Subject: Oil and PVC quantities in MACRO (scint system)
From: Erik Katsavounidis (Erik.Katsavounidis@lngs.infn.it)
Date: Wed Nov 17 1999 - 05:28:52 EST
Hi all--
This is an accounting of oil and PVC quantities in MACRO that could
be of interest in preparing for and decommissioning the MACRO detector.
It was prepared in April 1999 upon Raffaele's request. There is a minor
addition lately that includes more precise dimensions of the counters
that is described in section 4. I didn't recalculate oil and PVC based
on the most recent numbers- it is less than 5% change.
This note resides as html document at
http://wsgs02.lngs.infn.it:8000/macro/oil_pvc_sum.html
but I'm forwarding also to the interested parties, including the archiving
in our mail lists.
--Erik
PS: The text dump of the page follows.
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Report is also available in postscript and tex here:
* Click to download source tex file: OIL_PVC_SUM.TEX
* Click to download postscript: OIL_PVC_SUM.PS
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The MACRO Scintillator System
E. Katsavounidis
Caltech
29 April 1999
1. Overview
All MACRO scintillator counters are parallelopided-shaped with an
approximate nominal length of 12m and rectangular cross-section of 75cm X
25cm. The active, highly transparent, mineral-oil based scintillator fills
about 11m of the counter's length and it reaches a nominal height of 19cm
and 46cm for the horizontal and vertical counters respectively. This varies
by a few millimeters from tank to tank and also from end to end within the
same tank. The end to end variations are the result of the fact that
counters are not perfectly level. The two ends of each counter house the
reflectors and the photomultipliers (PMTs) that collect the scintillation
light. Horizontal counters are instrumented with two PMTs in each end while
vertical counters with just one PMT in each end.
In the total of 476 counters that make up the scintillator system in MACRO,
there are approximately 670m^3 of mineral-oil based scintillator mix and
65m^3 of PVC-made counters.
In addition to these amounts, there exist in Hall B (within MACRO's attico
and the mezzanine) approximately 10 counters that are empty. Moreover, in
the external lab facilities an approximate amount of 6000 lt of scintillator
mix and mineral oil is kept in 200lt drums.
2. The scintillator tank construction and filling
All scintillator counters are made of 0.63cm thick PVC sheets. They are
divided into three chambers which are separated by highly transparent
windows made of 0.32cm clear PVC. The inside walls of the counters are lined
with a commercial white vinyl-FEP material. The indices of refraction for
the FEP-liner is n_liner=1.33 and of the scintillator mix
n_scint=1.4750+-0.0005. The main central chamber (~11m long) of each
scintillator counter is filled with mineral oil-based scintillator mix. A
high purity mineral oil is used as a solute; its attenuation length was
measured by LED (light emitting diodes) and LASER spectrophotometer to be
greater than 20m at the wavelength of 425nm\nolinebreak The scintillant is a
mixture of pseudocumene (1,2,4-trimethylbenzene), PPO (2,5-diphenyl-oxazole)
and bis-MSB (p-bis[o-methylstyryl]benzene). Pseudocumene (C_9H_12) is the
primary fluor, emitting light at a wavelength of ~290nm. PPO (C_15H_11NO)
works as the first stage wavelength shifter to ~360nm and finally the
bis-MSB (C_24H_22) shifts the wavelength to ~420nm, which is the sensitive
wavelength region of the PMT. The final MACRO scintillator mix is made of
96.4% mineral oil, 3.6% pseudocumene, 1.44g/l of PPO and 1.44mg/l of
bis-MSB. Both horizontal and vertical counters have their end chambers
filled with mineral oil, the same oil used in the scintillator mix. Figures
1.a and 1.b show the detailed geometry of each type of counters.
3. Drawings of end-counter geometry
[Image] (a)
[Image] (b)
Figure 1. Details of scintillator counter end--chambers (a) horizontal (b)
vertical
4. Top view of horizontal and vertical counters
Horizontal counter, top view. Distances are as follows:
AB=EF=20cm
BC=DE=33cm
CD=1118cm
Total length AF=1224cm
A B C D E F
---------------- ......... ----------------
| | | |
----- | | -----
| |<-- clear PVC divider -->| |
----- | | -----
| | | |
----- | | -----
| | | |
----- | | -----
| | | |
---------------- ......... ----------------
Vertical counter, top view. Distances are as follows:
AB=EF=28cm
BC=DE=20cm
CD=1120cm
Total length AF=1216cm
A B C D E F
---------------- ......... ----------------
----- | | -----
| |<-- clear PVC divider -->| |
----- | | -----
---------------- ......... ----------------
5. Summary numbers on oil and PVC quantities
Summary of scintillator counters in MACRO
1) HORIZONTAL counters: total of 294 with overall dimensions (approximate)
11.8m x 0.75m x 0.25m
These counters are employed on the "BOTTOM","CENTER" and "TOP"
faces of the detector
2) VERTICAL counters (standard): total of 170 with overall dimensions
(approximate) 11.8m x 0.60m x 0.25m
These counters are employed on the "EAST","WEST","NORTH" and "SOUTH"
faces of the detector
There exists a variant of the above "VERTICAL counter" that is ~30cm
sorter. We will refer to this as "TYPE8". There are 12 such counters
with overall dimensions (approximate) 11.5m x 0.60m x 0.25m
These counters are employed on the 8th layer of the "EAST" and "WEST"
faces of the detector
Summary of scintillator oil and PVC amounts in MACRO
(We have assumed density for oil: 0.86 gr/cm^3
and for PVC: 1.40 gr/cm^3)
PVC is 0.63cm thick. Clear PVC (separating main chamber) is 0.32cm thick
Per Horizontal counter SCINTILLATOR MIX (m^3): 1.54 (kgr): 1325
Per Horizontal counter TANK END MINERAL OIL (m^3): 0.07 (kgr): 59
Per Horizontal counter PVC (m^3): 0.15 (kgr): 204
Per Horizontal counter CLEAR PVC (m^3): 0.00 (kgr): 1
Per Vertical counter SCINTILLATOR MIX (m^3): 1.01 (kgr): 873
Per Vertical counter TANK END MINERAL OIL (m^3): 0.04 (kgr): 39
Per Vertical counter PVC (m^3): 0.12 (kgr): 169
Per Vertical counter CLEAR PVC (m^3): 0.00 (kgr): 1
Per TYPE8 Vertical counter SCINTILLATOR MIX (m^3): 1.00 (kgr): 857
Per TYPE8 Vertical counter TANK END MINERAL OIL (m^3): 0.04 (kgr): 39
Per TYPE8 Vertical counter PVC (m^3): 0.12 (kgr): 166
Per TYPE8 Vertical counter CLEAR PVC (m^3): 0.00 (kgr): 1
Total SCINTILLATOR MIX (m^3): 637.52 (Kgr): 548266
Total TANK END MINERAL OIL (m^3): 28.48 (Kgr): 24491
Total PVC (m^3): 64.92 (Kgr): 90889
Total CLEAR PVC (m^3): 0.49 (Kgr): 683
6. References
For further details the reader is referred to MACRO's first technical paper
already published:
The MACRO Collaboration,
First Supermodule of the MACRO detector at Gran Sasso,
Nucl. Instr. Meth. Phys., A324 (1993) 337-362.
Further details on MACRO's hardware, electronics and performance can be
found in the technical paper describing the detector's final configuration;
this is in preparation (please e-mail me if you need more info)
kats@hep.caltech.edu
http://wsgs02.lngs.infn.it:8000/macro/
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E. Katsavounidis Apr 29, 1999
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