units P ~ 2x10 -1 Torr P ~ 5x10 -2 Torr P ~ 5x10 -3 Torr Bias voltage, V for V bias = 0 the signal is equal for all pressures after first 1-2 years of use all chambers were operated with V bias = 0 4 th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino) 8
The chambers in air Focused neutrino beam beam-pipe chamber target 1985 - 1994 beam ~ 5m ~ 5-7m Short decay path beam beam-pipe chamber target absorber ~ 1996 beam ~ 10m 4 th 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 10 12 protons per spill (5 � s) Chamber signal, relative units Proton intensity in 10 12 protons per spill (5 � s) 4 th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino) 10
Summary The m ulti w ires cham bers w ere usefully used during m any years in vacuum and air for profile m easurem ents of intensive proton beam s. 4 th workshop on NBI, 7-11 November 2003 Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino) 11
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