Mu 2 e wire position scanner using Xray

Mu 2 e wire position scanner using X-ray Chiho Wang, Seog Oh Duke University

Wire position scanning • Goal: § Measure wire positions relative to optical survey points on the panel. § Measurement precisions: 25 μm in the direction perpendicular to the wire, 50 μm along the magnetic field axis. • Technique: § Using X-ray attenuation due to wire shadowing, detect reduction of photon counting rate due to wire blocking. • Plan: § Measure wire positions in 3 locations along the wire. (Measuring straws positions are also possible) § Scan either a Panel or a Plane in horizontal position only. 11/07/13 Chiho Wang, Seog Oh 2

Mu 2 e Xray Scanner 5”x 5’ U channel Linear slide 85 cm travel X-ray tube Collimator + Slit Straws Panel frame 2” screw rod (x 2) Supporting foot (X 2) 11/07/13 Chiho Wang, Seog Oh X-ray detector (5 cm ID straw) 3

Rotate X-ray to scan in stereo angle Linear slide X-ray tube 7. 764” Collimator + Slit Straws 11/07/13 X-ray detector Chiho Wang, Seog Oh 15° x n 4

Rotate X-ray to scan in stereo angle § Similar to stereo tracking and the expected resolution ~50μm. 1. Scan normally: x z 2. Scan with (a) tilted angle(s): u z 3. Calculate z position from x & u 11/07/13 Chiho Wang, Seog Oh 5

X-ray Slit Align to the wire direction and x-ray source X-ray tube Collimator & Shield X-ray Slit Adjust Slit holder 11/07/13 Chiho Wang, Seog Oh Rotation Adjustment Translation Adjustment 6

Mu 2 e Xray Scanner U channel Linear slides X-ray tube 2” screw rod (x 2) Collimator & Slit Supporting Foot (x 2) 11/07/13 X-ray detector Chiho Wang, Seog Oh Panel frame 7

X/Y Linear Slides • Orientalmotor EZS 6 E 085 -A + SCX 11 § § § 11/07/13 Ball screw system. Max. transportable mass: 60 kg (Hor. ), 7. 5 kg (Ver. ) Max. speed: 180 mm/s Resolution: 10 μm Stroke length: 85 cm USB interface Chiho Wang, Seog Oh 8

X-ray source • Oxford Instrument SN 94975 § § § Target: W Window: 0. 005” Be Anode V: 10 -50 KV Anode I: Max = 1. 0 m. A Power: Max = 50 W • Operating point: § Anode V=10 -20 KV § Anode I = 0. 01 -0. 02 m. A § Produce nominal count of 30 -200 KHz 11/07/13 Chiho Wang, Seog Oh 9

X-ray detector • Straw tube chamber § 5 cm ID, 170 μm wall made of Mylar backed Aluminized paper. § 100 μm Cu-Be sense wire. § Ar(80%)/CO 2(20%) , HV = 3. 5 KV • USB DAQ (Measurement Computing USB-1208 FS) § 1 MHz counter HV Amp 11/07/13 Chiho Wang, Seog Oh Dis. ECL TTL 10

Labview control • • Control stepping motor Read out X-ray detector Simple scanning function Control X-ray (manual for now) 11/07/13 Chiho Wang, Seog Oh 11

Scanning 25 μm wires + straw X-ray Slit Scan 25 μm wires + straw HV X-ray detector 11/07/13 Chiho Wang, Seog Oh 12

Misaligned X-ray slit w. r. t. wire 20 μm step, 50 μm slit, 10 KV, 0. 01 m. A wire Straw edge Slit misaligned ~ 1° 11/07/13 Chiho Wang, Seog Oh 13

X-ray slit aligned 20 μm step, 50 μm slit, 10 KV, 0. 01 m. A Wire (25 μm) wire Straw edge 11/07/13 Chiho Wang, Seog Oh 14

Repeatability Position (mm) • Repeated scanning of the same setup - testing stability of stepping motor and peak finding method. 11/07/13 Chiho Wang, Seog Oh 15

X-ray attenuation by straws Slit Stack of 5 Straws attached to the slit 25 μm wires + straw HV X-ray detector 11/07/13 Chiho Wang, Seog Oh 16

X-ray attenuation by straws 20 μm step, 50 μm slit, 10 KV, 0. 01 m. A Counting rate reduced: 30 KHz 20 KHz 11/07/13 Chiho Wang, Seog Oh 17

Longitudinal positioning Scanning 3 transverse slots 11/07/13 Chiho Wang, Seog Oh 18

• Using intercepts between rising/falling edges and background to determine slot longitudinal position • The uneven top is mainly due to uneven X-ray slit surface, and lesser due to X-ray going through different parts of X-ray counter. (The slit will be re-machined. ) 11/07/13 Chiho Wang, Seog Oh 19

Longitudinal positioning Distance between slots • 4 scans are done in various conditions: § 2 nd scan has the X-ray slit partially blocked (shortened). § 3 rd scan shifted X-ray counter ~6 cm § 4 th scan shifted X-ray counter again and scanned with finer steps and longer counter gate 2 nd scan 11/07/13 3 rd scan Chiho Wang, Seog Oh 4 th scan 20

Measure X&Y of the survey points (conceptual) Y X Wire and slot fixtures referenced to optical survey points on panel frame 11/07/13 Chiho Wang, Seog Oh 21

Measure the end survey point (conceptual) Optical survey reference Reference wire Tensioning mechanism Fixture fixation mechanism Reference wire Fixation mechanism Y Reference wire collimator X Slot for reference wire 11/07/13 Wire for Y position measurement Slot for X position measurement Chiho Wang, Seog Oh 22

Measure the middle survey point (conceptual) Fixture fixation mechanism Optical survey reference Slot for X position measurement 11/07/13 Reference wire Fixation & collimator Wire for Y position measurement Chiho Wang, Seog Oh Y X 23

Software • Create a data base for the wire position which can be read in by the reconstruction program. • Work in progress. • Once data base can be read in, will study the effect of wire misplacement on the physics. 11/07/13 Chiho Wang, Seog Oh 24

Summary • Critical components are in hand their functionalities are being tested: § § Stepping motor X-ray tube X-ray detector (5 cm ID straw tube) Labview DAQ/control • Study shows we can measure wire positions better than 25 um and straw positions about 50 um • Should be ready to scan the 1 st prototype panel. § Map wires with/without HV/pressure • Software development in progress 11/07/13 Chiho Wang, Seog Oh 25

Backup Slides

Setup for feasibility study X-ray source ~40 cm 75μm slit 4 cm long ¼” thick Wires to scan 3 cm Amp. /Disc. HV Straw chamber (5 cm ID ) 11/07/13 Chiho Wang, Seog Oh Amp Slide 27

X-ray counting rate vs slide position 1 mil step, 1 sec counter gate 25μm W const 1 -const 2*exp(-0. 5*((x-mean)/sigma)^2) 178μm W 25μm W 100μm Cu-Be 178μm W 11/07/13 100μm Cu-Be Chiho Wang, Seog Oh 28

Shadowing wires with a straw 11/07/13 Chiho Wang, Seog Oh 29

25μm wire shadowed by straw Peak amplitude shifted down, not reduced 25μm W 100μm Cu-Be 178μm W Straw edge 11/07/13 Chiho Wang, Seog Oh 30