Rainer Schicker, Univ. Heidelberg Cheile Gradistei, sept 26, 2005

Status chamber testing/database

• Chamber testing procedures finalized may 13

– See manual Vers. 5 in forum.gsi.de/Alice/TRD chamber tests

• Use of 109Cd source in testing

• Database

Rainer Schicker, Univ. Heidelberg Cheile Gradistei, sept 26, 2005

55Fe source

• 55Fe EC to 55Mn, K = 5.9, 6.5 keV

T.Lehmann, 2003

Transmission radiator at 5.9 keV is about 1%

Rainer Schicker, Univ. Heidelberg Cheile Gradistei, sept 26, 2005

55Fe source for gain uniformity

• N0 = photon flux from the source • A = absorption in radiator

• A = variation in absorption (radiator thickness,glue,..)

• Ns = number of photons into gas volume

Ns = N0 x (1-A)

Ns) = dNsdN0

.(N0) + dNsdA

. (A)

(Ns) Ns

N0~Ns

.(A)

(Ns)Ns

~ (A/1-A)(A)

A

for A ~ 0.99: (A/1-A) ~ 100

for A ~ 0.5: (A/1-A) ~ 1

Rainer Schicker, Univ. Heidelberg Cheile Gradistei, sept 26, 2005

absorption radiator

• Absorption measured as function of energy

T. Lehmann, 2003

transmission > 50 %:-> E(photon) > 10 keV

Source parameters:1) photon energy2) life time 3) no neutrons

-> 109Cd

Rainer Schicker, Univ. Heidelberg Cheile Gradistei, sept 26, 2005

109Cd source (453 d)

• 109Cd EC to 109Ag, K = 22.9, 26.0 keV

K

K

Ag*(7/2 +),E=88 keV

Collimator:Absorption (1mm Pb)at 88 keV ~ 90 %

Rainer Schicker, Univ. Heidelberg Cheile Gradistei, sept 26, 2005

109Cd spectrum

• 109Cd spectrum measured with TRD chamber

2nd peak at approx. 8 keV-> compatible with E(K of Z~29 (copper)

Confirmation by AEA: Casing material monel( 1/3 copper, 2/3 nickel)

Information by AEA: Casing material could be Titanium, (Z=22),E(K ~ 4.5 keV),Cd contains Silikat (Na-Al)

Rainer Schicker, Univ. Heidelberg Cheile Gradistei, sept 26, 2005

1d scan X-ray vs 109Cd source

• L1C1#020 measured with X-ray tube, Cd source

X-ray scan

Cd scan

Rainer Schicker, Univ. Heidelberg Cheile Gradistei, sept 26, 2005

2d scan X-ray vs 109Cd source

• L1C1#020 measured with X-ray tube, Cd source

X-ray scan

Cd scan

Rainer Schicker, Univ. Heidelberg Cheile Gradistei, sept 26, 2005

Conclusions

• 109Cd source can be used for measuring– Gain uniformity– Absolute Gain– Gain stability

• Absolute gain measurement has to be done with care with present Cd source (intensity 2nd peak might be collimation dependent)

-> Cd source with Titanium casing

Rainer Schicker, Univ. Heidelberg Cheile Gradistei, sept 26, 2005

Status database

• Sascha Freuen has graduated and left sep 15• Stefan Zimmer has started as HiWi and taken

over the database, no other involvement in TRD activities

• As of sep 22, writing of some leak rate parameters to database successful