Beam Loss Monitor Production. IHEP (Protvino) V. Grishin, A. Koshelev, A. Larionov, V. Seleznev, M. Sleptsov, A. Sytin At IHEP manufactured: Ionization chambers (IC) ~ 4300 pcs. (2006 ÷ 2007) Secondary emission chambers (SEM) ~350 pcs. (2007) Little ionization chambers (LIC) ~ 300 pcs. (2011)

There are some main procedures of production BLM: Cleaning of the chamber components Welding and assembling of the chambers Pumping, baking, leak testing and filling of the chambers Final assembling of the chambers with electric box and leak current test

Cleaning of the chamber components Immediately before beginning of the assembly Al and st.steel components passed next cleaning steps: Ultrasonic cleaning in an alkaline detergent solution (NGL SP ALU 20g/l) at 65°C, 30 minutes –st.steel, and 10g/l, 20 minutes for aluminium Rinsing at room temperature in distilled water Ultrasonic cleaning in a distilled water 5 minutes Drying in a hot air at 150°C The quality of the cleaning checked by (CERN) Technology Department with help X-ray photoelectron spectroscopy in regular intervals

TIG welding of the IC and SEM Tightness welded components checked with help He leak detector PhoenixL300 Leaks more than 1∙10E-10 l∙mbar/s are not allowed

Assembling of the ionization chambers

Scheme of vacuum stand for pumping, heating and filling of ionization chambers

Vacuum stand with the mounted monitors without and with heating containers

Vacuum stand with the mounted SEM before and after heating

Pinch-off the SEM after heating cycle

PC interface for the control heat treatment, pumping and filling of the chambers The temperature monitoring of all heating chambers The pressure monitoring in the stand during pumping The pressure monitoring of the filling gas N2 Calculation the needed N2 pressure for execute pinch-off The pinch-off pressure at real temperature must be correspond to 1100mbar at 20°C

Stand heat treatment cycle of the ionization chambers Time of leak detection and filling TimeTime Time of leak detection Temperature, C Time [hour]

q average ~ 2x10E-11[l mbar/s sm2]

q average ~ 5x10E-13[l mbar/s sm2]

Residual gas spectrum before N 2 filling of ionization chamber at room temperature

Certificate of N 2 gas quality “Linde Gas RUS Company” Name of components Percentage 1. Volume part of Nitrogen ≥ 99,999 % 2. Volume part of Oxygen ≤ 0,0005 % 3. Volume part of Hydrogen ≤ 0,0002 % 4. Volume part of organic in a count to methane ≤ 0,0001 % 5. Volume part of water vapour ≤ 0,0007 %

Leak detection Time pinch-off Leak detection mbar

Investigation of heater containers possibility for heat treatment SEM

T=300°C Time pinch-off T=200°C Time after switch on analyzer Residual gas spectrum versus time for SEM after finishing of getter activation

Residual gas spectrum versus time for LIC at room temperature after heating and before filling. Leak detection

Choice of LIC working pressure with two and one shieldings Pressure N 2, [ mbar] U, [kV] Current, [pA] 100 1,5 < ,0 2,3spark 200 2,0 3,0 < ,5spark 300 2,5 3,0 < ,0spark 400 3,0 < ,0 < 1

Final assembly of the chambers with electric box and leak current test IC and SEM are passed leak current test 3 times during cycle production: After full assembling on air After filling of gas working After assembling chambers with electric box In all cases the current must be less 1 pA

GRATEFULNEES IHEP production team thanks: B. Dehning E.B. Holzer, P. Chiggiato, G. Ferioli, J.M. Jemenez, D. Kramer, M. Taborelli, I. Wevers and all BLM team