4 th workshop on NBI, 7-11 November 2003Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino) Use of multi wires chambers in air for profile measurements of intensive beams at IHEP (Protvino)

4 th workshop on NBI, 7-11 November 2003Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino)2 YearsProton beam Neutrino beams Detector(s)Results Up to 2x10 12, 30 bunches, 5s 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) Up to 1.4x10 13 (booster), 29 bunches, 5s 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 channels 2. prompt neutrinos 3. e -oscillations with Neutrino Calorimeter Neutrino beams at IHEP

4 th workshop on NBI, 7-11 November 2003Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino)3 Construction 116 wires V bias 116 wires Y profile Beam 3 mm V bias a bc d 1 16 X profile 120mm 156mm element a and d element b Mechanical construction of chamber (type A)

4 th workshop on NBI, 7-11 November 2003Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino)4 Construction - 2 Chamber AChamber B Signal electrode Construction 14 central + 2x12 wires connected in parallel, 38mm working area 16 strips, 140mm working area Materialberyllium-bronze alloy aluminum Size wire of  200  40  x 8mm Distance between wires/strips 0.8mm1mm Bias plane 116 wires, 1mm step, beryllium-bronze alloy Distance between signal and bias plane3mm Main parameters of chamber A and B

4 th workshop on NBI, 7-11 November 2003Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino)5 Electronics ADC + memory chamber 20m Schematic drawing Timing diagram   100s beam digitalization 5s5s5-10s5s5s Time Signal

4 th workshop on NBI, 7-11 November 2003Valeri 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 profiles Chamber AChamber B Number of -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 2003Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino)7 Measurements (vacuum) - 2 Chamber signal, relative units Beam intensity, protons/cm 2 Chamber A 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 the same dependency was observed for chamber B too

4 th workshop on NBI, 7-11 November 2003Valeri 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 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 2003Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino)9 The chambers in air Focused neutrino beam target beam ~5m~5-7m chamber beam-pipe Short decay path beam targetabsorberchamberbeam-pipe ~10m ~ 1996 beam

4 th workshop on NBI, 7-11 November 2003Valeri Falaleev(CERN) & Yuri Sviridov (IHEP, Protvino)10 Measurements (air) Linearity Proton intensity in protons per spill (5  s) Chamber signal, relative units Chamber signal, relative units

4 th workshop on NBI, 7-11 November 2003Valeri 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.