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<p>simple calculate:</p>
<p>1.1^8.1=2.16, Gain at 1100V should be 3.1*2.16=6.7>6.5(chendi
list)(3.1is the gain at 1000V)<br>
</p>
<p>1500V : 1.5^8.1=26.7, =>G=3.1*26.7=82.7<102(chendi's)</p>
<p>So the relation not normally as G=a*V^b.</p>
<p><br>
</p>
<br>
<div class="moz-cite-prefix">On 2017/9/8 11:23, Xiaochao Zheng
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:1272309214.6891221.1504841035204.JavaMail.zimbra@jlab.org">
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12pt; color: #000000">
<div>Hi Cunfeng:<br>
</div>
<div><br data-mce-bogus="1">
</div>
<div>There is a slight difference here: When the curve is
linear on the double-log scale, one could have: <br
data-mce-bogus="1">
</div>
<div> gain = a * (HV)^b, where a and b are constants. Looking
at Chendi's data (see the spreadsheet file on the minutes),
the value of b seems to be about 8.1, which is likely to be
the number of stages for this PMT. In this case, the increase
in the gain per dynode is linear with HV, and the total gain
is HV raised to the power of number of stages, and thus
Chendi's results are reasonable and is consistent with what we
expect. <br data-mce-bogus="1">
</div>
<div><br data-mce-bogus="1">
</div>
<div>At the meeting JP said what CHendi showed agrees with JP's
experience. He said for the Hall A HRS detectors, when the HV
is increased by fixed amount (such as 100V each time), the
gain increase by a fixed scaling factor (for example, doubles
every 100V). THis can be either explained using the single
log scale function, or a power function as above.<br
data-mce-bogus="1">
</div>
<div><br data-mce-bogus="1">
</div>
<div>So I think the problem may be elsewhere:<br
data-mce-bogus="1">
</div>
<div>1) Can the PMT anode current saturate? <br
data-mce-bogus="1">
</div>
<div>2) Can the attenuator that Chendi used behave non-linearly?<br
data-mce-bogus="1">
</div>
<div>3) If we do a HV scan for the SDU3 module, is it possible
to show the same (weird) behavior? Can the SDU group do such
a scan to prove the method to be valid? (That we should get a
fixed Npe for different HV values)?<br data-mce-bogus="1">
</div>
<div><br data-mce-bogus="1">
</div>
<div>Thanks,<br data-mce-bogus="1">
</div>
<div><br data-mce-bogus="1">
</div>
<div>Xiaochao<br data-mce-bogus="1">
</div>
<div><br>
</div>
<div><br>
</div>
<hr id="zwchr" data-marker="__DIVIDER__">
<div data-marker="__HEADERS__">
<blockquote style="border-left:2px solid
#1010FF;margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;"><b>From:
</b>"cunfeng feng" <a class="moz-txt-link-rfc2396E" href="mailto:cunfeng.feng@cern.ch"><cunfeng.feng@cern.ch></a><br>
<b>To: </b>"申忱迪" <a class="moz-txt-link-rfc2396E" href="mailto:15600915869@163.com"><15600915869@163.com></a>, "Xiaochao
Zheng" <a class="moz-txt-link-rfc2396E" href="mailto:xiaochao@jlab.org"><xiaochao@jlab.org></a>, "solid ec"
<a class="moz-txt-link-rfc2396E" href="mailto:solid_ec@jlab.org"><solid_ec@jlab.org></a><br>
<b>Sent: </b>Thursday, September 7, 2017 10:56:18 PM<br>
<b>Subject: </b>Re: [Solid_ec] calculation<br>
</blockquote>
</div>
<div data-marker="__QUOTED_TEXT__">
<blockquote style="border-left:2px solid
#1010FF;margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;">
<p>Chendi,</p>
<p>I agree with Xiaochao that the Gain-V relation is
linearity under double-log axis as shown on the PMT
specification sheet, not single-log axis. You should
contact with the PMT company to explain why the Gain-V
results is not linearity under double-log axis.</p>
<p>Your PMT Gain raises much more, it should be the reason
the NPE decrease.<br>
</p>
<p>Cunfeng<br>
</p>
<br>
<div class="moz-cite-prefix">On 2017/9/7 22:26, 申忱迪 wrote:<br>
</div>
<blockquote
cite="mid:625d2aec.d5e2.15e5cbbcbc5.Coremail.15600915869@163.com">
<div
style="line-height:1.7;color:#000000;font-size:14px;font-family:Arial">
<div>hello</div>
<div><br>
</div>
<div>here is my calculation.</div>
<div><br>
</div>
<div>best regards<br>
</div>
<br>
<br>
<br>
<br>
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<div style="font-family: 'lucida Grande', Verdana,
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22.1px; font-size: small;"><span
data-mce-style="line-height: 22.1px;
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font-family: 黑体;">申忱迪 </span><span
data-mce-style="line-height: 22.1px;
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style="line-height: 22.1px; font-family: Arial;
font-size: small;" size="2"><i>Department of
Engineering Physics, Tsinghua University</i></span></div>
<div style="font-family: 'lucida Grande', Verdana,
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23.8px;"><span data-mce-style="line-height: 22.1px;
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<div style="font-family: 'lucida Grande', Verdana,
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